Insulin-sensitising drugs - metformin
PCOS can increase the body's resistance to insulin, leading to the body producing excessively high levels 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 drug known as an 'insulin-sensitising agent', which lowers the blood sugar level, in turn reducing the excessively high insulin.
There is now a body of research about metformin use in PCOS, but unfortunately it is still difficult to generalise about its exact role. Some things we do know about metformin:
- Up until 2004, the studies showed that metformin alone improved menstrual cycle regularity for some women, but it remained unclear as to whether this translated into a higher 'take home baby' rate - which is what is actually important if you are taking it for infertility
- The effect of metformin on hirsutism and weight loss has not been found to be substantial if it does have any effect at all.
- Metformin and clomifene combined work better than each drug alone for ovulation induction, so if one drug does not result in ovulation, it may be worth adding the other.
- In 2006 the largest study to date looking at metformin for PCOS found that metformin had no extra benefit over and above lifestyle changes (diet and exercise) alone, in terms of ovulation or weight loss. Also, there was no change in lipid profiles or testosterone levels. However, the average weight of women in this particular study was higher than in earlier studies (body mass index 38 vs 31). It is known that metformin works less well for women who are very overweight, so it may be that this explains the lack of effect seen here.
As you can see, metformin may or may not have a role in helping women with PCOS, but the most important thing to take away is that whether they had metformin or not, women who lost weight through diet and exercise experienced the most benefit. This has been a consistent finding in all research about PCOS.
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