Gestational Diabetes Makes Achieving Glycemic Control More Difficult Following Pregnancy

Teresa Janevic, PhD, MPH
Credit: LinkedIn

New research from an Icahn Mount Sinai-led team suggests women who develop diabetes after pregnancy were less likely to regain glycemic control if they had gestational diabetes.

Using a novel population-based cohort, results of the study, which included data from more than 330,000 postpartum women in New York City, suggest women were significantly less likely to regain glycemic control if they had experienced gestational diabetes during their pregnancy, with this impact most apparent in women who were Black or Hispanic.¹

“This study shows that a history of gestational diabetes is a red flag for higher risk of diabetes but also poorer control down the line, with Black and Hispanic women most affected,” said senior investigator Teresa Janevic, PhD, MPH, associate professor of Obstetrics, Gynecology and Reproductive Science, Population Health Science and Policy, and Global Health and Health Systems Design at Icahn Mount Sinai.² “The good news is this red flag provides the opportunity for diabetes prevention, if we focus more intently on mom’s health in the first year postpartum.”

As a result of the rising prevalence in the US and abroad, maternal diabetes has been thrust into the spotlight as a focal point for medical research and management strategies in real-world practice. Citing a lack of research into racial/ethnic-specific estimates of the influence of gestational diabetes mellitus in type 2 diabetes, Janevic and colleagues from Icahn Mount Sinai sought to outline these trends among a cohort of women who gave birth in New York City from 2009-2011.¹

With this in mind, investigators designed the current study as an analysis of data from the NYC A1C Registry, which provided data related to a final birth cohort of 336,276 women. Launched by the New York City Board of Health in 2005, the NYC A1C Registry established a population-based registry to track the level of glycemic control in people with diabetes through mandating laboratory reporting of HbA1c laboratory test results.³

The specific population identified for inclusion were required to be free from diabetes at baseline and gave birth between 2009 and 2011. For the purpose of analysis, investigators considered diabetes onset post-pregnancy as at least 2 HbA1c tests of 6.5% or greater from 12 weeks postpartum onward. Investigators defined glucose control as the first test following diagnosis with an HbA1c less than 7%.¹

Investigators pointed out Cox regression with a time-varying exposure was used to assess the effect of gestational diabetes on time to diabetes onset and glucose control, with stratification according to race/ethnicity and adjustment for both sociodemographic and clinical factors.¹

The prevalence of diabetes among the overall study cohort was 1.4% (n=4685), 88.9% of the cohort were 20-39 years of age, and the majority of the cohort had a BMI considered in the normal range. When examining race/ethnicity, 31.9% of the cohort was Hispanic, 29.7% were non-Hispanic White, 21.5% were non-Hispanic Black, 7.4% were East/Central Asian, 3.5% were South/Southeast Asian, and 6.1% were classified as Unknown/Other.¹

Upon analysis, investigaors found the cumulative incidence for diabetes was 11.8% of those with gestational diabetes and 0.6% among women without gestational diabetes. Results indicated the adjusted hazard ratio (aHR) of gestational diabetes on diabetes risk postpartum was 11.5 (95% Confidence interval [CI], 10.8-12.2). Further analysis revealed differences according to race/ethnicity, with slight differences in risk observed among non-Hispanic Black (aHR, 10.3; 95% CI, 9.2-11.5), Hispanic (aHR, 12.2; 95% CI, 10.9-13.5), and non-Hispanic White (aHR, 12.5; 95% CI, 10.0-15.6) women.¹

Investigators also pointed out results suggesting gestational diabetes was associated with a lower likelihood of achieving glycemic control (aHR, 0.85; 95% CI, 0.79-0.92), with this impact most apparent among non-Hispanic Black (aHR 0.77; 95% CI, 0.68-0.88) and Hispanic (aHR, 0.84; 95% CI, 0.74-0.95) women. Investigators called attention to results indicating adjustment for screening bias and loss to follow-up attenuated racial/ethnic differences in risk of developing diabetes but had minimal effect on glycemic control.¹

“Our findings highlight the importance of regular diabetes screening following a gestational diabetes, particularly in the first 12 months following delivery—which was marked by the highest incidence of diabetes and least likelihood of glycemic control—in order to facilitate early detection and appropriate diabetes management,” said study investigator Katharine McCarthy, PhD, MPH, assistant professor of Population Health Science and Policy, and Obstetrics, Gynecology and Reproductive Science and a member of the Blavatnik Family Women’s Health Research Institute at Icahn Mount Sinai.² “In addition to care coordination between obstetric and primary care providers, provider education on the importance of obstetric history-taking is essential in facilitating diabetes awareness and early glycemic control.”

References:

1. McCarthy KJ, Liu SH, Huynh M, et al. Influence of Gestational Diabetes Mellitus on Diabetes Risk and Glycemic Control in a Retrospective Population-Based Cohort. Diabetes Care 2023; dc221676. https://doi.org/10.2337/dc22-1676
2. Icahn Mount Sinai. People who develop diabetes after pregnancy are less likely to regain control of blood sugar if they had gestational diabetes. EurekAlert! June 21, 2023. Accessed June 21, 2023. https://www.eurekalert.org/news-releases/993172.
3. Chamany S, Silver LD, Bassett MT, et al. Tracking diabetes: New York City's A1C Registry. Milbank Q. 2009;87(3):547-570. doi:10.1111/j.1468-0009.2009.00568.x