Investigators Identify Obesity at Age 20 as Predictor of Postpartum Impaired Glucose Tolerance, Diabetes

In a study of women aged 20, obesity was an independent predictor for the onset of postpartum impaired glucose tolerance, diabetes, and postpartum insulin resistance. In the study published in Diabetes Research and Clinical Practice, investigators aimed to determine the association between obesity at age 20 and weight gain from age 20 to pregnancy and postpartum impaired glucose tolerance for patients with a history of gestational diabetes (GDM).¹

“We found that obesity at age 20 was an independent predictor for the onset of postpartum IGT (impaired glucose tolerance) and DM (diabetes) in women with a history of GDM,” the study authors said.¹ “GDM is reported to result from IGT caused by pancreatic β-cell dysfunction in the context of chronic insulin resistance.”

GDM is a form of glucose intolerance that occurs during pregnancy and poses a short- and long-term risk to the mother and infant. It is common in pregnancy, with 7% of pregnancies in the US being complicated by diabetes of any kind, with 86% of those cases being GDM. Risk factors for GDM can include an increased body weight, decreased physical activity, a first-degree relative with diabetes, high-risk ethnicity—including African American, Latino, Native American, Asian American, and Pacific Islander—hypertension, and an abnormal oral glucose test. However, the rates of compliance with recommended postpartum screening are low at approximately 30%, according to a study published in the European Journal of Obstetrics and Gynecology and Reproductive Biology.^2,3

In the current study, investigators aimed to determine if obesity at age 20 and weight gain from age 20 were independent factors for the onset of postpartum impaired glucose tolerance and diabetes for Japanese women with a history of GDM. Patties included completed glycemic control during pregnancy between April 2021 and March 2025. Patients had a history of GDM and underwent a 75-g oral glucose tolerance test 12 weeks after giving birth. Patients also received nutritional education upon their first visit, and they were seen every 1 to 3 weeks. The primary end point included whether obesity at age 20 years and weight gain from age 20 years to pregnancy were independent risk factors, and secondary end points included obesity at all 3 time points being an independent risk factor as well as whether obesity at age 20 and weight gain from age 20 years to pregnancy were risk factors for postpartum insulin resistance.¹

Approximately 800 patients were registered for the study, but 467 underwent an oral glucose tolerance test at 6 to 12 weeks postdelivery. Further, 433 were included in the final population, according to the study authors. The mean age for GDM was 33.4 years, and the median gestational age at diagnosis was 15 weeks. Approximately 13.2% of patients had a history of GDM, and 50.8% had a family history of diabetes. Additionally, 45% of patients underwent educational hospitalization, and 64.7% were administered insulin therapy.¹

Investigators found that the time from the delivery date to the postpartum 75-g oral glucose tolerance test was 9 weeks. Postpartum impaired glucose tolerance and diabetes occurred in 34.2% of women and 1.8% of women, respectively. Compared with patients (64%) who had normal glucose tolerance, the impaired glucose tolerance and diabetes group (36%) had significantly higher body mass index (BMI) at age 20 years at 20.6 and 21.3 kg/m², respectively, and obesity at age 20 years at 4.7% and 12.2%, respectively. However, there were no significant differences for prepregnancy BMI and obesity or postpartum BMI and obesity. The study authors stated that “obesity at age 20 was an independent predictor for the onset of postpartum IGT and DM (aRR: 1.726, 95 % CI: 1.217–2.446).” However, they found that weight loss from delivery to the date of the postpartum 75-g OGTT was also an independent preventive factor for both outcomes.¹

“We identified weight loss from delivery to the date of the postpartum 75-g OGTT as an independent preventive factor for the onset of postpartum IGT and DM in women with a history of GDM,” the study authors said.¹ “Therefore, in women with a history of GDM, greater weight loss from delivery to the date of the postpartum 75-g OGTT may reduce the risk of IGT and DM.”

READ MORE: Diabetes Resource Center

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REFERENCES

1. Yamashita A, Kaku M, Matsunaga M, et al. Association between obesity at age 20 and postpartum glucose tolerance in women with a history of gestational diabetes mellitus. Diabetes Res Clin Pract. Published online October 3, 2025. doi:10.1016/j.diabres.2025.112930

2. Kunarathnam V, Vadakekut ES, Mahdy H. Gestational Diabetes. [Updated 2025 Sep 15]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK545196/

3. Zafrir-Danieli H, Houri O, Rotem R, et al. Gestational diabetes mellitus - Can we do better with postpartum diabetes screening?. Eur J Obstet Gynecol Reprod Biol. 2024;303:153-158. doi:10.1016/j.ejogrb.2024.10.006