BACKGROUND AND OBJECTIVE: In many deliveries, determination of umbilical artery PH is considered a suitable tool for predicting the risk of damage to the fetus and determining the likelihood of associated complications. This study was performed in order to investigate the relationship between maternal risk factors and umbilical artery PH in premature infants.

METHODS: In this case-control study, 600 premature neonates (gestational age of 27-37 weeks), were examined in terms of umbilical artery pH within the first 5 minutes after birth. In total, 181 newborns suffering from acidosis with pH> 1.7 (case group) and 419 neonates without acidosis (control group) were compared in terms of maternal history of placental detachment, maternal diabetes, prolonged rupture of membranes, oligohydramnios, chorioamnionitis, multiple birth pregnancy, placental previa, intrauterine growth retardation, and late deceleration of fetal heart rate.

FINDINGS: Fetal acidosis was reported in 7.2% of cases with intrauterine growth restriction  (N=30 ) (OR=3.1), 8.3% of neonates with placental detachment (N=15) (OR= 2.25), 7.2% of cases with chorioamnionitis (N=13) (OR=4.54) 14.9% of multiple births (N=27) (OR=1.79), 5.5% of cases with maternal anemia (N=10) (OR= 2.64), and 28.6% of newborns with late deceleration of fetal heart rate (N=44) (OR= 57%) (P= 0.001, 0.002, 0.03, 0.03, 0.04, and 0.03, respectively). However, fetal acidosis was not significantly associated with prolonged rupture of membranes, placental previa, oligohydramnios, preeclampsia, maternal diabetes, or diseases of the lung, liver, and kidney.

CONCLUSION: Intrauterine growth retardation, chorioamnionitis, placental detachment, multiple birth pregnancy, maternal anemia, and late deceleration of fetal heart rate increased the risk of fetal acidosis in premature births.