Terminology Tuesdays: Responsible Embryo Transferring

Today I answer some questions about the appropriate number of embryos to transfer during an IVF cycle.

Q- Why is it important to avoid getting pregnant with high order multiples?

A- The goal of any infertility treatment is the delivery of a healthy baby. As more couples receive infertility therapy through assisted reproductive technologies, there has also been an increase in the number of multiple pregnancies (twins) and high-order multiple pregnancies (triplets and greater). This dramatic increase in the number of multiples delivered in the U.S. over the last few decades can be directly attributed to the increase in fertility treatments.

Many couples who struggle with infertility welcome any pregnancy, including twins. However, most of these couples often do not realize that twins and high order multiple gestations (triplets and higher) have an increased risk of both maternal and fetal complications.

The most common complications associated with multiples are the increased incidences of preterm labor and preterm delivery. Prematurity can lead to an increase risk of respiratory distress syndrome, intraventricular hemorrhage, necrotizing enterocolitis, or retinopathy of prematurity.

Additionally, the rate of fetal death rises with multiples, even after birth. With singletons, the rate is 4.3 per 1000 pregnancies. The rate increases to 15.5 per 1000 for twins and 21 per 1000 for triplets.

Lastly, a multi-fetal pregnancy can be a more difficult pregnancy on the mother by leading to an increased risk for developing nausea, gestational diabetes, pre-eclampsia (high blood pressure), and a need for a cesarean section delivery.

Q- What is Responsible Embryo Transferring and why is it important?

A – The best way to reduce the incidence of women conceiving with multiples in an IVF cycle is to limit the number of embryos transferred at the time of the uterine embryo transfer. Reducing the incidence of multiples in an IVF cycle through responsible embryo transferring is important to avoid the associated risks to both the fetuses and mother.

The goal of responsible embryo transferring is to be able to maintain high pregnancy rates while limiting the number of embryos transferred. Elective single embryo transfers are now commonly offered to good candidate patients who have high quality embryos.

Q – How is the number of embryos to be transferred decided?

A- The American Society for Reproductive Medicine (ASRM), and the Society for Assisted Reproductive Technology (SART), the two leading infertility societies in the United States have jointly published guidelines on the number of embryos that should be transferred back into the woman at the time of uterine embryo transfer. These guidelines are based upon strict criteria such as the age of the woman and the health of the embryos.

The guidelines were revised in 2009 to clarify that while exceptions may be allowable for patients with a less favorable prognosis, those exceptions are quite limited. Additionally, regardless of prognosis, only one more embryo than called for in the guidelines should be transferred.

Ultimately, deciding on the appropriate number of embryos to transfer should be a team effort. The couple, embryologists, and physician should all discuss the guidelines and 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 recommended to be transferred is the right number for you.

Source: Fertility and Sterility, Volume 90, Issue 5, Page S163-4, November 2008, Authors: The Practice Committee of the Society for Assisted Reproductive Technology and the 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.