Background: In well-fed Western populations, insulin resistance and maternal insulin levels rise gradually during pregnancy to support foetal growth. There is a scarcity of data on undernourished women from LMICs. We explored the relationship between offspring birth weight and lipid concentrations and serial glucose-insulin in urban and rural Indian women from early to late pregnancy.
Methods: Women in early pregnancy were recruited from prenatal clinics. Fasting glucose, insulin, cholesterol, and triglyceride levels were tested at 16, 28, and 33 weeks of gestation, and a 75 gm OGTT was conducted at 28 weeks. The prevailing WHO 1999/ IADPSG 2011 criteria were used to diagnose GDM. Demographic and anthropometric information was gathered, and new-borns were measured at birth.
Results: A total of 250 women (155 rural, 95 urban) were enrolled: they were 23 years old, 153 cm tall, and had a BMI of 20.7 kg/m2 at 16 weeks gestation. The study eliminated 34 GDM women (18 of whom were rural). Fasting plasma glucose decreased with increasing gestation in 206 normal glucose tolerant women, although insulin concentrations and HOMA-IR remained constant (51 percent decreased); total and triglyceride and HDL cholesterol concentrations elevated. When compared to rural women, urban women were older, taller, and heavier, with significantly higher glucose, insulin, and HOMA-IR levels; they gained 7 kilograms, while rural women gained 6 kilograms between early and late visits. The average birth weight was 2.8 kilograms, with 39 percent of infants being small for gestational age (SGA) and 1 percent being large for gestational age (LGA). Fasting plasma glucose concentrations and maternal size (BMI, weight, height) were linked with birth weight. HOMA-IR was not shown to be linked on its own.
Conclusion: The insulin resistance of the petite and undernourished Indian women did not increase with increasing gestation. This could offer a fresh explanation for foetal growth limitation in India, as well as its short and long-term consequences, including the risk of diabetes.