Correlation between maternal weight and insulin resistance in second half of pregnancy

BACKGROUND: In pregnancy, routine measurement of maternal weight gives a crude assessment of maternal and foetal well-being. Excess weight gain in pregnancy is related to increased risk for gestational diabetes mellitus (GDM), hypertension in pregnancy and foetal macrosomia. In the Nigerian context, lack of knowledge of pre-pregnancy weight coupled with late booking of women in pregnancy hinders accurate assessment of weight gain in pregnancy. The absolute maternal weight is often used as surrogate. This study evaluates the relationship between absolute weight in the second half of pregnancy and insulin resistance. PATIENTS AND METHODS: The weight of hundred pregnant women was measured between 24 to 32 weeks of pregnancy and their insulin resistance was measured using Homeostatic Model Assessment (HOMA-IR) from fasting serum glucose and fasting serum insulin. RESULTS: Twenty-six women had weight ≥95 kg and 74 women had weight of <95 kg. There was a significant positive correlation between weight and HOMA-IR (r = 0.248), fasting glucose (r = 0.198), and fasting insulin (r = 0.228), (P < 0.05). The mean weight, HOMA-IR, fasting glucose and fasting insulin were higher in women with weight ≥95 kg compared to those with less weight. Also maternal weight ≥ 95 kg was associated with severe insulin resistance, (Odds Ratio = 3.1). CONCLUSION: Absolute weight in pregnancy correlates well with insulin resistance. Women having weight ≥95 kg between 24-32 weeks of gestation were more likely to have severe insulin resistance with implications for increased risk of GDM and other complications.