Overt diabetes imposes a comparable burden on outcomes as pregestational diabetes: a cohort study

BACKGROUND: Women with diabetes first diagnosed during pregnancy (overt diabetes) may be at the same risk level of adverse outcomes as those with known pregestational diabetes. We compared pregnancy outcomes between these groups. METHODS: We evaluated pregnant women with type 2 diabetes, pregestational or overt diabetes, attending high risk antenatal care in two public hospitals in Southern Brazil, from May 20, 2005 to June 30, 2021. Outcomes were retrieved from electronic medical records. Risk of adverse outcomes, expressed as relative risk (RR) and 95% confidence interval (CI), were calculated using Poisson regression with robust estimates. RESULTS: Of 618 women, 33% were labelled as having overt diabetes and 67%, pregestational diabetes. Baseline maternal characteristics were similar: there was a slight, non-clinically relevant, difference in maternal age (33 ± 5.7 years in women with pregestational diabetes vs. 32 ± 6.0 years in women with overt diabetes, p = 0.004); and women with overt diabetes reported smoking almost twice compared to those with pregestational diabetes (12.3% vs. 6.5%, p = 0.024). There were no relevant differences between the groups regarding pregnancy outcomes, although there was a trend of higher neonatal intensive care admission in the group of women with pregestational diabetes (45.2% vs. 36.1%, p = 0.051). CONCLUSIONS: Overt diabetes was diagnosed in one third of this cohort of pregnant women with hyperglycemia. Their pregnancy outcomes were similar to those of women with pregestational diabetes and were mostly related to maternal demographic characteristics and metabolic control. A call to action should be made to identify women of childbearing age at risk for pre-pregnancy diabetes; to detect hyperglycemia before conception; and to implement timely preconception care to all women with diabetes. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13098-022-00939-1.