Maternal cardiac function in women at high risk for pre-eclampsia treated with 150mg aspirin or placebo: an observational study.

Abstract

To compare maternal haemodynamics in women at low and high risk for preterm pre-eclampsia (PE), and between those at high risk who are randomised to aspirin or placebo. Prospective, longitudinal observational study. Maternity units in six UK hospitals. Women participating in the Aspirin for Prevention of Preterm Pre-eclampsia (ASPRE) trial. The population comprised three groups of women: low risk for preterm PE (n=1362), high risk for preterm PE treated with aspirin (n=208) and high risk for preterm PE on placebo (n=220). Women had four visits during pregnancy: 11-14, 19-24, 30-34, and 35-37weeks' gestation. Blood pressure was measured with a device validated for pregnancy, and PE and maternal haemodynamics were assessed with a bioreactance monitor at each visit. A multilevel linear mixed-effects analysis was performed to examine longitudinal changes of maternal haemodynamic variables, controlling for demographic characteristics, past medical history and medication use. Longitudinal changes of cardiac output (CO), mean arterial pressure (MAP), and peripheral vascular resistance (PVR). The low-risk group demonstrated the expected changes with an increase in CO and reduction in MAP and PVR, with a quadratic change across gestation. In contrast, the high-risk groups had a declining CO, and higher MAP and PVR during pregnancy. The administration of aspirin did not appear to affect maternal haemodynamics. Women screened as high risk for preterm PE have a pathological cardiac adaptation to pregnancy and the prophylactic use of aspirin (150mg oral daily from the first trimester) in this group may not alter this haemodynamic profile. In women at high risk of pre-eclampsia, prophylactic use of aspirin may not alter the impaired maternal cardiac adaptation.