I hear this question every day. Having suffered from infertility and knowing firsthand the anxiety associated with the possibility of a failed IVF attempt (and the possibility of not realizing the dream of parenthood), I understand why a patient may ask me to transfer more embryos than recommended. Transferring more embryos than recommended leads to an increased chance of multiple gestations (twins, triplets, and more). High order multiple gestations (triplets and greater) is a highly undesirable outcome as these pregnancies lead to an increased risk of complications both for the fetuses and the mother. At Dallas IVF, our goal is one healthy baby at a time. However, knowing just how many embryos to transfer to get one baby is not always easy to discover.
In an effort to maintain high success rates but minimize the incidence of high-order multiple gestations, the Practice Committees of the Society for Assisted Reproductive Technologies and the American Society for Reproductive Medicine published guidelines to assist ART programs and patients in determining the appropriate number of cleavage-stage (usually 2 or 3 days after fertilization) embryos or blastocysts (usually 5 or 6 days after fertilization) to transfer. The Practice Committees go on to state that the guidelines may be modified, according to individual clinical conditions, including patient age, embryo quality, the opportunity for cryopreservation, and as clinical experience with newer techniques accumulates.
Ultimately, deciding on the appropriate number of embryos to transfer should be a team effort. The couple, embryologists, and physician should all discuss what may be the best number of embryos to transfer to increase the chance of success but decrease the chance of multiple gestations. So, I encourage you to ask your doctor if the number of embryos to be transferred is the right number for you.
The following are guidelines published by the Practice Committees of SART and ASRM for deciding upon the appropriate number of embryos to transfer:
A. For patients under the age of 35 who have a more favorable prognosis*, consideration should be given to transferring only a single embryo. All others in this age group should have no more than 2 embryos (cleavage-stage or blastocyst) transferred in the absence of extraordinary circumstances.
B. For patients between 35 and 37 years of age who have a more favorable prognosis, no more than 2 cleavage-stage embryos should be transferred. All others in this age group should have no more than 3 cleavage-stage embryos transferred. If extended culture is performed, no more than 2 blastocysts should be transferred to women in this age group.
C. For patients between 38 and 40 years of age who have a more favorable prognosis, no more than 3 cleavage-stage embryos or more than 2 blastocysts should be transferred. All others in this age group should have no more than 4 cleavage-stage embryos or 3 blastocysts transferred.
D. For patients greater than 40 years of age, no more than 5 cleavage-stage embryos or 3 blastocyts should be transferred.
E. For patients with 2 or more previous failed IVF cycles or a less favorable prognosis, additional embryos may be transferred according to individual circumstances after appropriate consultation.
F. In donor egg cycles, the age of the donor should be used to determine the appropriate number of embryos to transfer.
*Favorable prognosis = 1. first cycle of in vitro fertilization (IVF), 2. good quality embryos as judged by morphologic criteria, and 3. excess of embryos of sufficient quality to warrant cryopreservation
Source: Fertility and Sterility, Volume 90, Issue 5, Page S163-4, November 2008, Authors: Practice Committee of the American Society for Reproductive Medicine.
Dr. Lowell T. Ku, M.D. is a leading Reproductive Endocrinology and Infertility specialist at Dallas IVF, one the nation’s premiere infertility centers. Dr. Ku clarifies the many confusing terms used in the world of Infertility using straightforward explanations.