Pregnancy and postpartum cardiometabolic outcomes among women with overt diabetes compared to women with normoglycaemia, gestational diabetes and pre‐existing diabetes: A systematic review and meta‐analysis

Abstract Background and Aim Overt diabetes in pregnancy (ODiP) is a condition identified by the International Association of Diabetes and Pregnancy Study Groups (IADPSG) in 2010. Despite the clinical significance, our knowledge regarding its impact during pregnancy and the postpartum period is limited due to small sample sizes in previous studies. This systematic review and meta‐analysis (SRM) aimed to consolidate evidence on outcomes in the pregnancy and postpartum period among women with ODiP in comparison to women with gestational diabetes mellitus (GDM), pre‐existing diabetes (PED) and normoglycaemia. Material and Methods A comprehensive search was conducted across PubMed, Embase and Scopus for relevant studies published from January 1, 2010, to May 31, 2024. Eleven studies, including data from 16 135 pregnancies, were analysed. Results Women with ODiP had a significantly higher risk of gestational hypertension (RR 1.93; 95% CI 1.45, 2.58), pre‐eclampsia (RR 1.65; 95% CI 1.26, 2.16) and caesarean delivery (RR 1.14; 95% CI 1.01, 1.29) compared with GDM. Adverse neonatal outcomes such as large for gestational age (RR 1.45; 95% CI 1.13, 1.85), macrosomia (RR 1.66; 95% CI 1.05, 2.64), neonatal hypoglycaemia (RR 1.52; 95% CI 1.06, 2.19) and stillbirth (RR 4.30; 95% CI 1.69, 10.98) were also significantly higher than GDM. The risk of postpartum diabetes was 6 times higher than in women with GDM and 25 times higher than in women with normoglycaemia. Variations in diagnostic criteria and postpartum follow‐up duration contributed to heterogeneity. Conclusion This SRM demonstrates that ODiP is associated with significantly worse pregnancy and postpartum outcomes compared with GDM and normoglycaemia in pregnancy. These findings underscore the need for targeted clinical strategies to manage ODiP and mitigate adverse maternal and neonatal outcomes.