A Missed Diagnosis, a Missed Opportunity

During a recent study of pregnant women in urban slums in India, Dr. Puja Chebrolu’s team trained community health workers to screen for gestational diabetes. The findings surprised everyone: More women tested positive than expected, and many were young, with no obvious risk factors for the disease.

The discovery held unexpected implications for how women are screened in the United States. Dr. Chebrolu’s team had followed the World Health Organization’s standard screening method: After an overnight fast, women have their blood drawn before drinking a sugary solution, then undergo two more blood tests at intervals. In the United States, standard screening for gestational diabetes bypasses the fasting step. Only if a woman’s blood sugar is elevated on a first blood test does she move on to a second, more intensive test that requires fasting.

In most of the Indian women who tested positive for diabetes, indications showed up only after the first blood draw during fasting, before the sugary drink. “These women would have been missed entirely if not for this screening method,” says Dr. Chebrolu, an assistant professor of medicine.

Dr. Chebrolu realized that three out of four of those cases would have slipped by unnoticed under the standard American test for gestational diabetes, which is used in part to save on short-term costs and to avoid overdiagnosing milder cases that may not affect a pregnancy. But it’s never been rigorously studied in nonwhite populations, and she suspected race might play a role in the discrepancy. “It’s known that women of color are disproportionately affected by diabetes,” Dr. Chebrolu says. “And [in the U.S.] we’re using a test that’s not designed to catch them.”

Studies also show that many people of color often have higher baseline insulin resistance — regardless of typical diabetes risk factors like weight and age. Yet researchers haven’t closely examined how that plays out during pregnancy. Dr. Chebrolu set out to close that gap.

With support from the Cornell Center for Health Equity, she launched a pilot study in 2023 in Queens, one of the most ethnically diverse communities in the United States. Early results confirmed the pattern, showing that nonwhite women are about twice as likely to be diagnosed with gestational diabetes when screened using the World Health Organization’s fasting-based test.

This isn’t a minor oversight. “It isn’t just about pregnancy,” Dr. Chebrolu says. “It’s about the woman’s long-term health.” Women with gestational diabetes are up to seven times more likely to develop type 2 diabetes within a decade, facing greater risks of heart attacks and strokes. Their children face elevated lifelong risks as well.

Though the U.S. method is seen as cost-effective, Dr. Chebrolu argues that the long-term toll in health-care costs is far greater. Through a Ritu Banga Healthcare Disparities Research Award, she is studying how screening in pregnancy affects long-term diabetes risk. “If we prevent even 20% of cases,” she says, “we’d still make a huge dent” in the approximately $413 billion the U.S. spends each year in diabetes care.