The polycystic ovary syndrome (PCOS) is a common condition, affecting 10%–15% of women, and is defined by the presence of at least two of the following three criteria (Table 6.1): (1) a menstrual cycle disturbance, that is oligomenorrhoea or amenorrhoea, (2) evidence of hyperandrogenism, as assessed by either physical signs (excess hair growth on the face or body (hirsutism), acne, alopecia) or a biochemical elevation of androgens and/or (3) polycystic ovaries as seen by ultrasound scan, after appropriate endocrine tests have been carried out to rule out other causes of androgen excess and menstrual cycle irregularity. PCOS therefore encompasses many of the natural features experienced by adolescent girls and so it is important to ensure that an appropriate diagnosis is made. Indeed, for this reason, the current guidelines suggest that the diagnosis of PCOS cannot be made until at least 3 years after menarche and some even suggest that one should wait for 8 years, which is when full reproductive maturity has usually been attained.

Assisted conception is associated with a higher risk of multiple pregnancy than natural conception. Both ovulation induction and IVF are associated with a higher risk of multiple pregnancies, but the latter contributes to most of the multiple pregnancies following assisted conception treatment. The adverse obstetric and perinatal outcomes of multiple gestations are amplified if the pregnancy was conceived after infertility treatment. The risk of multiple pregnancy after ovulation induction (with or without intrauterine insemination) appears to be linked to the number of follicles recruited whilst the risk after IVF is related to the number of embryos transferred. Aiming for uni-follicular recruitment reduces the risk of multiple pregnancy following ovulation induction and performing a single embryo transfer in IVF cycles reduces the risk of dizygotic twinning. Some of the laboratory techniques used in IVF such as culture to the blastocyst stage and pre-implantation genetic testing elevate the risk of monozygotic twinning.

In vitro fertilization (IVF) should be viewed as a third-line treatment for those with polycystic ovary syndrome (PCOS). In the absence of known causative factors of infertility, such as tubal or sperm abnormalities, a methodical approach to treatment should first include lifestyle modification and an efficacious trial of ovulation induction (OI). Cumulative pregnancy rates of 62% within 4 treatment cycles have been shown with letrozole, an aromatase inhibitor[1] – now widely accepted as the first-line OI agent in PCOS.[2, 3] For those who remain refractory to different regimens of OI, the move to IVF, with the associated risk of ovarian hyperstimulation syndrome (OHSS), becomes justified. The presence of polycystic ovaries is a major risk factor for OHSS, necessitating careful planning of gonadotropin stimulation.

Human reproduction is the most basic of human functions and is the foundation of our very existence. When considering the bodily mechanisms involved, from the delicacy of the interacting endocrine network to the wonder of the cyclical changes in the ovary and uterus and the mechanism of sperm production, it is a constant source of amazement that the integration needed to produce another human being does not go wrong more often.

Folic acid should be taken at a daily dose of 400 mcg or, in those who are obese, 5 mg. There is debate about the restriction of fertility treatment to women who are overweight, although there is no doubt that obesity has a significant adverse impact on reproductive outcome. It influences not only the chance of conception but also the response to fertility treatment and increases the risk of miscarriage, congenital anomalies and pregnancy complications [1]. The British Fertility Society guidance suggests that treatment should be deferred until the BMI is less than 35 kg/m2, although in those with more time (e.g. less than 37 years, normal ovarian reserve) a weight reduction to a BMI of less than 30 kg/m2 is preferable [2]. Even a moderate weight loss of 5–10% of body weight can be sufficient to restore fertility and improve metabolic parameters.