Predictors of neonatal resuscitation, low Apgar scores, and umbilical artery pH among growth-restricted neonates

Abstract

Objective: To identify risk factors associated with poorer immediate neonatal outcomes among growth-restricted neonates.

Methods: Records of all 530 growth-restricted neonates born between January 1989 and February 1995 were reviewed. Outcomes included resuscitation measures, Apgar scores, and umbilical blood gas values. Neonates were assigned to one of six anesthetic groups, and outcomes were compared. Predictors of poorer outcomes were examined using logistic and linear regression.

Results: Neonates exposed to general anesthesia were more likely to be intubated (37.9% versus 4.1%, P < .001, Pearson chi2) and had lower mean 1- (4.0 versus 7.0) and 5-minute (6.5 versus 8.4) Apgar scores (P < .01, Scheffé) than those in all other anesthetic groups. They also had significantly lower umbilical artery (UA) pH values than neonates who received nalbuphine, epidural, or no anesthesia (7.21 versus 7.28, 7.26, 7.29, respectively; P < .01, Scheffé). Factors that significantly and independently predicted intubation among all neonates included exposure to general anesthesia (odds ratio [OR] 4.1; 95% confidence interval [CI] 1.9, 8.9) and lower infant weight (OR 10.1 per kg decrease; CI 5.1, 20). Factors predicting UA pH at most 7.15 included preeclampsia (OR 3.0; CI 1.5, 5.9) and older maternal age (OR 1.3 per 5 years; CI 1.02, 1.64); vertex delivery (OR 0.5; CI 0.2, 0.9) was protective. Factors predicting a 5-minute Apgar less than 7 were meconium (OR 1.5 per category going from none to terminal to light to heavy; CI 1.04, 2.3), general anesthesia (OR 6.9; CI 2.6, 18.2), lower infant weight (OR 16.5 per kg decrease; CI 7.8, 34.5), and vaginal breech delivery (OR 7.0; CI 1.8, 28.6); cesarean delivery (OR 0.2; CI 0.08, 0.66) was protective. Spontaneous vertex delivery raised the UA pH, and preeclampsia, amnioinfusion, breech delivery, and general anesthesia significantly and independently lowered the UA pH among all neonates. For infants delivered by cesarean, "fetal distress," preeclampsia, previous spontaneous abortion, failed forceps use, and nalbuphine significantly and independently predicted lower UA pH.

Conclusion: Risk factors for poorer immediate neonatal outcomes among growth-restricted neonates include preeclampsia, fetal distress, breech delivery, forceps use, nalbuphine during labor, lower infant weight, and general anesthesia.