[Administration of pethidine in labor with meconium contaminated amniotic fluid: effect on fetal outcome and respiratory disorders].

OBJECTIVE: The aim of the study was to evaluate the effects of maternal pethidine administration on fetal outcome and incidence of neonatal respiratory distress in deliveries with meconium stained amniotic fluid (MAF).

STUDY DESIGN: Between 1989 and 1992, 849 live infants had MAF. For pain relief during labor 214 women received pethidine 50-150 mg i.m. The control group included 401 infants with MAF, who were not exposed to sedatives, analgesics, and anesthetics during labor. Fetal cord pH, Apgar 1 min (A1), Apgar 5 min (A5), and incidence of respiratory distress were compared retrospectively between the groups. Statistics and calculations were done by means of uni- and multivariate analyses.

RESULTS: The presence of thickened MAF increased significantly the risk of low A1, low A5, low arterial cord pH, and the incidence of respiratory distress (p = 0.003, = 0.0003, = 0.016, = 0.000). Infants with thickened MAF, low A1, and low fetal cord pH proved to have an exceedingly high risk of respiratory distress. The application of pethidine (0 mg, 50 mg, 100-150 mg) does not discriminate the variables as arterial cord pH, A1, A5, and the incidence of respiratory distress significantly. However the medium cord pH values of infants without pethidine (7.27, s = 0.075) and with 100-150 mg pethidine (7.25, s = 0.078) were significantly different (p = 0.0006). The incidence of arterial pH, 7.10 did not differ significantly in cases with different pethidine doses.

CONCLUSIONS: Thickened MAF is an obstetric hazard with small but significantly increased risks for poor fetal outcome and neonatal respiratory distress. This study failed to identify additional neonatal risks engendered by use of pethidine in cases of MAF.