Effects of maternal pulmonary arterial hypertension on fetal hemodynamics and maternal‐fetal outcome in late pregnancy

Abstract Purpose The aim of this study was to investigate the effects of maternal pulmonary arterial hypertension (PAH) on fetal hemodynamics in the third trimester and to identify hemodynamic indicators associated with adverse maternal and fetal outcomes. Methods We recruited 48 pregnant women with PAH in the third trimester and 32 women with normal pregnancies as controls matched for age and gestational week. Fetal growth and hemodynamic parameters were assessed by two‐dimensional and color Doppler. All cases were followed up until delivery and maternal and fetal outcomes were collected. High throughput sequencing method was used to determine differential miRNA patterns in plasma exposed to pulmonary arterial hypertension (PAH) in pregnant women. We then performed the validated of key differentially expressed miRNAs by real‐time PCR. Results Compared with the normal and mild PAH groups, resistance index (RI), pulsatility index (PI) of the fetal umbilical artery (UA) and quantitative ductus venosus (QDV) blood flow were increased in subjects with moderate to severe PAH, while PI and the ratio of peak systolic velocity (PSV) to end‐diastolic velocity (EDV) (S/D) of the middle cerebral artery (MCA) were decreased. Compared with the normal group, subjects in the mild and moderate PAH groups had lower neonatal weight, shorter neonatal height, and higher preterm birth rates. In addition, miRNA sequencing data showed that PAH affected the levels of 23 miRNAs in plasma. At the same time, we showed that PAH significantly decreased the level of miR‐1255a and increased the level of miR‐548ar‐3p by real‐time PCR. Conclusion In the group of pregnant women with moderate to severe pulmonary hypertension, there was a higher proportion of preterm births and low birth weight babies. Hemodynamic changes in the fetal UA, MCA, and ductus venosus (DV) during late pregnancy were associated with adverse fetal outcomes. At the same time, miRNA sequencing results showed that miR‐1255a and miR‐548ar‐3p may play an important role in the development of PAH.