ORCID

0009-0008-3130-5233 (Hayasaka), 0000-0003-2438-1699 (Kawakita)

Document Type

Article

Publication Date

2025

DOI

10.1002/pmf2.70096

Publication Title

Pregnancy

Volume

1

Issue

5

Pages

e70096

Conference Name

45th Annual Meeting- the pregnancy meeting of the Society for Maternal-Fetal Medicine, Jan. 27-Feb. 1, Denver, Colorado

Abstract

Objective

Although some studies show that exercise decreases the incidence of gestational diabetes mellitus (GDM), the optimal exercise intensity during pregnancy remains unclear. We examined GDM risk according to exercise intensity in pregnant individuals.

Methods

We analyzed data from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers‐to‐Be (nuMoM2b), a prospective study enrolling nulliparous individuals in the first trimester. Participants with pregestational diabetes or delivery before 20 weeks were excluded. Exercise intensity during the first (6–13 weeks’ gestation) and early second (16–21 weeks’ gestation) trimesters was categorized by metabolic equivalent of task hours per week (MET‐hr/week) as none, low intensity (< 7.5), moderate intensity (7.5–14.9), or high intensity (≥ 15). The primary outcome was GDM; secondary outcomes included preeclampsia, gestational hypertension, preterm birth, small‐for‐gestational‐age birth, and stillbirth. Adjusted relative risks (aRRs) with 95% confidence intervals (CIs) were calculated using a generalized linear mixed‐effects model with a Poisson distribution and robust error variance, controlling for the random effects of individuals and potential confounders.

Results

In the first trimester ( n = 9049), 30.2% of participants reported no exercise, 23.9% engaged in low‐intensity exercise, 19.0% in moderate‐intensity exercise, and 26.7% in high‐intensity exercise. In the early second trimester, 29.7% reported no exercise, 26.5% had low‐intensity exercise, 20.5% moderate‐intensity exercise, and 23.3% high‐intensity exercise. Compared with no exercise, high‐ and moderate‐intensity exercises were associated with a lower risk of GDM (aRR 0.63 [95% CI 0.51–0.78] and aRR 0.81 [0.68–0.96]), while low‐intensity exercise showed no significant association with GDM risk reduction. Moderate‐intensity exercise was also associated with a lower risk of preeclampsia. Notably, no exercise intensity was associated with an increased risk of any adverse pregnancy outcome.

Conclusion

High‐ and moderate‐intensity exercises during early pregnancy were associated with a lower risk of GDM compared to no exercise. These findings support the need for interventional trials to evaluate whether increasing exercise intensity during pregnancy can effectively prevent GDM.

Rights

© 2025 The Authors.

This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Data Availability

Article states: "The data that support the findings of this study are available from the corresponding author upon reasonable request."

Original Publication Citation

Tanamoto, T., Hayasaka, M., & Kawakita, T. (2025). Association between the intensity of exercise in the first trimester and early second trimester and the risk of gestational diabetes. Pregnancy, 1(5), Article e70096. https://doi.org/10.1002/pmf2.70096

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