George M Grunert MD, Reproductive Endocrinologist, HFS IVF Program Director

Single Embryo Transfer (eSET)

In vitro fertilization (IVF) is a procedure in which the egg and sperm are removed from the body and fertilized in the lab. The resulting embryo is then inserted back into the womb for implantation.

Historically, we could not tell which embryos created at IVF had the chance of resulting in a pregnancy, so multiple embryos were transferred. Approximately 35% of IVF pregnancies were twins and 3-5% were triplets or more. Multiple pregnancy leads to an increased risk of miscarriage and later complications for both the mother and the fetus. The most significant problems, cerebral palsy, neurologic disability, lung and gastrointestinal problems, and even fetal death relate to the increased chance of prematurity in multiple pregnancies.

With the ability to culture embryos to the blastocyst stage, we can select embryos which are more likely to implant and grow. Adding chromosomal testing of the embryo before transfer (PGS, CCS), further increases the chance of pregnancy. This allows us to transfer fewer embryos with an excellent pregnancy rate (<50% per transfer) and minimizes the chance of a multiple pregnancy.

Elective single embryo transfer (eSET) is recommended for all patients who have good quality, chromosomally normal embryos. Transfer of two embryos (dual embryo transfer, DET) only increases the chance of pregnancy slightly, but does not increase the chance of delivery, due to the higher miscarriage and prematurity rates. In fact, if there are two embryos suitable for transfer, the chance of a healthy baby and mother is better transferring one embryo at a time rather than both embryos at once.

The aim of IVF is to achieve a healthy, uncomplicated, singleton pregnancy. Embryo selection followed by eSET allows us to accomplish that.

 

Houston Fertility Specialists Southwest Women&rsquo;s Health Alliance