NPPB and Right ventricular hypertrophy: This may be due to the myocardial stress and right ventricular hypertrophy caused by PAH, along with the increased pulmonary vascular resistance in the mother, resulting in excessive stretching of myocardial cells that produce a large amount of BNP; consequently the failure of maternal cardiac function leads to fetal blood supply problems, leading to adverse outcomes for the fetus and newborn [26].