Alterations in maternal cardiovascular parameters and their impact on uterine and fetal circulation in hypertensive pregnancies and fetal growth restriction

Objective

To examine potential alterations in maternal cardiovascular parameters in hypertensive pregnancies with or without fetal growth restriction (FGR) in comparison to uncomplicated normotensive pregnancies, and to determine the correlation between maternal cardiovascular parameters and changes in umbilical and uterine artery circulation.

Materials and methods

This study enrolled 73 pregnant women starting from the 20th week of gestation, categorized into three groups: hypertensive conditions (pregnancy-induced hypertension, preeclampsia or eclampsia, n = 30), hypertensive conditions with FGR (n = 8) and a control group of healthy normotensive pregnant women (n = 35). All participants underwent echocardiography to assess cardiac output and calculate peripheral vascular resistance. Additionally, fetal biometric measurements and Doppler ultrasound examinations of the uterine and umbilical artery were performed. The results were standardized into gestational age-adjusted z-scores.

Results

The mean pulsatility index (PI) of the uterine artery (1.36, p < 0.001) and umbilical artery PI z-scores (1.32, p < 0.001) showed significant increases in the hypertensive conditions + FGR group. Maternal cardiac output z-scores were notably lower in both the hypertensive + FGR group (−2.62, p = 0.001) and the hypertensive group (−2.49, p < 0.001). Peripheral vascular resistance was significantly elevated in the hypertensive + FGR group (7.43, p < 0.001) and the hypertensive group (6.06, p < 0.001). There was a positive correlation between maternal peripheral vascular resistance and uterine artery PI (R² = 0.172; p = 0.0004), and a negative correlation between cardiac output and uterine artery PI (R² = 0.067; p = 0.031). However, significant correlation between maternal cardiovascular parameters and umbilical artery PI was not identified.

Conclusions

Maternal cardiac output exhibits a significant decrease whereas peripheral vascular resistance increases in hypertensive pregnancies, irrespective of the presence of FGR. Both uterine and umbilical artery PI notably increase when hypertensive pregnancies are accompanied by FGR. A positive correlation exists between maternal peripheral vascular resistance and uterine artery PI, as well as a negative correlation between maternal cardiac output and uterine artery PI. However, changes in maternal cardiovascular parameters do not exhibit significant correlations with umbilical artery PI.