LAUSR

BACKGROUND Over the years, there has been an increasing interest in the assessment of maternal hemodynamic responses during pregnancy. With the use of both non-invasive devices and/or maternal echocardiography it has been shown that mothers who have pregnancy complications have altered hemodynamics compared to those who have uncomplicated pregnancies. It has also been suggested that pre-existing maternal cardiac changes might drive the development of complications in pregnancy which are associated with impaired placentation. To understand, however this potential link in complicated pregnancies, it is important to clarify whether placental function is associated with maternal cardiac functional indices in normal pregnancies. OBJECTIVE To determine whether placental function, perfusion and fetal weight are associated with maternal cardiac hemodynamic responses at 35-36 weeks gestation in normal pregnancies. STUDY DESIGN Prospective screening of women attending Kings' College Hospital for routine hospital visit at 35-37 weeks' gestation. We recorded maternal characteristics and measured mean arterial pressure, uterine artery pulsatility index, sonographic estimated fetal weight and serum placental growth factor and soluble fms-like tyrosine kinase 1 (sFLT-1). We also performed maternal echocardiogram to assess cardiac output and peripheral vascular resistance as well as indices of diastolic and systolic function, including global longitudinal systolic function and left ventricular mass indexed to body surface area. RESULTS We studied 1386 women. Maternal characteristics were associated with both maternal hemodynamics and functional and structural indices. Uterine artery pulsatility index was associated with left ventricular mass (p=0.03) and global longitudinal systolic function (p=0.017). There were significant non-linear associations between placental growth factor and cardiac output and peripheral vascular resistance (p<0.001 for both) and between sFLT-1 and peripheral vascular resistance (p=0.018). Estimated fetal weight was associated with maternal cardiac output (mean increase=0.186, 95% CI 0.133 to 0.238, p<0.001) and peripheral vascular resistance (mean decrease=-0.164, 95% CI -0.217 to -0.111, p<0.001). No association was noted between placental and fetal parameters and maternal cardiac functional and structural indices. In multivariable analysis, placental growth factor remained strongly associated with maternal cardiac output and peripheral vascular resistance (p=0.002 for both) over and above maternal characteristics and estimated fetal weight. Estimated fetal weight was associated with left ventricular mass (0.102, 95% CI 0.044 to 0.162, p=0.001). CONCLUSION The results of this study suggest a strong link between maternal hemodynamic responses and fetoplacental needs across the whole spectrum in normal pregnancies. These findings would also indicate that in order to diagnose maternal cardiac dysfunction in pregnancies complicated by impaired placentation a more extensive echocardiographic assessment might be needed rather than relying on hemodynamics which are strongly associated with feto-placental indices.