OP 29 The interaction between the maternal systemic and uteroplacental circulations in pregnancies resulting in small for gestational age newborns

Abstract

Introduction Pregnancies resulting in small for gestational age (SGA) newborns are associated with altered Uteroplacental and maternal systemic circulations. However, data on the interaction between these cardiovascular changes are scarce. Whether these pregnancies result from placental insufficiency only, or combined with impaired maternal cardiovascular adaptation, is yet to be established. Objective The aim of this study was to ascertain the interaction between the maternal systemic and uteroplacental circulations in pregnancies resulting in SGA neonates. Methods This was a prospective case-control study including pregnancies resulting in SGA neonates ( n = 142) and a group of pregnancies resulting in appropriate for gestational age (AGA) neonates ( n = 473), recruited after 20 weeks gestation. Maternal cardiac output (CO), stroke volume (SV) and systemic vascular resistance (SVR) were recorded using the USCOM®, while the aortic augmentation index (AIx), heart rate and pulse wave velocity (PWV) were recorded using the Arteriograph®. The uterine artery (UtA) mean pulsatility index (PI) was assessed at the same visit. The Mann–Whitney test was used to compare the two groups and logistic regression analysis was used to investigate and adjust for potential confounding variables. Results Compared to controls, the SGA pregnancies had significantly lower CO (median 6.02 L/min, IQR 5.22–6.98 vs 6.64 L/min, IQR 5.68–7.73, p p = 0.035), but significantly higher SVR (median 1263 dynes-sec/cm 5 , IQR 1030–1538 vs 1094 dynes-sec/cm 5 , IQR 935.4–1337, p p p p = 0.005 (0.63–0.87) and 6.40 (3.31–12.39); p Conclusion Placental insufficiency and impaired maternal cardiovascular adaptation are independently associated with the risk of delivery of an SGA neonate.