Does the dose of gonadotropin hormone influence IVF outcomes?

This study looked at the dose of gonadotropin (GN) used for ovarian stimulation during in vitro fertilization (IVF). It found that cycles with higher GN doses may have lower birth rates.

The first stage of the infertility treatment IVF is to stimulate the ovaries to produce multiple follicles. This is most often done using injections of GN hormones. The dose of GN used is specific to each patient. Too low a dose will result in not enough oocytes. Too high a dose leads to ovarian hyperstimulation syndrome (OHSS), which is painful and can have serious complications. Fertility specialists predict the best dose for each patient based on her age, cause of infertility, and response to previous ovarian stimulation.

GN may also have negative effects on fertility. It can cause changes in the lining of the uterus which makes it less receptive to an embryo implanting. High doses can also trigger changes to the follicle which normally occur after ovulation. It is unclear whether the dose of GN affects IVF outcomes.

This study used records of 14,866 fresh IVF cycles where a single embryo was transferred. It also included 2,964 cycles were all embryos were frozen. All of the cycles used GN for ovarian stimulation. They also used GnRH antagonists to reduce the body’s own reproductive hormones. The total dose of GN was compared to the birth rate.

In fresh cycles, lower doses of GN resulted in live birth significantly more often. Low doses (below 2000 IU) had a 27% higher chance of live birth than high doses (above 5000 IU). Frozen cycles also had a trend toward more births with lower doses.

This study found that lower doses of GN are linked to higher IVF birth rates.

Patients’ doctors may have had additional information about their health history which was not adjusted for. Patients with lower expected fertility are typically given higher doses of GN.