“…PPHN was then defined as severe hypoxemia (PaO 2 < 37.5–45 mm Hg in an FiO 2 of 1.0) requiring mechanical ventilation and inhaled nitric oxide treatment (selective pulmonary vasodilator) . Diagnosis of PPHN was only reached if right‐to‐left shunting in the ductus arteriosus was observed by echocardiography, in the absence of a structural heart defect or severe lung hypoplasia . In addition, the following perinatal data were collected: maternal preeclampsia, maternal selective serotonin reuptake inhibitor use during pregnancy, IUTs, ultrasound data prior to IUT, preterm premature rupture of membranes, place of birth, gestational age at birth, birth weight, sex, mode of delivery, Apgar score at 5 minutes, (umbilical cord) blood gas analysis within 1 hour postnatally (pH, base excess, lactate), meconium aspiration syndrome, early‐onset sepsis, perinatal asphyxia, severe brain damage, and mortality within 1 month after birth.…”