New study shows gestational diabetes can start in first trimester; What every mother needs to know

Chennai: New research from India suggests gestational diabetes (GDM) may develop much earlier in pregnancy than previously believed – even during the first trimester. This revelation comes from two major studies involving Dr. V Mohan and a team of national and international experts, highlighting the importance of early screening for women and their babies.

Traditionally, GDM is tested for between 24 and 28 weeks of pregnancy. However, the studies introduce the concept of Early GDM (EGDM) for cases detected in the first trimester, while later-onset cases are classified as Late GDM (LGDM).

What do the studies reveal about GDM in India?

The ICMR–INDIAB Study, a national survey of 1,032 pregnant women across India, reported a GDM prevalence of 22.4%, with early GDM at 19.2% and late GDM at 23.4%. Interestingly, the research showed no major urban-rural divide, although Central India had the highest GDM prevalence at 32.9%. This study, published in the Indian Journal of Medical Research, is the first to report prevalence rates for both EGDM and LGDM across the country.

Meanwhile, the STRiDE study (STratification of Risk of Diabetes in Early Pregnancy) involved 3,070 women from seven Indian clinics, the UK, and Kenya, all recruited before 16 weeks of gestation. Findings showed early GDM prevalence at 21.5% and late GDM at 19.5%. The study also found that women with a previous history of GDM were more likely to develop early GDM, while a family history of diabetes was linked to late GDM.

Women with early GDM had higher BMI, elevated HbA1c, and a prior GDM history, underlining the importance of early screening, particularly in South Asian populations.

Why does this matter for mothers and babies?

Dr. V. Mohan, Principal Investigator of the ICMR-INDIAB study and Chairman of the Madras Diabetes Research Foundation, said, “Our data marks a pivotal moment in understanding gestational diabetes in India. The high prevalence of EGDM across diverse regions underscores the urgent need to implement universal screening protocols starting from the first trimester to safeguard maternal and child health.”

Prof. Ponnusamy Saravanan, lead author of STRiDE from the University of Warwick, added that South Asians show higher rates of both general and early GDM. He explained that the STRiDE risk score can help predict GDM and allow timely interventions.

“With nearly one in four pregnant women affected, we are seeing an epidemic that impacts pregnancy outcomes and future diabetes burden. Early detection and region-specific strategies are key,” Dr. R.M. Anjana, Co-Principal Investigator of ICMR-INDIAB, highlighted the wider implications.

Dr. Uma Ram, Senior Obstetrician in Chennai and co-author on both studies, noted that early screening and integrated antenatal care could significantly reduce complications such as preterm birth, neonatal hypoglycaemia, and long-term type 2 diabetes risks.

“Women from lower socioeconomic groups, despite lower BMI, had higher EGDM prevalence, pointing to unexplored environmental or genetic factors,” Dr. Deepa Mohan, STRiDE co-author and epidemiologist, pointed out.

Dr. V. Mohan also stressed the need for clear guidelines, saying, “We now need clear guidelines on screening and treatment of early GDM. The International Diabetes Federation (IDF) is currently developing global recommendations. Early and late GDM management can improve outcomes for both mother and child.”

Dr. V. Mohan has recently been appointed Chairman of the International Diabetes Federation (IDF) Working Group on Diabetes in Pregnancy, recognising his work in gestational diabetes research. In this role, he will collaborate with international experts to help shape global guidelines, ensuring early and effective management of GDM for women worldwide.