Metformin Before Trying to Conceive: What to Know

What does the evidence say about metformin before trying to conceive while trying to conceive?

1. Metformin may improve ovulation and increase the chance of pregnancy in some women with PCOS. 1
2. A meta-analysis found that combining clomiphene with metformin was more effective at achieving ovulation and pregnancy than clomiphene alone in women with PCOS. 2
3. In women with PCOS who conceived on metformin and continued taking it, 1,000 to 2,000 mg a day, throughout pregnancy, research found significantly lower rates of preeclampsia, gestational diabetes, fetal growth restriction, and preterm labor, plus more live births, compared with stopping the medication once pregnancy was confirmed. 2
4. Metformin is not expected to raise the chance of birth defects or miscarriage above the usual background risk, though poorly controlled blood sugar in early pregnancy does raise both risks. 3
5. Whether metformin meaningfully helps male fertility is unsettled: animal research suggests it may protect testicular tissue, but small human studies have had mixed results on testosterone and sperm production, so more human research is needed before it can be recommended for a male partner's fertility specifically. 4

What to know about metformin before trying to conceive while trying to conceive

• If you're already taking metformin for PCOS when you start trying, most guidance is to keep taking it rather than stop, since it may help you ovulate and conceive.
• If you conceive while on metformin, research supports staying on it rather than stopping right away, since continuing has been linked to lower rates of gestational diabetes and preeclampsia than discontinuing.
• If metformin alone hasn't led to pregnancy after several months, ask your provider about adding clomiphene, since that combination has outperformed clomiphene alone for achieving ovulation and pregnancy in research.