OBJECTIVES: Women with gestational diabetes mellitus (GDM) have an elevated life-time risk of developing overt type 2 diabetes mellitus (T2DM). A systematic review and meta-analysis was undertaken to estimate risk of T2DM in women with GDM and assess the impact of ethnicity.

METHODS: Observational studies (2000-2022) on T2DM were identified from PubMed and Embase. Studies evaluating T2DM progression in women with GDM across different ethnicities, using a standard diagnostic GDM criterion and follow-up time of >6 weeks postpartum, were included. The primary endpoints included assessing pooled relative risk (RR) for incidence of T2DM among women with vs without GDM history and the absolute risk (risk difference) of developing T2DM across ethnicities. Additional risk factors contributing to T2DM development among women with GDM were identified. Random effects meta-analysis models were fitted using the DerSimonian and Laird method.

RESULTS: This analysis included 30 studies across ethnicities (Asian: n=9; white: n=16; mixed: n=4; Black: n=1). Mean age of women with GDM (n=52,097) who developed T2DM across ethnicities was <35 years. Women with GDM had a 6-fold higher pooled RR of developing T2DM vs healthy women (RR=5.722, 95%CI: 4.032; 8.120). Although pooled RR (95%CI) for T2DM was higher in White (8.808 [4.416;17.562]) vs Asian (4.033 [2.824;5.759]) and mixed ethnicities women (3.560 [1.891;6.702]), absolute risk (95%CI) of developing T2DM was higher in Asian (14.7% [0.12;0.283]) vs white women (11.4% [0.56;0.17]). Risk of developing T2DM was highest between 1-5 years of postpartum follow-up period (RR=9.056 [95%CI: 4.761;17.224]).

CONCLUSIONS: Women with GDM had a 6-fold higher likelihood of developing T2DM than healthy women, with the risk peaking within 1-5 years postpartum. Asian women with GDM are more likely to develop T2DM versus white women. As comprehensive ethnicity-specific studies are lacking, the notable impact of ethnicity on T2DM risk among predisposed women warrants further attention.