Craig R. Sweet, M.D.
Reproductive Endocrinologist

Corey Burke, B.S., C.L.S.
Laboratory Supervisor

Introduction

Asking what determines the success rates in embryo donation is an excellent question. The answer, as one might expect, is neither simple nor completely understood.

Embryologists and physicians try to choose the fewest number of healthy embryos for fresh transfers to increase success rates while minimizing multiple pregnancy rates. It is indeed a delicate balance. For example, it is well understood that in Europe, physicians transfer fewer embryos but patients also suffer significantly lower success rates than in North America. (Boostanfar R, et al. Fertil Steril 2012)

What variables do we examine to estimate probable success?

Since donated embryos are cryopreserved, the variables become even more complex compared to fresh embryos. In combining a great deal of published data and over 20 years of IVF and embryo transfer experience, we came up with what we feel are the variables which seem to influence success rates:

The above variables influence EDI’s decision to both accept embryos from other facilities as well as determine how many donated embryos should be thawed/warmed to achieve a successful delivery.

The importance of the embryo recipient’s health should not be underestimated

In a previous blog, we described how important it was for our embryo recipients to be healthy. (link) Inadequately treated health problems, harmful medications, recreational drug use as well as smoking and weight concerns all play a potential role affecting success rates. It is clear that success depends on both the quality of the donated embryos and the overall health of the recipient.

Are all donating IVF facilities the same?

We understand that not all IVF facilities have the same success rates. Some facilities will have provided EDI donated embryos with consistently high implantation rates while others may provide embryos of consistently lessor quality. EDI examines a facility’s past fresh and frozen embryo transfer pregnancy rates as well as its past history of providing EDI with donated embryos. It does, however, take a fair amount of time to seemingly identify a trend but we endeavor to examine all the variables we can. Our contact management database system was recently upgraded to track these variables more consistently.

Do your embryos make the grade?

Understanding that all of the above variables are quite complex, we endeavored to find a simple way to convert the data into something patients could more easily understand. Since nearly all patients understand the basic A, B & C grades we used to receive in school, we modeled our grading of the embryos around these letter grades.

We created a mathematical model to assess a number of the above variables, converting the final analysis to A+, A, A-, B+, B and B- letter grades. Interestingly, we found the model really did help to predict delivery rates and continue to use it to this day to grade individual embryos as well as entire sets of donated embryos.

What information do we gain on the day of thaw and embryo transfer?

Most frequently, the embryos are thawed just hours before transfer. At times, we may thaw them days prior if, for example, they were frozen early in their development and we want to grow them further before deciding how many to transfer. Therefore, the following last set of variables will also influence success rates:

If 100% of the embryos, perhaps three out of three, survive the thaw and look healthy, we feel this is a good sign. If only 50% survive, for example perhaps only two of four, then we are concerned that the overall implantation rates will be reduced and that we might need to find more embryos to transfer just to get to the “finish line” of pregnancy and delivery. Ultimately, we want at least two high-quality embryos or up to four less certain quality embryos placed on the day of transfer.

 What are the national success frozen embryo transfer delivery rates?

In 2009, the CDC reported that there were 26,069 frozen embryo transfers performed in the U.S. with an average delivery rate of 31% per embryo transfer procedure. In addition, there were 6,074 frozen embryo transfers using embryos created from donated eggs (i.e., younger women) with slightly higher delivery rates of 34%. Please recall that donated embryos generally come from the very same types of patients listed in these success rates.

What are EDI’s success rates?

We do our best to screen the embryos, carefully trying to choose the embryos most likely to implant. We estimate delivery rates with donated embryos to range from 27 – 42%, depending on the many variables listed in this blog, with a multiple pregnancy rates of 20-25%. We wish the success rates were higher, but please understand that frozen/thawed embryos implant and grow less frequently than fresh embryos and these percentages are entirely consistent with the frozen embryo transfer success rates described in 2009, which ranged from 31-34%.

Even with the slightly lower delivery rates compared to fresh embryo transfers, embryo donation remains one of the best and most cost-effective options for patients who cannot otherwise afford egg donation or qualify for adoption. Embryo donation still allows a woman to experience pregnancy and delivery while bonding, nurturing and protecting the ongoing gestation.

Summary

There are many variables that go into determining the potential success rates for a given set of donated embryos. First, we attempt to examine these variables carefully in deciding if EDI will accept the donated embryos. Second, we use this same information to determine how many embryos we should thaw/warm and eventually transfer. The process remains a bit of an ART (pun intended) since the complete understanding of how all of these variables influence each other and the ultimate success rates are yet to be fully known.

References

“Annual ART Success Rates.” Centers for Disease Control and Prevention. Division of Reproductive Health, 19 Apr. 2012. Web. 24 Apr. 2012. <http://www.cdc.gov/art/ARTReports.htm>.

Boostanfar R, Mannaerts B, Pang S, Fernandez-Sanchez M, Witjes H, Devroey P; Engage Investigators. A comparison of live birth rates and cumulative ongoing pregnancy rates between Europe and North America after ovarian stimulation with corifollitropin alfa or recombinant follicle-stimulating hormone. Fertil Steril.  2012 Mar 27.

By: Vicki D., an embryo donor

“In the order of nature we cannot render benefits to those from whom we receive them, or only seldom. But the benefit we receive must be rendered again, line for line, deed for deed, cent for cent, to somebody.’ – Ralph Waldo Emerson, Compensation

On May 13, 2010, I made a decision. It wasn’t your normal everyday decision on things like what shoes to wear, where to have lunch, or which shade of lipstick to buy. It even surpassed those important decisions we encounter in life such as what house to buy, the most lucrative financial investments and selecting the best care for elderly parents. It was a decision much more substantial, incredibly emotional and most importantly, everlasting. It was regarding the fate of our embryos. Yes; five embryos, frozen, suspended in time – a significant and extraordinary reminder of a successful IVF cycle producing twin girls just two years prior. Considering that my family was now complete, the desire to have more children had abated. But the process was far from over and I knew this going in. There are five potential lives to consider currently residing in a sub-zero environment. So the question remained… what did one do with extra embryos when one’s need or desire to expand your family has subsided?

In my quest to determine the future of my five frozen embryos, I discovered several options to choose from. These ranged from permanent storage – or in some cases “abandonment,” destruction, donation to stem-cell research, donation to the IVF clinic lab, or donation to an infertile couple or person in need. Continued voluntary storage brought unnecessary substantial fees, not to mention the inevitable procrastination of decision making. Abandonment wasn’t an option for obvious reasons as I felt a responsibility towards these embryos. The only things I have ever abandoned in my life were the occasional art project or my first premature marriage in my early twenties. The concept of destruction simply didn’t make logical sense. Why go through all the expense and trouble of creating embryos that one day would be destroyed because there was no better option considered? Stem-cell research or IVF clinic donation seemed like fair choices since I wouldn’t have my twins without past research in IVF. Even so, there had to be a better option available that would help promote the preservation of life and help out infertile couples desperately wanting a baby.

I remember the years of anguish I experienced being infertile. Everywhere I went I saw pregnant women or newborn babies. It became an obsession, perceived as something so intangible for me yet came so easily for others. There would be no remedy but a child. Why not help another couple expand their family? Why not help end the anguish? Why not “Pay it Forward” to the infertile community in such desperate need? The simplest answers to these questions became the best option.

So the decision came with three stages. Firstly, there was the genetic hurdle to consider. There is something about setting your genetic code, or more specifically, your potential genetic offspring, free into the world that can be somewhat unsettling. Where will these embryos end up, will they survive and what kind of life will they have? Will they know their history? Will they have questions? Will they look like me? But in the greater scheme of things, do these questions really matter?

The value and definition of family transcends any DNA makeup.

In the pursuit of the family unit, we tend to look beyond the genetic code and focus on the family element. The concept of having a family does not automatically equate to comparable genetic material as can be seen with any family with an adopted child. It’s about being part of a team, functioning as a whole and sharing your love and commitment to live and experience life together.

Secondly, there is an element of giving back; Paying it Forward to the infertile world. Donating the embryos was my way of paying back what I was so very fortunate to finally have – a family. Prominent memories of being unfulfilled without children are still fresh in my mind. I honestly believe that donating my idle embryos to someone in need helps to promote the probability of life.

And finally, chance. The chance to help someone build a family, the chance of potential life for the embryo, the chance for you to give the greatest gift in life, the chance to take a chance! So for any of you out there who find yourselves with important decisions to make about your embryos in storage, think back a bit to your own infertile days. That memory will help guide you to do the right thing for someone with the same needs and desires as you have. Take a chance and do something good for humanity.

Donating the embryos was my way of paying back what I was so very fortunate to finally have – a family.

In the end I trusted Embryo Donation International (EDI) and Dr. Sweet with my precious embryos. I knew that with their high ethical standards and sheer devotion to the embryo they would give my embryos a chance at life, and hopefully help to build another family, just like they helped to build mine. And on every Mother’s Day ever since the donation I hope and wonder that by liberating my embryos they were able to help create another family somewhere out there and that they are as happy as I am.

Vicki D.
Mom, a Loving Wife and now, an Embryo Donor
torig71@gmail.com

By: Craig R. Sweet, M.D.
Reproductive Endocrinologist
Info@EmbryoDonation.com

The “Defunding” of a Government-Supported Program

On March 2, 2012, it was reported that the Obama Administration wanted to defund the embryo donation/adoption awareness federal program that has been run by the Office of Population Affairs, part of the U.S. Department of Health and Human Services. Spokespeople from Nightlight Christian Adoptions, the National Embryo Donation Center and Snowflakes Embryo Adoption programs were quoted as opposing the defunding decision. It should be noted they all had received or were receiving funding from the federal program, so their reactions were not unexpected.

Initially, the federal program was created in response to President Bush’s push to use cryopreserved embryos to create families and steer away donations from human embryonic stem cell research. Since 2002, over 22 million dollars has been spent by the federal government on the awareness programs.

The Predictable Response

Certainly during an election year, the firestorm that followed was probably predictable.

There were calls stating that the Obama Administration was “pro-abortion,”

I’ve never met such a person in my entire life, although many have been “pro-choice.”

Congressman Chris Smith, a New Jersey Republican, was quoted a saying, “Assertions that leftover embryos are better off dead so that their stem cells can be derived is dehumanizing and cheapens human life.”

Come on now… this decision does not mean that all cryopreserved will be destroyed. It simply means that all of us who are dedicated to the concept of embryo donation need to work harder and smarter with non-federal funds to make certain patients are aware of the embryo donation option.

Mailee Smith, staff counsel at the “pro-life” Americans United for Life, was quoted, “What we’re seeing is the elimination of the moral solution.”

Nothing could be further from the truth. Many programs throughout the country offer embryo donation and will continue to do so long after federal funding disappears.

Could we all just trim the hyperbole a bit?

Is it a Coincidence that the Phrase “Embryo Adoption” Predated the Personhood Amendments?

I suggest paying less attention to the hype and instead examine the realities of the ways that federal funding can influence the competitive free market with unintended consequences. The propagation of the term “embryo adoption” sprouted the appearance of the personhood amendments and legislation, which are focused on declaring that eight-cell early embryos are people. The consequences of these enactments are far reaching, including monumental legislative changes, restrictions on the care of women, and severe restrictions to the treatment of the infertile patient. (See my previous blog on the Mississippi Amendment here.)

Not Sour Grapes but Concerns Regarding Discrimination

Let it be understood that Embryo Donation International (EDI) applied last year for the federal funding in question, but we were not awarded a grant. In partnership with professors at Florida Gulf Coast University, we proposed thirteen different fresh and innovative projects to increase awareness, as well as provide embryo donation services. While we were disappointed, we were not surprised that the organizations, for the most part, receiving funding had been granted it before and this was our first submission. EDI was not previously dependent on the funding so there were no significant changes in our day-to-day operations. The projects are slowly being rolled out, funded instead by SRMS/EDI.

What bothered us was that over the years some of the organizations receiving the bulk of the funding were faith-based and discriminated against some patients. While the projects themselves were potentially more neutral, the organizations were not. Health and Human Services (HHS) apparently looked only at the proposals in determining the awards, making the awarding of grants potentially flawed.

The grant process essentially compartmentalized the proposals. If an organization provided certain services, which the federal government did not fund directly, but the organization was awarded a grant to provide other services, the government essentially compartmentalized the grant money separate from the procedures it didn’t directly support. I understand the concept but do not feel the grant committees should have made the decision based only on the grant proposals. They also needed to take into account the overall views and beliefs of the organization requesting funding. There needs to be times when the government must look at the trees and not just the leaves.

I believe there were instances where the funds should be withheld. The funded organizations should have provided a minimum standard of practice guidelines in line with the non-discrimination clauses outlined in the grants. Entities awarded the grants should not have discriminated with regards to race, religion, ancestry, gender, marital status or sexual preference.

Being a faith-based embryo donation/embryo adoption organization also directly or indirectly excludes some patients, making it uncertain if the federal government should directly support such facilities, especially taking into account the separation of church and state. I know that faith-based embryo donation/embryo adoption entities were strongly supported by past administrations but should a neutral organization that does not discriminate and makes all faiths feel totally welcome be placed at a higher priority now? Is this more ethical and fair? Is this a better use of the shrinking tax dollars? Is it time for the federal government to reconsider their goals?

If both discrimination and faith-based issues were actually taken into account, many of the organizations discussed here never would have received the original federal funds.

It is not that I want these organizations to go away. Quite the contrary, they often do a great job, provide excellent services and fill a much-needed niche. Their funding should, however, be through sources other than the federal government because of the bias inherent to their provision of services.

Can the Government Afford Providing the Grants?

Understanding that the U.S. is running a severe deficit, when are we ever going to be willing to make difficult decisions? How are we ever going to get control of the budget if we can’t trim existing programs that may serve an important few when the many need assistance? We all need to look at the big picture and understand that “business as usual” is not practical in the current economic climate. I may be falling on the sword a bit, but shouldn’t we all be willing to sacrifice? Hey, I’m all for creating little taxpayers to help pay off the deficit. I’m just not sure that we can afford to do so through a government in the red. To do so with organizations that discriminate makes absolutely no sense at all.

In Summary

If federal funding is to continue, it needs to be provided to organizations, and not necessarily my own, which do not discriminate and are not faith-based. In addition, giving “embryo adoption” programs federal funds so they can support personhood amendments should be reconsidered. Having the government eventually spend even more money and time contesting the amendments and statutes in court defies understanding. Perhaps the congressional appropriations committees, who will make the final decision regarding federal funding, will take the concepts of non-discrimination and non faith-based alternatives into account and fund the programs with new and fairer goals.

Rest assured, unlike the rhetoric would lead one to believe, embryo donation is here to stay, regardless of the decisions of Congress and the grant process. How do we know? We’ve been providing the service for 11 years and will continue to do so in the years ahead, without cessation, as long as there are cryopreserved embryos available to donate.

Craig R. Sweet, M.D.
Reproductive Endocrinologist
Embryo Donation International
www.EmbryoDonation.com

By: Craig R. Sweet, M.D.
Reproductive Endocrinologist
Info@EmbryoDonation.com

Introduction

There are times when we need to exclude patients when they contact Embryo Donation International (EDI) to become an embryo recipient. While not an easy decision or discussion, I thought it was time to explain our rationale when needing to, at least temporarily, exclude potential embryo recipients.

In a way, the blog we recently wrote on the ranking of potential embryo recipients dovetails into this discussion. In this blog, we described what we thought was an appropriate ranking system prioritizing those patients with the greatest need.

Our discussion here focuses on the patients who apply but who are never ranked because EDI feels they should be excluded because of any number of the reasons described below.

Excluding Potential Embryo Recipients Due to Maternal Risks

The decision to exclude a patient from embryo donation is really, in some ways, no different than the decision we have to make with other infertility patients.

Relative contraindications to pregnancy

There are occasions when certain conditions should probably be corrected before pregnancy takes place since pregnancy will often worsen or complicate the condition. Examples may include gallbladder disease and ovarian cysts or surface uterine fibroids that are five+ centimeters in average diameter. Treating these problems once pregnancy is established is very difficult, so it may be best to control the situation while we still can and correct the potential problem first before conception.

Strong contraindications to pregnancy

Patients who would be at significant risk of illness or even death should pregnancy occur include those suffering from cancer, poorly controlled systemic lupus, pulmonary hypertension or diabetes, to name a few important disease states.

Infrequently we have to be a bit paternalistic and say “no,” understanding that we may cause great harm to our ill patients by assisting them to become pregnant.

Excluding Potential Embryo Recipients Due to Risks to the Embryo/Fetus

The trickier decisions involve those patients where the potential for delivery of a live child is measurably reduced. Patients with decreased embryo implantation rates and those who are at an increased risk for spontaneous loss or at an increased risk for premature delivery/stillbirths fall into these categories.

Some of these examples are listed below:

* The effects of obesity or morbid obesity with regards to implantation rates and spontaneous loss rates are controversial.

The “Grey” Exclusion Zones

Out of the list above, one of the most difficult categories involves those patients who are obese or morbidly obese and their potential reduction in implantation rates and increased spontaneous loss rates. Some articles show a significant reduction in implantation rates and an increased risk of spontaneous loss while others show contradictory results. While a comprehensive review of this topic goes beyond the scope of this blog, I believe there are a few things we understand:

• Patients with glucose intolerance and insulin resistance, regardless of weight, are at a higher risk of developing gestational diabetes during pregnancy and the potential complications associated with this disease.
• Patients who are obese or morbidly obese are clearly at risk during pregnancy for a host of issues, including preeclampsia, hypertension, large for gestational age babies, prematurity, stillbirths, gestational diabetes, Cesarean section deliveries and the risks associated with these surgeries.

There is only one preliminary study specific to embryo donation that did not show a consistent decrease in pregnancy rates as weight increased (Body Mass Index: BMI) but the trends were present suggesting an average reduction in overall pregnancy rate of 33% for obese and morbidly obese patients with a BMI of 30 or more. (Finger R., et al. 2011) We await the detailed publication of this important study to better understand this issue.

Weight loss is terribly difficult for patients and takes a great deal of time. Sometimes surgery, such as a gastric band or intestinal bypass surgery, may be the best option. These issues are the thorniest to decide, with pressure applied by potential embryo recipients who do not fully understand how their weight may contribute to failed implantation or pregnancy loss, though it certainly places them and their unborn offspring at greater risks during the pregnancy.

Surrogacy as an Option When Material/Embryonic/Fetal Risks are Too High

Some of the issues discussed in this blog can be treated. Then the potential embryo recipient can be moved out of the exclusion zone. Some of these issues are not treatable, so options such as surrogacy and/or adoption may be better alternatives.

While some embryo donation programs refuse to allow surrogacy, EDI feels this is an excellent alternative. For example, is it ethical for EDI to ask that the patient with asymptomatic uterine fibroids, which may significantly reduce implantation or increase pregnancy loss rates, be surgically removed in a patient who fears surgery? Is gestational surrogacy a better alternative?

In Summary

We do not mean to be cruel or judgmental but are forced to make difficult decisions regarding the acceptance or exclusion of embryo recipients. We owe it to the potential embryo recipients to give them the best chance possible, understanding there are medical conditions that may severely impair their chances for success. We owe a debt of gratitude to the embryo donors and take seriously the responsibility of finding a healthy patient for their embryos  hoping to maximize the chances that the embryos will survive and thrive. Lastly, and certainly not least, we owe it to the embryos to make certain they have the best chance possible.

Unfortunately, we sometimes have to make the difficult decision to exclude a potential embryo recipient, at least temporarily, until the medial concerns are remedied or certainly improved.

References:

Finger R, et. al. Obesity and the ability to achieve pregnancy in embryo donation. Fertil Steril 2011;96(3)-S172.

Marna Gatlin of PVED

Exploring what we know – Marna Gatlin, Founder Parents via Egg Donation and guest blogger

I was asked recently what I thought about embryo donation vs. egg donation. Is a parent via egg donation the same as a parent via embryo donation?  What do they have in common?  Or are they very different?

My knee jerk reaction was “Well doh, of course they are the same.  They are both embarking upon a unique journey to become parents right?”

When I thought more about it, the word “versus” jumped out at me.  Did the individual asking the question really mean “versus” as in against, or in contrast to?

Are the two mutually exclusive?

When I think of egg donation and embryo donation, I think about the word “AND” – I don’t think of it as an either or.  Both are just different ways of either growing or adding to your family.

Some approach embryo donation with great trepidation because they worry about the bonding process, or about the explanation or story they will be sharing with their child. The reality is – the path might be different but at the end of the day the goal is the same – you are becoming a parent.

Let’s delve a little deeper.  If you receive a donor egg, the genes of your baby are going to be combined with the genes of your husband (or partner) and those of your egg donor. Or if you are a single mother, or women in a same sex relationship, the donor egg will be combined with donor sperm.  You will probably undergo what we call a fresh embryo transfer.  You will carry that baby for nine months and then deliver that baby.  Women often wonder if there’s a down side to carrying a baby that is not genetically related to them.  You know this is an age old question that’s been asked and answered since the early 80’s when the first donor egg child was conceived, carried, and delivered. I can tell you as a parent via egg donation myself that it doesn’t matter.  I carried my son for nine months.  The bond I created with him is rock solid, loving, and he’s my son. The lack of genetic connection simply doesn’t matter.  Not one iota.  The very same thing happens with embryo donation recipient parents who are receiving truly a meaningful gift of life.

The most beautiful aspect of embryo donation to me is that embryos that are being placed for donation are done so purposely. These are embryos that the donating parents know have created amazing children who are loved, honored and cared for.  These donating parents want to make sure their embryos are donated to a home that will love, cherish and honor the resulting children as they would. Regardless of whether an individual has a child via egg donation or embryo donation, the fears of parenthood almost always focus on the unknowns. And here’s a secret:  they are also experienced by those who are conceived naturally.  Moms and Dads all over the world have the same worries about parenting as do parents via egg donation and embryo donation.

Parents via egg donation often ask questions such as:

• Am I going to screw up my child?
• Will my child love me?
• How am I going to relate to my child?
• Will my parents and other family members accept my child?
• How and when will I share information about their conception?

When we look at embryo donation the questions that we find unique to embryo donation are:

• Are we protected legally, can the donating parents come back and claim our child in the future? (The answer is NO, they cannot.  That’s why it’s important to have a clear legal contract.)
• Will my child have access to information about his or her health in the future?
• Will my child have siblings and if so, will they have the opportunity to know them?
• Will my child or children see me as their real parent?
• How will I explain this to my family or friends?
• What about stupid comments from those around me?
• How and when will I share the information about my child’s conception with my child?

To me there is no difference between being a parent via egg donation or a parent via embryo donation.  The end result is the same.

At the finish line we are simply Mom and Dad.

Marna Gatlin
Parents via Egg Donation
www.PVED.org | marna(at)pved.org

A little bit about Marna…

After many years of struggling with infertility, PVED founder Marna Gatlin discovered that the technology to have a child through egg donation was available. She was curious, excited, and above all, hopeful that this process might be the conduit to finally achieving her lifelong dream of becoming a parent.

Marna ensures that all the needs of egg donor recipients are met, maintaining a high standard of ethics and confidentiality. Marna advocates and assists recipient parents, helping them arrange for the highest quality patient care, wherever in the world they reside. Her experience and knowledge related to the complex emotional and physical needs of individuals dealing with infertility makes her an essential asset PVED.

As a previous recipient, Marna is uniquely qualified to provide caring and timely services. Marna is truly dedicated to compassionately guiding couples experiencing infertility through their treatment process.

Marna is joined by several dedicated and knowledgeable support staff that all work together clearly dedicated to see the success of PVED. These include clinical psychologists, reproductive endocrinologists, attorneys, as well as a talented business and public relations team.

Marna attended Eastern Oregon University and Portland State University majoring in Business, Psychology, Social Science, and is a member of the American Society of Reproductive Medicine (ASRM), the European Society of Human Reproduction and Embryology (ESHRE) and the Society for Assisted Reproductive Technology (SART). Marna, a writer, is married, has a son, and does some of her best thinking and creating atop of her John Deere tractor mowing and cultivating her back forty.

In the first two segments of this series, we discussed embryo grading and cryopreservation (1 – Do these embryos make the grade? and 2 – Embryo Cryopreservation: An Easy to Understand Review). This final segment in the series will examine the process of thawing or warming of embryos for transfer.

In Review…

Let’s begin with a short review of the previous blogs. You will recall that we discussed two methods of embryo cryopreservation, slow freezing and vitrification. Both methods require that the cells of the embryo have as much water removed as possible and that cryoprotectants, materials that protect the cells during freezing, be forced into those cells to reduce ice crystal formation. Slow freezing uses a controlled rate freezing instrument that slowly lowers the temperature to well below freezing to avoid the formation of ice crystals. Vitrification is a method in which embryos are plunged directly into liquid nitrogen and immediately turned into a glass-like substance, essentially cooling the embryos so quickly that ice crystals do not even have time to form.

Cryopreservation Storage Containers

One topic not covered in the freezing blog was the type of containers used to hold the embryos. Slow freezing, in most cases, uses straws or vials to hold the embryos in a small amount of solution called media. Vitrification uses many different storage devices to hold the tiny embryos, which cannot be seen without a microscope. These devices commonly include various types of straws, nylon loops or electron microscope grids, just to name a few.

How Often do the Cryopreserved Embryos Survive?

It is expected that about two-thirds of embryos cryopreserved via a slow freeze technique will survive thawing (Son and Tan, 2009) and the embryos that do not survive are most likely genetically abnormal. For embryos that are vitrified, the rapid cooling/warming process seems to work better, with about 80-90% of the embryos surviving. For this reason, vitrification is becoming more popular for cryopreserving both eggs and embryos.

How Many Embryos Should Be in Each Container?

Ideally only one or two embryos should be packed into each storage container. By packaging one embryo per container, the embryologist can thaw or warm only the exact number of embryos to be transferred without having any left over. For example, if a patient wants to have two thawed cryopreserved embryos transferred and they have a total of five embryos each frozen in separate containers, the embryologist will thaw/warm one container at a time until just two healthy embryos are recovered. If, however, the same five embryos were packaged in two containers with three embryos in one and two in another, the embryologist would probably first begin thawing/warming the container with three embryos. Should all of the embryos survive, there is one excess embryo that would need to be transferred, refrozen or discarded. While recent studies have indicated that freezing embryos a second time can result in a pregnancy, particularly when using vitrification, it is ideal to only thaw the exact number of embryos that we want to transfer and not one embryo more. (Kamasko, Y. et.al., 2009).

How are the Embryos Thawed/Warmed?

Ice crystal formation is also the enemy when thawing embryos, just as when cryopreserving them,. As embryos warm from -196°C (-321°F) toward 0°C (32°F), ice crystals may again form and damage the cells. We use the following techniques to rapidly warm/thaw both slow frozen and vitrified embryos in an attempt to avoid ice crystal formation:

1. For embryos frozen by the slow freeze method, the straws or vials are removed from the storage tank and held at room temperature for 30-60 seconds, allowing the embryos to warm only slightly. The storage container is then plunged into 37°C water, completing the thawing process quickly enough so that the ice crystals don’t have a chance to form.
2. Vitrified embryos are taken out of liquid nitrogen, with the container then plunged directly into warming media that is either at room temperature or 37°C, depending on the method used to vitrify the embryos. Once again, the ice crystals simply do not have enough time to form.

Once the embryos have been thawed/warmed, the cryoprotectants that replaced the water in the cells must be removed and balanced solutions placed back into the cells. To accomplish this, embryos are moved from small bath to small bath with varying concentrations of water and other substances. As the cryoprotectants are removed, the cells fill with water containing the nutrients and growth factors needed for cellular recovery. Once the embryos have been thawed/warmed, they are placed in the incubator in supporting culture media for two to twelve hours to allow the cells to continue equilibration prior to transfer. If we are thawing embryos that were frozen early, we may even grow the embryos for a few days so that we transfer the fewest healthy embryos we need to achieve a successful pregnancy.

Are There Other Factors That Influence the Survival of Cryopreserved Embryos?

While ice crystals play a big role in the survival of embryos, they are far from the only concern. Embryo survival rates vary for many reasons including;

1. Embryo quality: Poor quality embryos freeze and thaw poorly. Poor early development of an embryo suggests that the embryo is in the process of dying and such embryos should probably not be cryopreserved.
2. Freezing media and cryoprotectant “recipes“: Some recipes are potentially better than others and each laboratory has to find which works best. What works well for one, may not be the best for others.
3. Laboratory techniques: Laboratories must have an excellent quality control program to assure they are following the steps involved in freezing/cooling and thawing/warming the cryopreserved embryos precisely.
4. Embryologist variability: As with all techniques that involve humans, some seem to do a better job than others. There is no substitution for careful training and experience.

In Closing…

We hope this series has given you a glimpse of what is involved in grading, freezing/cooling and thawing/warming your precious embryos. Cryopreserved embryos give patients the option to build their families in a cost effective manner. Without cryopreservation, embryo donation would really not be possible.

Corey Burke, B.S, C.L.S.
Laboratory Supervisor
Embryo Donation International
CBurke@EmbryoDonation.com

References:

Kamasko, Y. et.al. The efficacy of the transfer of twice frozen-thawed embryos with the vitrification method.  Fertil Steril 2009;91:383-386.

Son, W.Y., and Tan, S.L. Comparison between slow freezing and vitrification for human embryos. Expert Rev. Med. Devices 2009:6(1),1-7

Why are Embryos Cryopreserved?

Infertility patients invest so much time, effort, money and emotion into each IVF cycle. After the fresh embryos are transferred, about 30-40% of our patients will have excess high quality embryos available for freezing, also known as cryopreservation, to be used for future cycles. Frozen embryo transfers are a cost-effective way to pursue further treatment, regardless of the outcome of the fresh embryo transfer cycle.

Patients are often curious about the methods their laboratory uses to freeze their embryos.   Cryopreservation is a delicate process requiring extensive expertise to prevent damage to the embryos during the freezing and thawing procedures.

Preventing Potential Damage During Freezing

There are three major types of injury that can occur to cells during the cryopreservation procedure (Jain JK, et al., 2006):

• (i) Exposure of cells to ice crystal formation during freezing and/or thawing;
• (ii) Damage to the embryos from the solutions used to prepare the embryos prior to freezing; and
• (iii) Damage to the embryos as water and electrolytes shift in and out of the cells that make up the embryos.
  

  Water being removed from embryos and replaced with "antifreeze".

Damage from ice crystal formation is overcome by removing as much water from within the cells making up the early embryo and replacing it with fluid containing cryoprotectants. To remove the water, embryos are placed in a series of solutions using increasing concentrations of salt to draw the water out of the cells. Once this is accomplished, the embryos are then placed into additional solutions containing the cryoprotectants, which enter the cells taking the place of the water.

Removing the water from the cells is relatively simple while replacing the fluids with cryoprotectants is a bit more difficult and damage to the embryos can occur if not done correctly. Cryoprotectants can be toxic to the embryos, so the cells can only be exposed to them for a very short time before they are frozen. Once the cells have been filled with cryoprotectants, cryopreservation needs to take place fairly rapidly.

Slow Freezing and Vitrification Techniques

The two most common cryopreservation methods used to freeze embryos are slow freezing and vitrification. The slow

Embryos being prepared to be placed in storage container.

freezing method has been around for decades. Slow freezing involves loading the embryos into special straws or vials and placing them in a separate container, which is surrounded by a liquid nitrogen bath. The container controls the rate of temperature drop and freezes the embryos slowly over a few hours, preventing most ice crystal formation. The freezing device lowers the temperature gradually to -38° C. Once the embryos have reached this temperature, the vial or straw is plunged into a bath of liquid nitrogen to reach a final temperature -196°C (-321°F). They will remain at this temperature until they are thawed.

With vitrification, embryos are rapidly cooled to -196°C (-321°F) almost instantly. This instant cooling does not allow ice crystals to form. Vitrification comes from the Latin vitreum, meaning the transformation of a substance to glass. Please note the use of the word “cooling” is used rather than “freezing” when referring to vitrification. Freezing actually involves transitioning a liquid to a solid through crystallization. No crystals are actually formed during vitrification. To understand the difference better, take a look at an ice cube from your freezer. While it is mostly clear, you will notice it is somewhat cloudy due to ice crystal formation and not as clear as glass. Water that is vitrified appears absolutely clear because ice crystals never had the chance to form and a glass-like substance is created.

Vitrification still requires the replacement of water with cryoprotectants but uses a different recipe. In fact, the cryoprotectants used for vitrification are at a higher concentration and potentially even more toxic to the embryos. Once the embryos are exposed to the high concentration cryoprotectants, they must be frozen very rapidly. Whereas the slow freeze process takes place over hours, vitrification takes place over minutes.

Embryos in storage containers ready to go into larger storage tank.

Is One Cryopreservation Technique Better than the Next?

The process of embryo vitrification is relatively new compared to the slow freeze method; however, great advances have been made over the past decade.

There is evidence that vitrification is a slightly better system than slow freezing. In most studies, the embryo survival rates are better for vitrification than the slow freeze technique. A recent study by Kaskar, K. et.al, also showed that the pregnancy rates with vitrified/warmed embryos (64%) were significantly higher than those that were frozen/thawed by the slow freeze techniques (47%). With higher survival rates and higher implantation rates, vitrification is slowly replacing the slow freeze technique, especially for the storage of eggs and embryos.

Success with Re-vitrification

Vitrification may allow embryos to be warmed, re-vitrified, and warmed again with successful pregnancies reported. While the pregnancy rates are somewhat lower that that of embryos vitrified only once, the results are far better than embryos slow frozen, thawed, re-frozen, and thawed yet again. A 2007 study by Kamasko, Y. et.al, showed no significant differences in implantation rates between once vitrified embryos and twice vitrified embryos. The reason this is important is that embryos may be frozen/cooled in groups larger than we want to transfer. For example, if a patient succeeded with a twin pregnancy with two fresh embryos transferred and only wants one frozen embryo transferred for a future child, having two cryopreserved embryos survive that were stored in a single vial would present a problem. In this case, we would possibly transfer more embryos than we wanted to, discard the extra embryo (not at all desired) or refreeze/re-vitrify the extra embryo. Using vitrification, the embryo may indeed survive a second stage of warming for an additional pregnancy in the future.

Your Embryos Are Very Important

As embryologists, we take our responsibilities to care for your cryopreserved embryos very seriously so that you will have the opportunity to use them for future treatment cycles. Rest assured they will be available when you need them, having been cryopreserved with the most state-of-the-art techniques at our disposal.

Thawing/Warming Your Embryos
If you would like to learn about how embryos are thawed/warmed, be sure to watch for our upcoming blog on this topic!

References:
Kaskar, K., et.al. Comparison of clinical outcome of blasocyst vitrification with slow freezing and fresh embryo transfer. Fertil Steril 2010;94:113-114

Jain JK, Paulson RJ. Oocyte cryopreservation. Fertil Steril 2006;86(Suppl 3):1037-46.

Kamasko, Y. et.al. The efficacy of the transfer of twice frozen-thawed embryos with the vitrification method.  Fertil Steril 2009;91:383-386

Embryo Grading Made Easy For Embryo Donors and Embryo Recipients

Part 1 of a 3 part mini-series by Corey Burke, B.S., C.L.S. & Laboratory Supervisor and Reproductive Endocrinologist Craig R. Sweet, M.D.

Embryo grading is an important factor for both donors and recipients. Potential embryo donors want to know if we will accept their embryos for donation since part of our decision is based on the grade of their embryos. Likewise, potential embryo recipients want to know how likely the donated embryos are to survive thawing and if they are of good enough quality to build their family. Part of our estimation of success depends on the grade of the embryos.

We wish this process could be easier since there is no standardized system used in all embryology laboratories to grade embryos. Furthermore, the grading of embryos is somewhat subjective so one embryologist may grade an embryo

Image of a 2PN Day 1 Embryo

somewhat differently than a colleague.

Embryo grading is an imperfect process; poorly graded embryos may occasionally result in ongoing pregnancies and beautiful looking embryos may not implant and grow. Poorer graded embryos will not necessarily result in an abnormal child; they simply seem to implant and grow less frequently.

So, the appearance and grading of an embryo is an imperfect estimate of the quality of the embryo as well as the embryo’s true potential. It is, however, the best way we have to visually estimate the implantation and live birth rate of a given embryo. We will now examine one of the more common methods used to grade embryos.

When are embryos graded and cryopreserved?

Embryos are usually graded and frozen at three specific stages with “Day 0” being the day of retrieval and fertilization:

Embryos cryopreserved immediately after fertilization are confirmed early on Day 1 (the 2PN (pronuclear stage), but aren’t advanced enough to be consistently graded. Freezing embryos on Day 1 is quite infrequent unless we are certain there will not be an embryo transfer. Accordingly, these embryos are rarely sent to EDI for embryo donation.

Grading Day 3 Embryos

Day 3 embryos are graded on cell number, the amount of cellular fragmentation and the symmetry of the embryo.

Cell Number

Most Day 3 embryos will be comprised of 6-10 cells called blastomeres. Embryos with too few blastomeres may not be healthy, so we prefer at least 7-8 at this stage. Embryos with fewer cells may not be healthy growing very slowly or may have stopped growing entirely commonly called “cell block”.

Fragmentation

Fragments may be found in many of the embryos, which are “bits” of cells that break off from a blastomere. We prefer as little fragmentation as possible. Fragmentation is estimated as the percentage of fragmentation volume compared to the total embryo volume and is converted to a letter grade in the following way:

• 0 % = A
• 1-10% = B
• 11-25% = C
• >25% = D

A large amount of fragmentation may be caused by death of one or more of the blastomeres. The higher the fragmentation, the lower the quality of the embryo & letter grade and the less likely that the embryos will survive thawing. Embryos with high fragmentation rates implant less frequently when transferred fresh or when thawed.

Symmetry

Symmetry of the embryo refers to the shape of the individual blastomeres and the overall shape of the embryo. The blastomeres should all be very similar in size and generally round in shape. The scale used to grade symmetry is

• Perfect = A
• Moderately asymmetric = B
• Severely asymmetric = C

Severe blastomere asymmetry (i.e., large and small blastomeres in the same embryo) reflect nuclear/chromosomal and cytoplasmic problems suggesting the embryo is less healthy than desired. There is supporting evidence that blastomere symmetry is important and reflects overall health of the embryo. Interestingly, the overall symmetry of the embryo (round vs. oval) is of uncertain importance with some very “funny looking” embryos resulting in beautiful and healthy children.

Putting it All Together for Day 3 Embryos

For Day 3 embryos, the order of grading is the “number of cells (#c),” “fragmentation grade” and “symmetry grade”. For example:

• 7cAA = 7 cells with no significant fragmentation and perfect symmetry
• 8cBA = 8 cells with 1-10% fragmentation and perfect symmetry
• 6cBB = 6 cells with 1-10% fragmentation and moderate asymmetry.

Grading Day 5 Embryos

More advanced embryos are graded and potentially frozen on Day 5 or Day 6. These are generally described as morula or blastocysts.

Day 5 Morula Embryos

Morula embryos are difficult to grade as the cells combine, forming essentially a ball of cells that can’t really be categorized in any way other than descriptive terms:

• Morula (early)
• Compacting morula (more advanced)

While some facilities only occasionally cryopreserve Day 5 morula embryos, it is thought that the survival and implantation rates of these embryos may be slightly reduced but they are still quite reasonable, suggesting that they should not be discarded. Day 6 morulas are probably delayed in growth or may have stopped growing, may not be viable and are infrequently cryopreserved.

In order to balance the possible reduced implantation rates, it is common that more morula embryos are thawed and transferred in order to achieve success.

Picture of Morula Embryo

Day 5 Blastocyst Embryos

Day 5 blastocyst embryos are the most advanced embryos we see in IVF. These embryos are formed within 24 hour of actual implantation. Trying to grow embryos beyond this point is

A Day 5 Full Blastocyst

technically difficult, as the embryos usually don’t survive. In addition, the window of time for implantation seemingly closes beyond Day 5 or early day 6. For example, transfer on Day 7 will rarely result in implantation. So, it simply makes more sense to transfer and/or freeze blastocysts rather than trying to grow them any further.

Along with descriptive measures, more objective grading is attempted through evaluation of the cellular expansion, the inner cell mass (which eventually becomes the fetus) and the quality of the outer cell mass called the trophectoderm (which eventually forms the membranes and placenta).

Expansion

As the embryo advances in growth, a cavity called the blastocoel fills with fluid. As the cells continue to divide and the fluid collects, the embryo expands and eventually escapes its outer covering called the zona pellucida. The blastomeres continue to group together wherein the individual cell cannot be counted. As the Day 5 embryo expands, differentiates and escapes the outer zona pellucida, the grade increases numerically from 1-5.

Inner Cell Mass (ICM)

As the blastomeres compact to form the inner cell mass (ICM), this early fetal tissue is graded on a A-D scale:

Trophectoderm (TE)

The outer cells of the trophectoderm (TE) also reflect the overall health of the embryo and are graded in an A-D scale.

Putting it All Together for Day 5 Embryos

For Day 5 embryos, the order of grading is “expansion,” “inner cell mass” and “trophectoderm.” For example:

• 1 = Early blastocyst is unable to be easily graded with respect to ICM or TE as these haven’t separated well enough yet.
• 2BB = Blastocyst with partial ICM compaction with loose, large trophectoderm cells
• 3AB = Expanding blastocyst with total compaction of ICM and with loose, large trophectoderm cells
• 4AA = Hatching blastocyst with excellent ICM & trophectoderm cell layers
• 5AA = Fully hatched blastocyst with excellent ICM & trophectoderm cell layers

Day 5 embryos that are graded 4AA and 5AA are some of our favorite embryos.

Summary Comments

Embryology laboratories strive to grow the healthiest embryos they can. Over time, they have adapted different grading techniques so the laboratories can communicate the quality of the embryos to physicians, patients and each other. Not all beautiful embryos will implant or produce a healthy child but they seem to do so more often than others. Not all poorly developing embryos will fail to implant and produce a healthy child but most do not result in live offspring.

At EDI, we try to only accept embryos that are likely to implant so embryos with less than a B rating for any category are infrequently accepted. This is done to assure our recipients that all of the donated embryos we offer are of the highest quality and provided the greatest chance for a successful pregnancy.

This is only one piece of the puzzle as many other factors influence the likelihood for success. Dr. Sweet will cover this topic in the separate blog within the next couple of months.

Also stay tuned to the upcoming blogs regarding how embryos are frozen and thawed and what techniques seem to work the best.

While embryo grading is not a perfect system, we use it to try to predict the overall quality of the embryos and their potential to survive thaw, grow and build a recipient’s family.

Corey Burke. B.S., C.L.S.
Laboratory Supervisor
CBurke@EmbryoDonation.com

Craig R. Sweet, M.D.
Reproductive Endocrinologist
Info@EmbryoDonation.com

References

Racowsky C, Vernon M, Mayer J, Ball GD, Behr B, Pomeroy KO, Wininger D, Gibbons W, Conaghan J, Stern JE. Standardization of grading embryo morphology. Fertil Steril. 2010 Aug;94(3):1152-3.

Beginning next week, we’ll be publishing a mini-series on how embryos are processed in the laboratory. Written by Corey Burke, B.S., C.L.S. & Laboratory Supervisor and Reproductive Endocrinologist Craig R. Sweet, M.D., the three-part series will cover how embryos are initially graded, frozen and finally thawed. The information is designed for patients and written in an easy to understand style.

-Embryo Donation International

Unfortunately, there are far more potential embryo recipients than donated embryos. While in this country alone, hundred of thousands of embryos are stored in liquid nitrogen, (Hoffman DI, et. al, 2003), less than ten percent and frequently less than five percent are donated to patients in need (Klock SC, et al., 2003). As a result, we often have a waiting list of recipients asking for donated embryos.

First, EDI doesn’t discriminate with respect to race, religion, ancestry, sexual preference or marital status. We also try to be fair to existing EDI patients and to those who have yet to become established patients. We basically are looking for potential embryo recipients who have few other reproductive options available. If one views donated embryos as an essentially rationed commodity, we want to make certain that patients in greatest need are ranked the highest. We try to do this in an ethical and fair fashion but ranking them can be a challenge.

While not absolute, below is a general ranking from high priority to lower priority in our general waiting lists:

1. The intended parents have no delivered children and limited financial means with few options available.
2. Their only child died and no other siblings exist.
3. One of the partners raised a child with a different partner.
4. Both of the partners raised children with different partners.
5. Both partners raised one adopted child together.
6. Both partners raised one (genetic) child together.
7. Both partners raised children with other partners and one (genetic) child together.
8. Both partners raised multiple (genetic) children together.

We define a “genetic child” as a child whose genes came from the parents themselves without the use of donated material and also not an adopted child.

Here are some of the questions we also commonly ask in trying to decide where the patients should rank on our waiting lists:

1. How long have they been on the waiting list?
2. Are they established patients with EDI or have never been seen before?
3. Are there other less expensive and viable options such as donor sperm?
4. What have the patients gone through during their infertility journey?
5. Is adoption of a live child a possibility?
6. Are there financial constraints that makes embryo donation far more feasible over other more expensive options?

Also, we actually have multiple lists broken down by the following major categories:

• Type of embryo donation: Anonymous, Approved and Open Embryo Donation
• Marital status/sexual orientation: Single woman, single man (very rare), heterosexual couple (married/unmarried), lesbian couple and gay couple (married/unmarried).

As you can see, the process of ranking can get a bit complicated. Our highest priority is healthy embryo recipients who have never had children of their own and have very few fertility options with limited financial means. For example, this group may include cancer survivors who have been left infertile due to the disease or treatment. In many states, cancer survivors find adoption of a child extraordinarily difficult, so embryo donation may be their only option for building a family. We also tend to rank patients higher who have undergone extensive unsuccessful IVF treatments and egg donation is their only remaining option, but due to financial constraints, are unable to afford the procedure.

While we do not exclude patients who have raised children, some requests come from parents with numerous children in their current family. We are actually not looking for potential embryo recipients who are trying to “save” donated embryos. We wish we had enough embryos for everyone, but until we have more embryos than applicants, we will continue to prioritize patients who have never raised children higher than those who have previously experienced the joys of parenthood. We will not exclude such patients, they will be ranked far lower than others on the priority scale.

While some patients who approach EDI have no children, they may have several other fertility options. For example, a young couple that is infertile due to severe male factor infertility, may best be served with sperm donation. Donor sperm generally is less expensive and faster than embryo donation and they can have more than one child using the same donor. We would prefer to save the donated embryos for patients with few available options.

We hope that our readers will understand our basic goals. For any rationed commodity, we want to save it for those in greatest need. If one pictures the embryos as rare, precious and hard to come by, one can imagine why a fair ranking system must be developed.

Ranking systems are never perfect and often seem unfair to those who receive lower rankings. It is difficult to explain a lower ranking to a patient who is desperately seeking to build or expand their family, however, once separated from the emotional aspect, it is usually agreed that a ranking system is needed to fairly as many patients that we can who are seeking donated embryos.

In summary, we feel that a ranking system is necessary to achieve our goal of matching donated embryos to patients in need in an ethical and fair fashion. In a perfect world, infertility wouldn’t even exist and there would be enough donated embryos to meet the demands of those asking for donated embryos. In today’s realistic world, however, the precious gift of donated embryos is simply not given often enough to meet the demands of those seeking donated embryos. Perhaps someday ,though education and research, the number of patients offering their embryos for donation will increase to such a level that we may be able to eliminate or at least trim back segments of our ranking system. Until that day comes, we will have to do our best to assist in matching patients in need to donated embryos in the most ethical and fair fashion we can.

Shelley Osking, L.P.N.
Embryo Donation Coordinator
Shelley@EmbryoDonation.com

Corey Burke, B.S., C.L.S.
Laboratory Supervisor
CBurke@EmbryoDonation.com

Craig R. Sweet, M.D.
Reproductive Endocrinologist
Founder, Medical and Practice Director
Info@EmbryoDonation.com

Hoffman DI, et al. Cryopreserved embryos in the United States and their availability for research. Fertil Steril 2003;79:1063-9.

Klock SC, et al. The disposition of unused frozen embryos [letter]. N Engl J Med 2001;345(1):69-70.