Maternal and neonatal complications in pregnancies with and without pre-gestational diabetes mellitus

Objectives: To compare pregnancy complications in pregnancies with and without pre-gestational diabetes mellitus (DM) managed in a multidisciplinary high-risk diabetes antenatal clinic.Methods: This screening cohort study was undertaken at a large maternity unit in the United Kingdom between January 2010 and December 2022. We included singleton pregnancies that booked at our unit at 11-13 weeks' gestation. Univariate and multivariate logistic regression analysis was carried out to determine risks of complications in pregnancies with type 1 and type 2 DM after adjusting for maternal and pregnancy characteristics. Effect sizes were expressed as absolute risks (AR) and odds ratio (OR) (95 % confidence intervals [CI]).Results: The study population included 53,649 singleton pregnancies, including 509 (1.0 %) with pre-existing DM and 49,122 (99.0 %) without diabetes. Multivariate logistic regression analysis demonstrated that there was a significant contribution from pre-existing DM in prediction of adverse outcomes, including antenatal complications such as fetal defects, stillbirth, preterm delivery, polyhydramnios, preeclampsia and delivery of large for gestational age (LGA) neonates; intrapartum complications such as caesarean delivery (CS) and post-partum haemorrhage; and neonatal complications including admission to neonatal intensive care unit, hypoglycaemia, jaundice and hypoxic ischaemic encephalopathy (HIE). In particular, there was a 5-fold increased risk of stillbirth and HIE.Conclusions: The maternal and neonatal complications in pregnancies with pre-existing DM are significantly increased compared to those without DM despite a decade of intensive multidisciplinary antenatal care. Further research is required to investigate strategies and interventions to prevent morbidity and mortality in pregnancies with pre-gestational DM.