MATERNAL CARDIOVASCULAR HAEMODYNAMICS IN NORMAL AND COMPLICATED PREGNANCIES

Why should obstetricians study maternal cardiac function in normal and complicated pregnancies? Despite our understanding of the importance of disease processes, such as autoimmunity, impaired renal function and long-standing diabetes, on the placenta and thus pregnancy outcome, new data is emerging to suggest that early central cardiovascular adaptions are central to pregnancy success. Furthermore, successful maternal cardiovascular adaptions are a diagnostic test of longer-term cardiovascular health for the mother. The importance of the maternal ‘cardiac pump’ as the “core” of adaptation to pregnancy has increased in the last years. Studies identifying high risk patients by uterine artery Doppler waveforms in the 2nd trimester indicate that high uterine vascular impedance affects a proportion of women (resulting in severe preeclampsia) while the majority remain well. This dichotomy in maternal response is one explanation for the poor screening characteristics of uterine artery Doppler in unselected women. Women destined to develop preeclampsia with abnormal uterine artery Doppler have a latent period before the disease develops. During this phase, the heart adapts to alterations in circulating blood volume, placental implantation, and maternal peripheral vascular impedance. We believe that disordered heart function is an unavoidable part of the disease spectrum of preeclampsia, since it makes many adaptions even in the face of normal pregnancy. In this article we summarise the experience of our group and the published literature concerning maternal cardiac performance in normal and complicated pregnancies. These findings are relevant to modern day clinical practice.