Increased prevalence of gestational diabetes mellitus among women with diagnosed polycystic ovary syndrome: a population-based study.

G estational diabetes mellitus (GDM), defined as carbohydrate intolerance at onset of pregnancy (or first recognition), affects 4–7% of pregnancies overall (1–6). Common risk factors include nonwhite race/ethnicity, older age, obesity, and prior GDM (3–7). Other conditions predisposing to glucose intolerance might also increase the risk of GDM. Polycystic ovary syndrome (PCOS) is a reproductive condition characterized by chronic anovulation, insulin resistance, and androgen excess (8 –10). Affected women have an increased risk of glucose intolerance and type 2 diabetes (11–14). Some, but not all, studies suggest the risk of GDM is higher among PCOS versus non-PCOS women (15–18), and several studies note an increased prevalence of polycystic ovarian morphology and symptoms in women with prior GDM (19–21). This study examines the prevalence and association of PCOS and GDM among a large multiethnic population of pregnant women in northern California.