Randomized controlled trial of prepregnancy lifestyle intervention to reduce recurrence of gestational diabetes mellitus

BACKGROUND: Preconception lifestyle intervention holds potential for reducing gestational diabetes mellitus, but clinical trial data are lacking.OBJECTIVE: This study aimed to determine the effects of a prepreg-nancy weight loss intervention on gestational diabetes mellitus recurrence in women with overweight/obesity and previous gestational diabetes mellitus.STUDY DESIGN: A 2-site, randomized controlled trial comparing a prepregnancy lifestyle intervention with educational control was con-ducted between December 2017 and February 2022. A total of 199 English-and Spanish-speaking adults with overweight/obesity and pre-vious gestational diabetes mellitus were randomized to a 16-week pre-pregnancy lifestyle intervention with ongoing treatment until conception or educational control. The primary outcome was gestational diabetes mel-litus recurrence. Analyses excluded 6 participants who conceived but did not have gestational diabetes mellitus ascertained by standard methods.RESULTS: In the 63 (33%) women who conceived and had gestational diabetes mellitus ascertained (Ns=38/102 [37%] intervention vs 25/91 [28.0%] control; P=.17), those in the intervention group had significantly greater weight loss at 16 weeks compared with controls (4.8 [3.4-6.0] vs 0.7 [-0.9 to 2.3] kg; P=.001) and a greater proportion lost >5% of body weight (50.0% [17/34] vs 13.6% [3/22]; P=.005). There was no signif-icant difference in the incidence of gestational diabetes mellitus recur-rence between the intervention (57.9% [ns=23/38]) and the control group (44.0% [ns=11/25]; odds ratio, 1.8 [0.59-5.8]). Independent of group, greater prepregnancy weight loss predicted 21% lower odds of gestational diabetes mellitus recurrence (odds ratio, 0.79 [0.66-0.94]; P=.008). A = 5% weight loss before conception reduced the odds of gestational diabetes mellitus recurrence by 82% (odds ratio, 0.18 [0.04-0.88]; P=.03).CONCLUSION: Lifestyle intervention produced considerable pre-pregnancy weight loss but did not affect gestational diabetes mellitus rates. Given that the conception rate was 50% lower than expected, this study was underpowered.

Automated summary

This study aimed to determine the effects of weight loss intervention on gestational diabetes mellitus recurrence. The study found that lifestyle intervention resulted in significant weight loss, but did not significantly affect the incidence of gestational diabetes mellitus.