Maternal smoking ıs associated with altered fetal left ventricular myocardial performance and fetoplacental hemodynamics

Maternal smoking is a well-established risk factor for adverse perinatal outcomes during pregnancy. However, its association with fetal left ventricular myocardial performance and fetoplacental hemodynamics remains incompletely understood. This study aimed to evaluate the association between maternal smoking and fetal left ventricular myocardial performance, myocardial time intervals, and cerebroplacental ratio (CPR) during the third trimester of pregnancy. This prospective study included 200 singleton pregnancies evaluated during the third trimester, comprising 100 women who actively smoked and 100 non-smoking controls. Fetal left ventricular myocardial performance was assessed using the myocardial performance index (MPI), including its individual myocardial time intervals: isovolumetric contraction time (ICT), isovolumetric relaxation time (IRT), and ejection time (ET). Fetoplacental circulation was evaluated using the cerebroplacental ratio (CPR) and Doppler ultrasonography. Multivariable linear regression models adjusted for maternal age, body mass index, gestational age at examination, parity, and estimated fetal weight percentile were used to identify independent associations between maternal smoking and fetal cardiovascular parameters. Fetuses of smoking mothers exhibited significantly higher left ventricular MPI values (0.492 ± 0.040 vs. 0.429 ± 0.027, p < 0.001), prolonged ICT and IRT values (both p < 0.001), and significantly lower CPR values (1.630 [1.448–1.923] vs. 1.995 [1.748–2.220], p < 0.001) compared with those of non-smoking mothers. Umbilical artery pulsatility index values were significantly higher and middle cerebral artery pulsatility index values were significantly lower in the smoking group (both p < 0.001). Maternal smoking remained independently associated with increased left ventricular MPI (B = 0.062, p < 0.001), prolonged ICT (B = 4.661 ms, p < 0.001), prolonged IRT (B = 5.623 ms, p < 0.001), and decreased CPR values (B = − 0.311, p < 0.001) after multivariable adjustment. No independent association was observed between maternal smoking and ET. Maternal smoking during the third trimester was independently associated with alterations in fetal left ventricular myocardial performance and fetoplacental hemodynamics. These alterations were characterized by prolonged isovolumetric myocardial time intervals, increased MPI values, and reduced CPR values, independent of estimated fetal weight percentile. Further studies incorporating neonatal outcomes and longitudinal follow-up are warranted to determine the clinical significance of these findings and their implications for fetal cardiovascular adaptation to maternal smoking exposure.