Weight loss reduces insulin resistance and can therefore improve the symptoms of polycystic ovary syndrome (PCOS) that are associated with insulin resistance (high androgen levels, menstrual irregularity, lack of ovulation and risk factors for type 2 diabetes and cardiovascular disease).

Weight loss is best achieved through a combination of lifestyle changes – ideally diet, physical activity and behavioural change (See Lifestyle Management). In rare instances where it is not possible to achieve weight loss through lifestyle change, weight loss medications or surgery are alternative options.

Weight loss medications

In PCOS, there are a number of small research studies assessing the effect of weight loss drugs (orlistat or sibutramine). These treatments showed similar changes in androgen levels when compared to the oral contraceptive pill or metformin, but greater improvements in some other factors such as weight or insulin. As yet, there is no evidence that these weight loss medications are any better than other medical or lifestyle treatments. They are generally expensive, only work whilst being taken, lead only to small weight loss and have side effects. As such they are not an alternative to improved lifestyle. Sibutramine (sold as Reductil) has been withdrawn from the market in many countries including Australia due to concerns about it increasing the risk of stroke or cardiovascular disease.

Surgical weight loss

There are two main types of weight loss surgery:

• Gastric bypass – where a smaller stomach pouch is made from the stomach and the intestine joined to it (fairly major operation)
• Gastric banding – where the size of the stomach is reduced by a band around the upper part of the stomach (minor procedure done via keyhole surgery)

The effect of obesity surgery has also been assessed in PCOS. While this improves menstrual regularity, natural conception, excess hair (hirsutism), androgen levels and insulin resistance, this is a surgical procedure with potential post-operative complications. As food intake is reduced and food absorption can be affected following surgery, women may be at risk of vitamin and mineral deficiencies such as iron, folate and iodine.  Women are also recommended to not become pregnant until 12-18 months following weight loss surgery. As fertility may improve following weight loss surgery in PCOS, it is important to use appropriate contraception following surgery.

It is also expensive and whilst covered in part by private health insurance, it is very rarely available in public hospitals in Australia.

Weight loss surgery should only be considered for women who fit all of the following criteria:

• Very obese (BMI over 35 with an obesity-related condition such as diabetes, high blood pressure or arthritis)
• Unsuccessful losing weight with alternative treatments

However, for women in these categories, gastric banding does result in sustained and significant weight loss in the majority of those who have the procedure.

Content updated 25 August 2011