Gestational diabetes: A multi-city study carried out across seven antenatal clinics and involving over 3,000 women has found that early gestational diabetes mellitus (GDM) may affect around one in five pregnant women and could signal a higher long-term risk of developing diabetes, compared to GDM that appears later in pregnancy.
The findings come from the STRiDE study, which tracked pregnant women attending clinics in Chennai, Hyderabad and Puducherry and were published in Diabetes Research and Clinical Practice. Researchers reported that early GDM was detected in 21.5% of women, while late GDM was seen in 19.5%, showing that both categories are occurring at significant rates.
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Gestational diabetes is defined as glucose intolerance first identified during pregnancy. It is typically diagnosed at 24–28 weeks of pregnancy, often referred to as late GDM. When detected before 20 weeks, it is classified as early GDM. In the STRiDE analysis, women were grouped as early GDM if their fasting blood sugar fell between 92 and 125 mg/dl, while late GDM was identified when early fasting readings were lower but diabetes was picked up later during the standard mid-pregnancy testing window.
The study’s broader goal was to develop a risk scoring system that could help predict late GDM early in pregnancy. Participants underwent screening before 16 weeks using fasting plasma glucose (FPG) and HbA1c, a measure of average blood sugar over the previous three months. Those with higher values were followed up and tested again at 24–28 weeks.
Researchers also identified differences in risk patterns. Women with early GDM were more likely to have higher early-pregnancy weight, BMI, waist circumference, blood pressure and HbA1c, along with a greater history of GDM in earlier pregnancies and a family history of GDM. Late GDM, meanwhile, showed a stronger link with a family history of diabetes.
Experts involved in the work said the findings highlight the need to refine how India screens and manages GDM. V. Mohan, one of the authors and chairman of the Madras Diabetes Research Foundation, said further research is needed to determine the best timing for testing, the most suitable screening tests, and treatment approaches that improve outcomes while reducing risks for both mother and baby.
He also noted that screening practices differ globally. In many Western settings, testing is focused mainly on women considered high-risk, such as those with a strong family history. In India, however, the burden of GDM is estimated to be three to four times higher, making wider preparedness and earlier detection more important. Researchers said genomic and genetic studies are also being planned to better understand the higher risk in Indian populations.