Does progesterone level affect the success of in vitro fertilization?

This study examined whether progesterone levels have an effect on live birth rates in women undergoing in vitro fertilization.

For a successful pregnancy to occur with an assisted reproductive technique such as in vitro fertilization (IVF; the egg is fertilized outside of the body and implanted into the uterus), the uterus must be receptive to the implantation of an embryo. The timing of a receptive uterus is dependent on the hormone progesterone. Therefore, if progesterone levels are too high on the wrong day of an IVF cycle, it has a negative effect on the outcome.

The use of frozen embryos, which can be implanted whenever needed, has made it necessary to further understand the role progesterone plays in the outcome of IVF. Also, the role progesterone plays in the number of eggs available for harvest (also known as the ovarian response), or the success rates of IVF is unclear. The current study examined the association between progesterone levels and live birth rates in women with differing ovarian responses.

4,332 women taking part in their first IVF cycle were included in this study. Patients were categorized as poor ovarian responders (less than 5 eggs available for harvest), intermediate responders (6-19 eggs) or high responders (more than 20 eggs). These three groups were then subdivided into groups based on the level of progesterone at the time of human chorionic gonadotropin administration (the hCG trigger used to stimulate the last stage of egg maturation). The live birth rate was determined for each progesterone level.

The live birth rate was 58.18% overall. For poor ovarian responders, 55% of those with non-elevated progesterone levels had high quality embryos available for transfer, compared to 38.4% of those with elevated progesterone levels. The live birth rate was 12% higher for women with non-elevated progesterone levels, but this difference was not statistically significant.

Intermediate ovarian responders with non-elevated progesterone levels had a significantly higher live birth rate (63.1%) compared to women with elevated progesterone (47.1%). Similarly, high ovarian responders with non-elevated progesterone had a 78.9% live birth rate compared to 57.7% for those with elevated progesterone.

This study concluded that elevated progesterone levels were associated with decreased live birth rates regardless of ovarian response.

However, in this study there were many more women with non-elevated progesterone levels included than those with elevated levels.