Introduction

Polycystic ovary syndrome (PCOS) is present in approximately 75% of women with infertility due to anovulation and it is frequently diagnosed for the first time in the fertility clinic. The majority of women with anovulation or oligo-ovulation due to PCOS have clinical and/or biochemical evidence of hyperandrogenism. Almost all these women will have a typical ultrasonic appearance of the ovaries.

The exact mechanism causing anovulation associated with PCOS is not known and the excess of small antral follicles, hyperandrogenaemia, hyperinsulinaemia and dysfunctional feedback mechanisms have all been implicated. There are, however, a number of strategies to restore ovulation, most of them reliant on increasing follicle-stimulating hormone (FSH) concentrations, either endogenously or exogenously, or reducing insulin levels. These include medical therapies such as clomifene citrate, aromatase inhibitors, metformin and low-dose gonadotrophin therapy and surgical treatment by laparoscopic ovarian diathermy. This chapter describes treatment with clomifene, aromatase inhibitors and gonadotrophins in detail, but metformin only in brief as it is covered in full in Chapter 15. Laparoscopic ovarian diathermy is discussed in Chapter 14.

Weight loss

Whereas obesity expresses and exaggerates the signs and symptoms of insulin resistance, loss of weight can reverse this process by improving ovarian function and the associated hormonal abnormalities and may alone induce ovulation and pregnancy. Loss of weight induces a reduction of insulin and androgen concentrations and an increase in sex hormone-binding globulin concentrations.