Obstetrical outcomes
The data for obstetrical outcomes were obtained from the M0 data and
included the following: gestational age at the time of delivery, the
presence or absence of placental abruption, mode of delivery, umbilical
artery (UmA) pH, and maternal transfusion. The mode of delivery was
categorized into vaginal delivery or cesarean section (CS). In the
present study, placental abruption was diagnosed clinically based on the
clinical findings of abdominal pain, vaginal bleeding, uterine
contractions, fetal distress, and vital signs’ abnormalities at the
discretion of the obstetrician in charge. Histological confirmation was
not mandatory for the diagnosis of placental abruption during the
present analysis. Fetal arterial blood was obtained from the site of
delivery, and UmA pH was measured immediately after delivery. Fetal
acidosis was stratified by UmA pH <7.20, <7.10, or
<7.00 based on a previous study, which reported that the UmA
pH threshold of 7.20 was associated with an increased risk of adverse
short-term outcomes,14 UmA pH threshold of 7.10 was
associated with an increased risk of adverse neurological
sequelae,15 and cerebral palsy was more frequent at
UmA pH <7.00.16