Oral glucose tolerance testing results can help stratify women with gestational diabetes (GD) into groups that predict later risk for prediabetes postpartum, results of a new study showed.

“Clinicians can use these data to identify the women in their practice who are at highest risk of manifesting glucose intolerance after delivery and prioritize them to provide early monitoring and intervention,” said lead study author Erica P. Gunderson, PhD, senior research scientist at Kaiser Permanente Northern California Division of Research and professor of Health Systems Science at Kaiser Permanente Bernard J. Tyson School of Medicine, Pasadena, California.

Such information can be incorporated into the electronic health record, she added. “It would be relatively easy to implement this sort of a tool and automate it into the healthcare system to give practitioners a risk profile for patients based on data.”

“We’ve been using reported information like clinical and family history and parity or demographics. Those are great, but they’re not as sensitive as some of this direct laboratory testing,” she told Medscape Medical News.

GD Linked to Future Risk for Type 2 Diabetes

“We know gestational diabetes is strongly linked to a future risk of type 2 diabetes. We want to prevent that early,” said Gunderson.

Current guidelines call for glucose tolerance retesting of all women with gestational diabetes at 6-9 weeks postpartum, but fewer than half of women receive that testing, the authors noted in the introduction of their study, recently published in JAMA Network Open. Therefore, they wanted to determine what information could improve risk stratification. 

The current study looked at data f rom women enrolled in SWIFT, who were recruited between 2008 and 2011. GD was diagnosed using an initial non-fasted 1-hour 50-g glucose challenge screen, followed by a diagnostic 3-hour 100-g oral glucose tolerance test for those with elevated glycemic results.

The women were divided into three GD subtypes: isolated postload glucose intolerance, fasting hyperglycemia, and a mix of both. 

Women found to have type 2 diabetes at 6-9 weeks were excluded from the analyses to avoid cases of undiagnosed diabetes prior to pregnancy.

A total of 1005 women with GD were included. Study participants had a median age of 33.2 years, and 40.1% had obesity prior to pregnancy. More than a third (36.6%) were Asian, 30.6% were Hispanic, 23.4% were White, and 7.8% were Black.

Overall, 61.3% had isolated postload glucose intolerance, 12.3% had fasting hyperglycemia, and 26.4% had both.

Isolated postload glucose intolerance was found in 67.4% of Asian women vs just 50.0% of Black women; 23.1% of Asian women had both issues vs 41.0% of Black women. In all, 83.8% of women with isolated postload glucose intolerance managed their condition with diet and exercise, while prescriptions of oral medications and insulin were prescribed for 42.7% of those with fasting hyperglycemia and 59.7% of those with both defects.

Prevalence of Prediabetes by GD Subgroup 

The prevalence of prediabetes at 6-9 weeks after delivery was 34.5% overall. By subtype, the proportions were 23.9% for those with isolated postload glucose intolerance, 41.9% for those with fasting hyperglycemia, and 55.8% for those with both.

Compared with the lowest-risk group (those with isolated postload glucose intolerance), the adjusted prevalence ratios for prediabetes in the other two groups were 1.74 and 2.23, respectively (both P <.001). The difference between the intermediate- and higher-risk groups was also significant (1.28; P =.04).

Asked to comment, Aoife M. Egan, MB, PhD, consultant endocrinologist and associate professor of medicine at the Mayo Clinic, Rochester, Minnesota, told Medscape Medical News, “I think overall, it's a great study. There's been a real dearth of studies examining GD in detail. We’re growing in our awareness that GD is a very heterogeneous disease in terms of how it presents, the effects it has on the pregnancy itself, and the long-term risks.”

She added, “I hope that this type of study is going to pave the way for more of a personalized approach for women living with GD.”

Egan noted that the study was done in “a really large cohort” with “mixed race and ethnicity.” Many previous studies have been done just in a White population, he said, “so this is really nice to see.”

Both Gunderson and Egan pointed out that these findings apply only to the two-step method for diagnosing GD in the US. Egan explained that in Europe, where a one-step 75-g test is more commonly used, baseline fasting glycemia is included, “whereas in the US, people can skim through that first test, and it could miss people with an isolated fasting problem.”

Gunderson agreed but noted that the study was based on US practice in “a huge population that is representative of the diversity in the US GD population.”

Risk in Lowest-Risk Group Still About One in Four

While she agreed that the current results open “the door for potentially a stratified approach with more emphasis on the higher risk people, particularly if it’s a resource-limited environment,” Egan pointed out that even among the lowest-risk group, the study showed that the risk for prediabetes was still about one in four. 

“The bottom line is that anybody who develops gestational diabetes still has a substantial risk of postpartum glucose intolerance and would benefit from some intervention,” she told Medscape Medical News.

“I think our biggest challenge now is to develop an approach to postpartum testing that’s actually acceptable to women and ensures that our rates of attendance are higher,” she said.

Gunderson reported receiving grants from the National Institute of Diabetes and Digestive and Kidney Diseases during the conduct of the study, as well as from the National Heart, Lung, and Blood Institute. Egan reported no disclosures.

Miriam E. Tucker is a freelance journalist based in the Washington DC area. She is a regular contributor to Medscape Medical News, with other work appearing in the Washington Post, NPR’s Shots blog, and Diatribe. She is on X @MiriamETucker and BlueSky @miriametucker.bsky.social.