At mid-gestation, markers of placental function rather than maternal cardiac function are stronger determinants of birthweight.

Background: The role of maternal cardiac and hemodynamic assessment during normal and complicated pregnancies has gained attention during the last few years. Some researchers suggested that the manifestation of complications in pregnancy suffering from impaired placentation is mainly driven by preexisting cardiac changes, identifiable at an early stage by echocardiographic and hemodynamic assessment. It is therefore of great importance to determine the link between placental perfusion and maternal cardiac function and hemodynamics. Also, the impact of maternal cardiac function on birth weight has not been thoroughly studied.

Objective: To elucidate the possible association of maternal cardiovascular indices with placental perfusion at mid-gestation and birthweight.

Study design: Prospective study on women with singleton pregnancies attending Kings' College Hospital, London, UK for a routine hospital visit at 19 to 24 weeks of gestation. We recorded maternal characteristics and medical history, measured mean arterial pressure, heart rate, uterine artery pulsatility index, umbilical artery pulsatility index, middle cerebral artery pulsatility index, and serum placental growth factor. We also performed maternal echocardiogram to assess cardiac output and peripheral vascular resistance as well as indices of diastolic and systolic cardiac function. Multivariable regression modeling was used.

Results: Our cohort included 4006 women. Higher uterine artery pulsatility index values were associated with lower mean arterial pressure, heart rate, and left ventricular systolic function, after adjustment for maternal characteristics and subsequent development of hypertensive disorders of pregnancy and gestational diabetes mellitus. In a multivariable approach that explained 17.9% of the variance of the birthweight, we found that some cardiovascular indices provided small but significant contribution to the model after accounting for maternal factors and development of hypertensive disorders of pregnancy and gestational diabetes mellitus, uterine artery pulsatility index, and placental growth factor.

Conclusion: The findings of our study indicate a weak but significant association between maternal cardiovascular indices with placental perfusion at mid-gestation and birthweight. Our data would not support routine maternal cardiovascular assessment for predicting birthweight.