Ovarian response – what impact does this have on fertility success after IVF?

This study investigated if ovarian response (OR) has an effect on pregnancy outcomes in patients undergoing in vitro fertilization (IVF).

They found that single embryo transfer (sET) in the blastocyst stage is preferred for all patients

In vitro fertilization (IVF) is a process that involves fertilizing an egg with sperm in the laboratory. The fertilized egg, or embryo, is allowed to develop before the embryo transfer (ET) to the womb. There are many factors to consider during IVF/ET. Embryo maturity (EM) is an important one. Embryos are allowed to develop to a certain stage. This can take up to 5 days. At day 5 (D5), it is called a blastocyst. 

EM can vary depending on the protocol. It is unclear if a certain EM is more likely to achieve pregnancy. The ovarian response (OR) may also have an effect. OR is the term to describe how many eggs the ovary releases when stimulated with hormones. It is unclear if OR is associated with pregnancy outcomes and if EM is an important consideration.

This study included 15,027 IVF/ET cycles. Information on fertility treatment was obtained from a patient database. The authors separated the data depending on the OR. The groups were low (LOR) medium (MOR) and high OR (HOR). The data was further separated depending on EM and embryo number. 1 or 2 day 3 (D3) embryos, or day 5 (D5) embryos (blastocysts) were transferred. The authors compared pregnancy outcomes across the groups. Pregnancy outcomes included implantation rate (IR), clinical pregnancy rate (CPR) and live birth rate (LBR).

LOR patients had lower IR, CPR, and LBR with one D3 embryo compared to 2 D3 or D5 embryos. In the MOR group, the IR was higher with one D5 embryo compared to 2 D3 embryos. There was a lower risk of multiple pregnancies (MPR) in MOR patients that had a D5 blastocyst versus D3. MPR was higher in patients that received 2 embryos in D5 compared to 1 in D5. In HOR patients, IR was lower but the MPR was higher with 2 D3 embryos versus 1 D5 blastocyst.

The authors concluded that sET in D5 (blastocyst) is preferred for all patients.

This was a retrospective study. Some information was not available for analysis. This can affect the results.

If you have any concerns regarding infertility treatment, please consult with your physician.