Maternal vascular indices and hemodynamic parameters at 36 weeks' gestation in gestational and pre‐existing diabetes mellitus

Abstract Objective To compare maternal vascular indices and hemodynamic parameters at 35–37 weeks' gestation in pregnancies complicated by gestational diabetes mellitus (GDM), those with pre‐existing diabetes mellitus (DM) and those without GDM or pre‐existing DM. Methods This was a prospective observational study in women with a singleton pregnancy attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. The visit included recording of maternal demographic characteristics and medical history, and measurement of vascular indices and hemodynamic parameters using a non‐invasive operator‐independent device. These included carotid‐to‐femoral pulse‐wave velocity, augmentation index, cardiac output, stroke volume, central systolic and diastolic blood pressure, total peripheral resistance and heart rate. The values in the GDM and pre‐existing DM groups were compared to those in the unaffected group. Results We examined 6746 women, of whom 396 were excluded because they had chronic hypertension or developed pre‐eclampsia or gestational hypertension. The study population of 6350 pregnancies contained 99 (1.6%) with pre‐existing Type‐I or Type‐II DM and 617 (9.7%) that developed GDM, including 261 (42.3%) that were treated with diet alone, 239 (38.7%) treated with metformin alone and 117 (19.0%) treated with insulin with or without metformin. Among women with GDM and those with pre‐existing DM, compared to those without GDM or pre‐existing DM, there was a higher median cardiac output and heart rate, central systolic and diastolic blood pressure and pulse‐wave velocity, but there was no significant difference in stroke volume and total peripheral resistance. There were no significant differences within the GDM group according to treatment type, except for higher heart rate in women treated with metformin alone compared to the group treated with diet alone. Conclusion Women with GDM and those with pre‐existing DM have evidence of early vascular disease in the third trimester, and this may contribute to their increased long‐term cardiovascular risk. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.