This page will answer some of the questions you may have about the medication (metformin) you have been advised to take to help with your condition of polycystic ovaries (PCOS).

What is PCOS?

PCOS can lead to a resistance to insulin. This means that your body will produce very high levels of insulin in an attempt to compensate. This higher level of insulin is known to cause abnormal cholesterol and lipid levels, obesity, irregular periods, higher levels of androgens, infertility due to disturbance of ovulation and an increased likelihood of diabetes.

Metformin is a type of medication known as an insulin sensitising agent, which lowers the blood sugar level and reduces the high insulin level. It is possible that metformin has a long-term benefit for general health.

Benefits of taking metformin

The few studies that have been carried out and published suggest that metformin may be useful in several areas in the treatment for PCOS.

  • Improving irregular periods (70%)
  • Normalising blood cholesterol
  • Leading to ovulation

About 35 in every 100 women taking metformin achieved ovulation, and when combined with clomiphene (an ovulation inducing agent) it was as high as 90 in every 100 women.


Your consultant will suggest you take 500mg a day. The tablet should be taken with food.

After 2 weeks, it is usual to increase the dose to twice a day and then to 3 times a day after another 2 weeks. This will be discussed with you.

Side effects

In about 25 in every 100 women, metformin causes side effects which may include diarrhoea, metallic taste, nausea, vomiting and abdominal bloating.

We will ask you to eat a calorie-controlled diet while taking this medication.

Blood levels of vitamin B12 can decrease in women who take metformin. This does not usually cause any health problems but we recommend that you take a daily multiple-vitamin supplement.

You may need to temporarily stop taking metformin before major surgery or other medical procedures, such as X-rays that use contrast dyes. Please talk to your hospital doctor about this before any surgery or procedure takes place.

Metformin should be avoided during pregnancy and if you suspect that you are pregnant. The medication should be stopped if a pregnancy is confirmed. Please contact your consultant if you have any questions.

Contact information

If you have any questions, please feel free to contact the fertility nurses through Mrs K Reddy’s secretary on the number below.

Alternatively, contact your consultant’s secretary.

Cotswold Fertility Unit

Tel: 0300 422 3128

Monday to Friday, 8:00am to 4:00pm


Printable version of this page

The use of metformin in Polycystic Ovaries GHPI0467_04_24 Department: Gynaecology Review due: April 2027 PDF, 308.6 KB, 3 pages
Reference number GHPI0467_04_24
Department Gynaecology
Review due April 2027