PCOS is arguably one of the most common endocrine disorders in women of reproductive age, affecting 5% to 10% of women worldwide. This familial disorder appears to be inherited as a complex genetic trait (13). It is characterized by a combination of hyperandrogenism (either clinical or biochemical), chronic anovulation, and polycystic ovaries. It is frequently associated with insulin resistance and obesity (14). PCOS receives considerable attention because of its high prevalence and possible reproductive, metabolic, and cardiovascular consequences. It is the most common cause of hyperandrogenism, hirsutism, and anovulatory infertility in developed countries (15,16). The association of amenorrhea with bilateral polycystic ovaries and obesity was first described in 1935 by Stein and Leventhal (17). Its genetic origins are likely polygenic and/or multifactorial (18).
Diagnostic Criteria In an international conference on PCOS organized by the National Institutes of Health (NIH) in 1990, diagnostic criteria for PCOS were based on consensus rather than clinical trial evidence. Their diagnostic criteria recommended clinical and/or biochemical evidence of hyperandrogenism, chronic anovulation, and exclusion of other known disorders. These criteria were an important initial step in standardizing diagnosis and led to a number of landmark randomized clinical trials in PCOS (19).
Since the 1990 NIH-sponsored PCOS conference, evolving perception is that the syndrome may constitute a broader spectrum of signs and symptoms of ovarian dysfunction than those set forth in the original NIH diagnostic criteria. The 2003 Rotterdam Consensus Workshop concluded that PCOS is a syndrome of ovarian dysfunction along with the cardinal features hyperandrogenism and polycystic ovary (PCO) morphology (Table 31.4).
It is recognized that women with regular cycles, hyperandrogenism, and PCO morphology may be part of the syndrome. Some women with the syndrome will have PCO morphology without clinical evidence of androgen excess, but will display evidence of ovarian dysfunction with irregular cycles. In this new schema, PCOS remains a diagnosis of exclusion with the need to rule out other disorders that mimic the PCOS phenotype (19).
Using the Rotterdam PCOS Diagnostic Criteria, the presence of two of the three criteria is sufficient to diagnosis PCOS: menstrual cycle anomalies (amenorrhoea, oligomenorrhea), clinical and/or biochemical hyperandrogenism, and/or the ultrasound appearance of polycystic ovaries after all other diagnoses are ruled out. Other pathologies that can result in a POCS phenotype include AOAH, adrenal or ovarian neoplasm, Cushing syndrome, hypo-or hypergonadotropic disorders, hyperprolactinemia, and thyroid disease (Fig. 31.4).
All other frequently encountered manifestations offer less consistent findings and therefore qualify only as minor diagnostic criteria for PCOS. They include elevated LH-to-FSH (follicle-stimulating hormone) ratio, insulin resistance, perimenarchal onset of hirsutism, and obesity.
Clinical hyperandrogenism includes hirsutism, male pattern alopecia, and acne (19). Hirsutism occurs in approximately 70% of patients with PCOS in the United States and in only 10% to 20% of patients with PCOS in Japan (20,21). A likely explanation for this discrepancy is the genetically determined differences in skin 5α-reductase activity (22,23).
Nonclassic adrenal hyperplasia and PCOS may present with similar clinical features. It is important to measure the basal follicular phase 17-hydroxyprogesterone level in all women presenting
Table 31.4 Revised Diagnostic Criteria of Polycystic Ovary Syndrome 1.
2.