PCOS is one of the commonest endocrine disorders, affecting women during their reproductive years. With the advent of ultrasound and the rapid development of new technology, the presence of polycystic ovaries can be now be easily identified.
PCOS is defined as the detection of polycystic ovaries by ultrasound scan in conjunction with symptoms of irregular or absent periods (oligoamenorrhoea), excessive weight gain and hyperandrogenism seen as acne and unwanted hair growth (hirsutism). An ultrasound finding of polycystic ovaries is characterised by enlarged ovaries with more than 10 cysts, 2–8mm in diameter and present around a thickened outer ovarian stroma.
It is estimated that about 20 per cent of women have polycystic ovaries when detected by ultrasound, and that 10 per cent of all women experience a symptom of PCOS at some time. The main clinical problem that women with PCOS encounter is irregular menstrual cycles as a consequence of a failure of ovulation. This results in difficulty in achieving pregnancy, and often requires treatment by a gynaecologist with special training in reproductive medicine.
Hormonal changes can occur. The most typical hormone changes associated with PCOS are raised concentrations in the blood of testosterone, luteinising hormone (LH) and insulin. If menstruation is occurring, measurements should be taken between day two and day six of the cycle. However, about one third of women with PCOS show no hormone abnormality. The simplest picture that explains the syndrome is that the ovary makes an excess of testosterone by one of two mechanisms. The ovary might spontaneously over-produce testosterone with no external driving force, or it might be driven to produce excess testosterone by the action of either LH or insulin. There is now good evidence to confirm an association between PCOS with the development of type-2 diabetes in later life. This is particularly evident in women who have a BMI of more than 30. It is also associated with certain ethnic groups such as the Asian community.
Risk factors for pregnancy include an increase in first trimester miscarriage, especially in those women with a raised basal LH level. For women entering pregnancy with a raised BMI, there is an increased risk of gestational diabetes requiring insulin. If patients with PCOS are amenorrhoeic, it is essential to make sure they have regular withdrawal bleeds at least every three months, because of the effect of their unopposed oestrogen on the endometrium. This will reduce the risk of atypical glandular cells developing within the endometrium and prevent endometrial cancer from occurring. Progesterone such as medroxyprogesterone acetate (Provera) 10mg twice a day for one week can be taken every three months to ensure a withdrawal bleed occurs and avoid the proliferative effect of unopposed oestrogen on the endometrium.