234. Maternal cardiovascular function at 35–37 weeks’ gestation: Normal vs hypertensive disorders of pregnancy

Abstract

Objective To examine the effects of maternal characteristics and obstetric and medical history on maternal cardiovascular parameters (MCPs) at 35–37 weeks’ gestation using bioreactance (NICOM). To investigate the potential value of combining maternal factors with multiples of the normal median values of MCPs at 35–37 weeks’ gestation in the prediction of pre-eclampsia (PE) and gestational hypertension (GH). Methods In 3013 singleton pregnancies maternal characteristics and medical history were recorded;uterine artery pulsatility index (UtA”PI), mean arterial pressure (MAP) and MCPs were measured. In those who remained normotensive, multivariable regression analysis was used to determine significant predictors of the MCPs among gestational age (GA), maternal characteristics and medical history. Multivariable logistic regression analysis was then used to determine if the maternal factors and MCPs made a significant contribution to predicting PE and GH. The performance of screening was determined by the area under ROC curves. Results Multivariable regression analysis demonstrated that significant independent prediction of MCPs including cardiac output, cardiac index, total peripheral resistance, stroke volume, MAP and heart rate, significant prediction was provided by GA, maternal characteristics and medical history. In pregnancies that subsequently delivered with PE or GH, total peripheral resistance and MAP were higher and maternal cardiac output was lower. The increases in total peripheral resistance and MAP were inversely related to gestational age at delivery. The performance of screening for PE and GH achieved by maternal characteristics and medical history was improved by the inclusion of MAP, but not by UtA”PI or MCPs. Conclusion MCPs are affected by maternal characteristics and medical and obstetric history, and they should therefore be converted into multiples of the normal median adjusted for significant independent predictors before their inclusion in combined screening for PE. In women developing term PE total peripheral resistance and MAP are increased and maternal cardiac output is reduced. However, assessment of MCPs at 35–37 weeks’ gestation is unlikely to improve the performance of screening for PE provided by maternal factors and MAP alone.