Endocrinology: Preconceptional and gestational evaluation of insulin secretion in patients with polycystic ovary syndrome

The relationship between insulinaemia and obesity and glucose tolerance and the impact of pregnancy as risk factor for carbohydrate abnormalities were investigated in 91 consecutive patients with polycystic ovary syndrome (PCOS) aged 26-32 years. Fifteen normoglycaemic patients became pregnant within 6 months of the pregestational study using pharmacological induction of ovulation. Plasma concentrations of insulin and glucose after an oral glucose tolerance test (OGTT) were determined by immunoradiometric assay and glucose oxidase technique respectively. OGTT patients were classified according to their response as normoinsulinaemic (n = 46) or hyperinsulinaemic (n = 45). Impairment of glucose metabolism occurred in 12.1% (n = 11, 10 obese and one lean) of all PCOS subjects. Based on insulin secretion, 6.5% of normoinsulinaemic and 13.3% of hyperinsulinaemic patients had an impaired glucose tolerance and 2.3 and 2.2% respectively a non-insulin-dependent diabetes mellitus. Obese patients had higher values for area under the curve for insulin response to OGTT (I-AUC values) than lean patients, and the percentage above ideal body weight was greater in hyperinsulinaemic than in normoinsulinaemic patients. All hyperinsulinaemic (7/15) subjects who became pregnant developed an impairment of glucose metabolism during pregnancy. It is concluded that the PCOS population was at higher risk of developing carbohydrate abnormalities than the normal population of a similar reproductive age. Furthermore, those with abnormal insulin secretion at the pregestational stage may, during pregnancy, develop an impaired gestational glucose tolerance or gestational diabetes.