Obesity’s Influence on Insulin Resistance in Pregnant Women with Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine metabolic disorder that is associated with high insulin resistance and obesity. However, ~70% of women with PCOS in Japan are non-obese. We retrospectively analyzed the cases of 163 Japanese women with PCOS who visited our Ob/Gyn department in 2006-2018 to determine which has a greater effect on insulin resistance: PCOS or obesity. We reviewed the women’s medical records and calculated their insulin resistance and insulin secretion. The women’s mean age and pre-pregnancy body mass index (BMI) were 30 ± 5.8 years and 24.8 ± 5.6 kg/m2, respectively; their mean±SD fasting plasma glucose, 94.1 ± 13.7 mg/dL; HOMA-IR, 2.1 ± 2.0; QUICKI, 0.4 ± 0.0; and HOMA-β, 108.9 ± 88.0%. Sixty-eight women were pregnant, and 37% (n = 25) were obese (BMI ≥ 25 kg/m2 ). Obesity had a greater effect on insulin resistance: fasting plasma glucose F(1, 53) = 6.134, p< 0.05; fasting insulin F(1, 53) = 31.606, p< 0.01; HOMA-IR F(1, 53) = 31.670, p< 0.01; QUICKI F(1, 53) = 16.156, p< 0.01. There was no significant difference in values other than QUICKI and testosterone between the women with and without PCOS. Obesity thus had a greater effect on increased insulin resistance in pregnant women with PCOS. Further studies of the insulin resistance of non-obese women with PCOS is needed, as non-obese women with PCOS are common in Asia.