Maternal Cardiovascular Changes in Pregnancies Complicated by Gestational Diabetes Mellitus: A Longitudinal Cohort Study

Background Pregnancy is associated with significant cardiovascular change. Gestational Diabetes (GDM) is one of the most commonly encountered medical disorders in pregnancy and carries an increased risk of gestational hypertensive disorders, but the pattern of cardiovascular adaptation associated with it is poorly understood. The aim of this longitudinal study was to investigate longitudinal changes in maternal haemodynamics in pregnancies complicated by GDM.MethodsThis is a longitudinal observational study of maternal cardiac output (CO), heart rate (HR), stroke volume (SV), total peripheral resistance (TPR), mean arterial pressure (MAP), brachial (BrAIx) and aortic (AoAIx) augmentation index and pulse wave velocity (PWV), amongst women with GDM compared to healthy controls. Women with GDM were considered both as a combined group, and as separate subgroups by treatment modality.ResultsAmongst healthy pregnancies, and the participants with GDM, maternal HR increased with advancing gestation, SV decreased, and CO showed no significant change. TPR, BrAIx, AoAIX and PWV increased, and MAP did not significantly change, with advancing gestation.Third trimester BrAIx and AoAIx were increased, and CO was lower, among women with GDM compared to low-risk women. No causal relationships between maternal haemodynamics and the need for treatment requirement of GDM were identified. Compared to the healthy women, BrAIx and AoAIx were increased in all the GDM subgroups, but CO was decreased only among women treated with metformin, and not the women treated with diet or metformin with insulin.We also observed a trend towards an altered longitudinal pattern of BrAIx, AoAIx, CO, SV, and TPR amongst the women with GDM taking metformin, compared to the women treated with dietary management, which did not meet statistical significance.ConclusionsWomen with GDM demonstrate altered haemodynamics compared to women with healthy pregnancies. Our findings may explain the association between GDM and placental medicated disease, and a role for metformin in the prevention of these complications.