Metformin in fertility treatment

Metformin is a tablet best known for treating type 2 diabetes, but it also has a place in fertility care, mainly for people with PCOS. It works on the body's response to insulin, which is often part of what disrupts ovulation in PCOS. It is not a fertility drug in the usual sense: it treats an underlying driver rather than stimulating the ovaries directly.

Who it is for

Metformin is used mainly in PCOS, especially where there are signs of insulin resistance or a higher body weight. It is sometimes added alongside letrozole or clomiphene when those alone do not produce ovulation, and it is occasionally used within IVF to help lower the risk of OHSS. It does not help ovulation problems that are unrelated to PCOS.

How it works

Metformin improves how the body handles insulin. In PCOS this can lower raised insulin and, with it, some of the raised male hormones that interfere with ovulation, so cycles may become more regular. Its effect builds over weeks rather than days, so it is taken continuously rather than for a few days each cycle.

How well it works

On its own, metformin's effect on pregnancy is modest, and for ovulation in PCOS medicines like letrozole generally work better. Its value is often as a supporting treatment, or for the wider metabolic side of PCOS, and it is frequently paired with changes to diet and activity.

Side effects

The common side effects are digestive: nausea, loose stools, or a general stomach upset. These are most likely early on and often settle, especially if the dose is raised slowly and the tablets are taken with food.

Metformin in India

It is cheap and available almost everywhere, prescribed by gynaecologists and fertility clinics alike. To understand where it fits, read alongside our PCOS page.