Comments: IVF's Solution to Multiple Pregnancies: "Embryo Self-Selection"

Irving News Comments
Copyright November 28, 2004
Reproduced with Permission

"Blastocyst self-selection" is now seen as the IVF industry's new miraculous "solution" to multiple pregnancies. As is usually done, the single-cell human being is sexually reproduced in the IVF lab, and then allowed to grow and develop in vitro. But instead of implanting multiple human embryos in the woman's uterus when they are about 3 days old, the trick is to allow them to continue to develop to the 5-7 day blastocyst stage. In the process, the "best" human embryos will have survived the longer culture period; the "weaker" ones will die off. That is, the human embryos themselves do the "selecting". Since these "best" human embryos are healthy, there is no need to implant more than one or two. As IVF specialist Michael Tucker bluntly puts it, "Simply put, this self selection can be viewed as 'survival of the fittest'". Dr. Tucker specializes in this "survival" technique both at Shady Grove (Maryland -- many faculty affiliated with Georgetown University) and at the Fertility Centers of Chicago (Illinois). Given the thousands of IVF clinics and research labs around the world, one has to wonder how many "less fit" human embryos will meet their Darwinian fate this way, and what other uses there could be for them? Perhaps contributing to "the greater good" at Dr. Tucker's extensive new Chicago IVF research laboratory? Some "solution".

November 28, 2004

The Fertility Network
"Simply put, this self selection can be viewed as 'survival of the fittest'".
Blastocyst Transfer

New IVF Technique Promises to Maximize Safety and Success Rates

Shady Grove Fertility Centers
9707 Medical Center Drive
Suite 230
Rockville, MD 20850
Phone: (301) 340-1188

Blastocyst culture and transfer is a new important technique developed for in vitro fertilization (IVF) that maximizes pregnancy rates while minimizing the risk of multiple pregnancy. The ability to grow embryos for five days to the blastocyst stage of development in the laboratory, rather than the traditional three days, allows clinicians to determine with greater certainty which embryos are really the "best" in terms of their potential for implantation. Consequently, blastocyst culture makes it possible to select the best one or two blastocysts vs. three or four early embryos to transfer back to the mother. This reduces the occurrence of potentially risky multiple births. "Fertility centers like Shady Grove constantly strive to improve IVF success rates through the steady refinements of clinical and laboratory techniques. Clinical blastocyst culture and transfer is the next important step in that evolution," explains Robert Stillman, MD.

What is Blastocyst Culture and Transfer?

Traditionally, embryos have been transferred to the uterus on the second or third day of development after in vitro fertilization and initial embryonic cell division. This day of embryo transfer has been a compromise between maximizing the degree of embryo selection available through longer culture in the IVF Lab versus minimizing the exposure of the embryos to culture media which, in the past, could only sustain growth for 2-3 days.

Michael Tucker, PhD explains, " the dynamic processes of embryo development were not taken into account by the static nature of the "one size fits all" culture media that has been used prior to this point. Because of this, blastocyst growth in vitro had always been suboptimal." New culture media now are designed to take into account the myriad and changing needs of the developing embryo in vitro.

After five days of growth, the cells of the embryo should have divided many times over, and have begun to differentiate by function. The embryos that survive to this stage of development are usually strong, healthy, and robust. They are now called blastocysts. Two important factors had limited the number of embryos that will survive to this stage. First, the inherent "health" of any embryo will dictate its ability to continue to grow and divide. Several eggs may have initially fertilized, but only a few will progress to the four-cell stage, fewer still to the eight-cell stage, and even fewer will develop into blastocysts. Simply put, this self selection can be viewed as "survival of the fittest". The second limiting factor in preventing continued growth of embryos in culture had been the culture media itself. Recently, researchers have identified shortcomings of the in vitro culture environment and have developed new culture solutions called Blastocyst Media. These are rich in life sustaining nutrients that give the embryos every chance to reach there full potential. "From egg collection onward, the embryo will now be exposed to specific media that are designed to meet the nutritional requirements of each stage of development," says Dr. Tucker.

What Are the Benefits of Blastocyst Transfer?

Let's use an example. Historically, if a woman has 15 eggs retrieved, an average of 10 will fertilize by day one of observation. It is impossible to determine at this point which of these 10 are most likely to implant and develop into a baby. Perhaps all will, but perhaps not. On the traditional day of embryo transfer (day three), 5 of the 10 embryos may be developing into vibrant, growing embryos. The others may have slowed or stopped their development altogether.

In this example, we are left with several embryos that still look like they may have excellent potential. Which ones to transfer? Which ones are really the "best"? Two additional days in the blastocyst culture medium allows the natural winnowing process to continue. Thus, after 5 days of growth in the laboratory, only 2 or 3 of the original ten embryos may remain viable. We now know the best embryos to transfer. Embryos transferred at the blastocyst stage have made it through key growth processes and typically offer a greater chance of implanting. Without compromising pregnancy rates, we need only return 1 or 2 blastocysts to the mother instead of the typical 3 to 4 early embryos. In fact, pregnancy rates in the group using blastocyst transfer may even be higher because the uterine lining is more receptive to the advanced embryos. In addition, if there are more than two available at the time of transfer, the remaining blastocysts may be cryopreserved for future use.

A significant benefit of blastocyst culture and transfer is the reduction of high order multiple births that can result from in vitro fertilization. This means that various obstetrical complications that may arise from multiple pregnancies can be minimized. It is especially important in helping patients avoid having to make the difficult personal and ethical decisions regarding selective reduction.

Is Blastocyst Culture and Transfer for Everyone?

In thinking of the example above, patients who have fewer oocytes retrieved, fewer fertilized or fewer dividing embryos by day three in culture have no advantage using blastocyst culture, since little is to be gained in further embryo "self selection". Dr. Stillman emphasizes," Unfortunately the new blastocyst culture media does not improve the health or viability of an individual embryo which is not otherwise able to sustain 5 days of growth and then implant; rather it allows embryos capable of sustained growth to continue in culture and reach their maximum inherent capability."

Helping Patients

In this field of medicine, continued refinements and change offer greater opportunity for infertile couples. Blastocyst culture is the latest important step. " It is exciting for us to be able to offer our patients this promising state-of-the-art technique, as it provides us the ability to further tip the balance of success versus risk in favor of couples when we assist them in their pursuit of parenthood," explains Dr. Stillman. "We are happy to report that the first group of ongoing pregnancies using blastocyst culture and transfer were recently established at the Shady Grove Fertility Centers".

Fertility Centers of Illinois

Blastocyst Culture

During the last 23 years IVF programs have historically transferred a large number of embryos in order to achieve higher pregnancy rates. This has resulted in many high order multiple pregnancies (triplets or more). As a consequence multiple births remain the biggest criticism of the field of Assisted Reproductive Technology today.

An embryo conceived without IVF remains in the fallopian tube for 4 days before entering the uterus and implanting on or about day 6. Ideally embryos created through IVF should therefore be transferred on Day 5. However for the last 10 years IVF embryos transferred on Day 5, after being cultured in conventional growth media, had lower implantation rates than those transferred on Day 3. For this reason the practice had been to transfer embryos into the uterus on Day 3. Implantation rates for Day 3 embryos are only 15% to 20%. To achieve respectable pregnancy rates 3 or more embryos must therefore be transferred whenever possible. This unfortunately dramatically increases the incidence of multiple pregnancies.

Recently refinements in culture media allow embryos to be grown successfully in vitro for 5 days at which time they are referred to as blastocysts. Furthermore the implantation rate of blastocysts approaches 50% in patients 34 years of age and younger. Therefore fewer blastocysts can be transferred while still maintaining high pregnancy rates. By transferring fewer blastocysts the incidence of multiple pregnancy, particularly high order multiple pregnancy falls dramatically.

Currently research continues in an effort to better distinguish between Day 3 embryos that are likely to develop into healthy Day 5 embryos and implant and those that are not as likely to do so. At present the ability to accurately identify these two groups is lacking as evidenced by a recent study done at the Stanford School of Medicine to assess the accuracy of Day 3 criteria in identifying the 2 best embryos to be transferred 2 days later on Day 5. The study involved 100 IVF cycles in which patients were desirous of a Day 5 transfer and was reported in the July 2002 issue of Fertility and Sterility, the journal of the American Society for Reproductive Medicine. Neither Day 3 pick was transferred on Day 5 in 39% of cases, one pick was transferred in 38% of cases and both picks were transferred in only 23% of cases.

It is important to remember that all Day 3 embryos may not survive to the blastocyst stage. Therefore, it is possible that on occasion there may be no embryos available for transfer on Day 5. It is most likely that pregnancy would not have been achieved had those same embryos that failed to develop to blastocysts been transferred 2 days earlier on Day 3.

For the time being, we will encourage blastocyst transfer whenever there are at least 6 or more good quality embryos developing on Day 3. On Day 5 we will then transfer 2 blastocysts. This will minimize the risk of a high order multiple pregnancy while maintaining high pregnancy rates.

Copyright © 2004 - Fertility Center of Illinois

Nadine Sudnick
(630) 231-7649

For Immediate Release

Fertility Centers of Illinois (FCI) Builds New Embryology Lab In Chicago's River North Center To Serve Growing Needs of IVF Patients

One of the nation's leading embryologists heads team to lead lab activities.

February 5, 2004 -- Glenview, IL -- Fertility Centers of Illinois (FCI) announced today the opening of a new In-Vitro Fertilization (IVF) facility to serve the growing needs of IVF patients in the Chicago area. The FCI River North Center is among the nation's most technically advanced laboratory facilities of its kind.

The new lab within the center will feature state-of-the-art equipment, the latest research applications, and a team of highly experienced scientists and professionals who are experts in the diverse areas of embryo science and successful lab operations required for better outcomes.

"Our goal is to provide patients with the most comprehensive, integrated package of infertility support available in the Chicago area," says Aaron Lifchez, M.D. and President, Fertility Centers of Illinois. "What makes this lab unique is that FCI has gathered top-level professionals who have vast experience in applying best practices to the field of IVF. It is the combination of this experience, coupled with all new equipment and facilities, that will offer patients the most progressive solutions for their individual needs."

The River North Center will be directed by Michael Tucker, PhD, a world-renowned embryo scientist. He will be assisted by Juergen Liebermann, PhD, as lab scientific director, who will supervise all scientific protocols in the lab. Joni Stehlik and Ed Stehlik, who have extensive backgrounds in cell biology, cytogenetics, and molecular biology, will supervise daily laboratory operations. The team will also include a seasoned nursing staff, ultrasound techs, and nurse anesthetists who have cared for thousands of patients in other FCI facilities.

"The goal of our new lab is to combine technology, expertise and caring service to deliver healthy, single-embryo transfers to our patients, resulting in better outcomes and reduction of multiple pregnancies," says Dr. Tucker.

River North facility is specifically designed to house high-tech operations and provide services such as back-up emergency power, and has the capability to accommodate future expansion needs. The location is also easily accessible to major highways and other modes of transportation into the city of Chicago. FCI also has another state-of-the-art IVF center located in Highland Park, convenient to patients living in the northern suburbs.

The FCI River North IVF Center is located at 900 N. Kingsbury in Chicago, and patients may schedule appointments by calling (312) 222.8200. Directions to the new lab can also be found on FCI's web site:

Fertility Centers of Illinois

The Fertility Centers of Illinois, S.C., is one of the nation's leading infertility treatment centers, providing advanced reproductive endocrinology services in the Chicago area for over 25 years. The Fertility Centers of Illinois performs over 2,500 IVF (In-Vitro Fertilization) cycles per year and its success rate is recognized among the best in the nation. In addition to a team of nationally recognized reproductive physicians who collaborate to stay current on the latest technology and procedures, FCI patients have access to many other unique support services such as professional counseling from a licensed clinical psychologist, patient advocate services and innovative financial options. FCI's eight offices are conveniently located throughout the Chicago area.

Michael J. Tucker, PhD

Dr. Tucker has over 20 years of experience in this field. He has held several leadership positions at prominent IVF labs in the U.S., such as the Georgia Reproductive Specialists, and Shady Grove Reproductive Science Center in Rockville, MD. Dr. Tucker also serves as an Associate Professor in the OB/GYN Department at the University of Alabama in Birmingham. He has also authored numerous research papers and abstracts as well a colored atlas for human-assisted reproduction. In 2002, AIA (American Infertility Association) awarded Dr. Tucker the "Family Building Award," recognizing his tireless contributions in the community for helping AIA and those affected by infertility.

FAIR USE NOTICE: This may contain copyrighted (©) material the use of which has not always been specifically authorized by the copyright owner. Such material is made available to advance understanding of ecological, political, human rights, economic, democracy, scientific, moral, ethical, and social justice issues, etc. It is believed that this constitutes a 'fair use' of any such copyrighted material as provided for in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C. Section 107, this material is distributed without profit to those who have expressed a prior general interest in receiving similar information for research and educational purposes. For more information go to: If you wish to use copyrighted material for purposes of your own that go beyond 'fair use', you must obtain permission from the copyright owner.