Cochrane: Metformin during ovulation induction with gonadotrophins in women with polycystic ovary syndrome

abstract:
Metformin during ovulation induction with gonadotrophins followed by timed intercourse or intrauterine insemination for subfertility associated with polycystic ovary syndrome - The Cochrane Library

Plain language summary

Metformin during ovulation induction with gonadotrophins in women with polycystic ovary syndrome

Review question: Cochrane review authors wanted to find out whether the addition of metformin increases the effectiveness of ovulation induction with gonadotrophins.
Background: Women with polycystic ovary syndrome (PCOS) have reduced pregnancy chances caused by absence of or reduction in ovulation requiring medical treatment. About 80% of women will ovulate on clomiphene citrate, and 50% will become pregnant. Remaining women may take gonadotrophins - hormones that act on the ovaries to stimulate ovulation. The association between insulin resistance and anovulation has led to the hypothesis that addition of metformin might increase the effectiveness of ovulation induction.
Study characteristics: We included five randomised controlled trials of women with PCOS undergoing gonadotrophin treatment for ovulation induction. This review of trials compared metformin or placebo added to gonadotrophins for ovulation induction. Evidence is current to July 2016.

Key results: We were able to include only five trials with a total of 264 women. We graded the quality of the evidence as low. We found no evidence of a difference in risk of multiple pregnancy between metformin and placebo, but we noted higher rates of live birth, ongoing pregnancy and clinical pregnancy with metformin.
Quality of the evidence: Evidence was of low quality for live birth, ongoing pregnancy, clinical pregnancy and multiple pregnancy. Limitations of the evidence included inadequate reporting of study methods and blinding of participants and outcome assessors.