'Polycystic ovaries are more common in patients who are found to be infertile,' says Ng. 'They were found in 12.2 per cent of more than 200 infertile women by ultrasound,' says Ng.

In Britain, polycystic ovaries are found in 20-30 per cent of women, of whom about half have PCOS. Yet many women know nothing about the condition.

Essentially, it occurs when the ovaries produce more androgens than normal. Androgens are male hormones, but are produced by both sexes and are involved in sexual function. Large amounts of androgens can interfere with egg development and release. In the case of PCOS, some of the eggs develop into cysts, which are fluid-filled sacs.

During a normal menstrual cycle, an egg is released during ovulation. This doesn't occur in women with polycystic ovaries. The cysts build up in the ovaries and may become enlarged.

No one knows the exact cause of PCOS, but it's thought to be related to a problem with insulin.

Insulin is a hormone that controls blood-sugar levels, appetite and fat storage in body cells. It's produced by the pancreas after a meal, allowing body cells to take up glucose, fulfilling energy needs.

Normally, most glucose enters muscle cells and only a small excess is stored in fat cells. With PCOS, the body cells apparently don't respond to normal amounts of insulin, so glucose can't enter the cells. This is called insulin resistance. As a result, the pancreas makes more insulin to try to compensate. Women with PCOS store more fat than normal. High levels of insulin mean an increased risk of developing Type 2 diabetes, being overweight or contracting heart disease. High levels of insulin also stimulate the ovaries to make large amounts of androgens. This prevents ovulation, causing infertility. Although there's no cure for PCOS, Ng says symptoms can be eased with a combination of medication, diet and lifestyle changes.

Wendy Ma, a senior dietician at the University of Hong Kong Space programme agrees. 'Women with PCOS often suffer from obesity. If left untreated, they're at increased risk of Type 2 diabetes, cardiovascular disease (CVD) and cancer,' Ma says. 'The first line of treatment in PCOS is weight reduction, achieved by diet changes and exercise.'

There's now a growing body of evidence suggesting that low glycaemic index (GI) diets can improve insulin resistance and reduce the risk of CVD and diabetes. A review of scientific studies into the optimal diet for women with PCOS published in the British Journal of Nutrition last year found that a modest weight loss of 5-10 per cent brought improvements in ovulation and fertility.

Following a calorie-restricted diet, even without losing weight, has been shown to improve reproductive chances. 'It's still not clear whether low glycaemic index diets are useful for weight reduction,' Ma says. 'However, reducing insulin resistance is a primary goal in the dietary management of this condition. For this reason, a diet low in saturated fats, high in dietary fibre and where most of the carbohydrate foods consumed are low GI is often recommended for this group of women. There's evidence to suggest that these diets will also reduce the risk of CVD and Type 2 diabetes.'

The GI is a measure of the ability of a food to raise blood glucose (sugar) levels after it's been eaten. Low GI foods slowly release sugar into the blood, providing a steady supply of energy, and leaving you feeling satisfied for longer so that you're less likely to snack between meals.

Low GI foods include yams, sweet potatoes, sourdough bread, pumpernickel bread, multigrain bread, linguine, bran, nuts, milk, most fruits and vegetables.

High GI foods cause a rapid but short-lived rise in blood sugar and consequently a surge in insulin. High GI foods have the effect of making you feel hungry and lacking in energy more quickly. Examples of high GI foods include most processed foods such as cornflakes, jasmine rice, baguettes, French fries and doughnuts.

Dietician Gabrielle Tuscher says that people who are overweight should set small goals for dietary changes with a regular exercise regime. 'Focus on decreasing carbohydrates but not cutting them out completely because our bodies use carbohydrates as its main source of energy,' Tuscher says.

Cut out refined carbohydrates such as white breads, cereals, crackers, biscuits, cakes, cookies, pastries, white rice, noodles or pasta. They contain little if any dietary fibre.

Focus on wholegrains, legumes and vegetables as your main carbohydrate source. This includes wholegrain breads and cereals, pitta bread, whole brown rice, red or wild rice, whole wheat pasta or noodles, wholegrain crackers, oatmeal, baked or sweet potato with skin, dark leafy greens, spinach, pak choi, kale, beans, nuts and seeds.

Include lean cuts of protein in the diet (skinless white chicken meat or turkey breast, lean beef or pork tenderloin, veal and lean low-sodium ham). 'Talk to a dietitian or your GP to decide on the appropriate plan for you and to determine an appropriate exercise regime that you can engage in on a daily basis,' Tuscher says.

Several herbal and nutritional supplements have been suggested for treating PCOS, including chromium, glutamine, vitex agnus castus (chasteberry), serenoa serrulata (saw palmetto), angelica sinensis (dong quai), hemp seed oil, fish oils and evening primrose oil.

Herbalists say that some of these supplements may help to promote menstrual regularity, and others may help to treat acne and prevent excess hair growth.

But a lot more research is needed to help understand the management of PCOS. Sharing information about treatment and getting support either through local groups or via internet-based self-help groups has helped Ping understand her diagnosis. She encourages other suffers to do the same.