Can metformin help women with polycystic ovarian syndrome get pregnant?

This article reviewed studies examining the effect metformin (Glucophage) has on women with polycystic ovarian syndrome (PCOS) trying to conceive. The authors found that metformin improved fertility outcomes compared to no treatment in these patients.

PCOS is a disorder that affects women’s hormone levels. This subsequently affects ovulation (the release of an egg for fertilization) and therefore fertility. One of the hormones that is altered by PCOS is insulin. Insulin is the hormone that regulates blood glucose. Women with PCOS often have insulin resistance. This means that the cells no longer respond properly to insulin. This results in high blood glucose and impacts overall health.

Metformin is a drug that improves the body’s response to insulin. Several studies have examined if metformin can improve symptoms of infertility in women with PCOS. However, it is unclear if it helps and if it is a better option than ovulation-stimulating drugs such as clomiphene citrate (Clomiphene; CC).

The results of 41 studies involving 4552 women with PCOS were compared. Participants received either metformin, a placebo, CC or metformin + CC.

Metformin improved symptoms of infertility compared to a placebo treatment. The chances of becoming pregnant increased by 98% after metformin treatment. The chance of a live birth rate (LBR) increased by 59% following metformin treatment. While the LBR following a placebo was 19%, it was between 19 and 37% after metformin. The chance of ovulation increased 2.64 times with metformin treatment.  However, women taking metformin treatment were 4 times more likely to experience gastrointestinal side effects.

The combination of metformin + CC increased the LBR by 27% compared to CC alone. Birth rates after CC treatment were 24% compared to metformin + CC which were between 23 to 34%. The combination of metformin + CC increased the chances for pregnancy by 62% and for ovulation by 65%. Women taking the combined treatment were 4.26 times more likely to experience gastrointestinal side effects compared to CC alone.

It was unclear if metformin was better than CC alone. While obese women with PCOS had a 70% chance of a LBR after metformin, non-obese women had a 71% higher chance. Obese women also had a 66% lower pregnancy rate and a 71% lower ovulation rate with metformin compared to CC. Non-obese women had a 56% higher pregnancy rate with metformin. 

The authors concluded that metformin is a good treatment option for women with PCOS who are trying to conceive, especially those who are non-obese.

Some of the studies used for this analysis were low quality and may have been biased. The studies used also examined different criteria which makes comparisons difficult.