Abstract

Obesity is associated with altered circulating adipokines, contributing to decreased insulin sensitivity. In pregnancy, adipokines are thought to have a role in the development of third trimester insulin resistance. We hypothesise that obesity in pregnancy is associated with further dysregulation of adipokines.

Fasting plasma samples were obtained from healthy lean (BMI 20-25kg/m²) and morbidly obese (BMI>40kg/m²) pregnant women at 16, 28 and 36 weeks gestation; adipokines were quantified using ELISA. Subcutaneous and omental adipose tissue was obtained from healthy pregnant women (BMI 20.7-48.8kg/m²; n=45) undergoing elective caesarean section at term; transcript levels of adipokines were quantified using qRT-PCR.

Plasma leptin was greater in obese compared with lean women at all three gestations (16 weeks, 54.0±8.9 vs 17.3±2.4ng/mL; 28 weeks, 65.1±7.6 vs 25.9±4.6ng/mL; 36 weeks, 72.7±8.5 vs 24.7±4.5ng/mL, all p<0.001). Plasma leptin increased in obese but not lean women between 16 and 36 weeks (54.0±8.9 vs 72.7±8.5ng/ml, p<0.05). Total plasma adiponectin was significantly greater in lean compared with obese women at 16 weeks only (9.4±1.0 vs 5.8±0.60 µg/mL, p<0.001). Adiponectin decreased between 16 and 28 weeks in lean but not obese women (9.4±1.0 vs 6.1±0.51 µg/mL, p<0.001). There was no significant correlation between BMI and transcript levels of leptin or adiponectin per gram of adipose tissue.

We conclude that in obese pregnant women, there is evidence of further dysregulation of circulating adipokines compared with lean pregnant women. While adipose transcript levels are not different in late pregnancy, greater total adipose mass may contribute to elevated leptin levels in obese women.