The influence of maternal epidural analgesia upon intrapartum fetal oxygenation

Abstract

Objective: The use of maternal epidural analgesia in labor may be associated with non-reassuring fetal heart rate (FHR) patterns. We aimed to assess changes in fetal oxygen saturation (FSpO(2)) during epidural analgesia in labor.

Methods: This was a prospective observational study. Twenty healthy parturients were enrolled following the inclusion criteria. Informed consent was obtained. Mode of delivery, use of oxytocin, maternal blood pressure, umbilical cord blood analysis, Apgar score, and neonatal outcomes were evaluated. Ropivacaine at a low concentration of 0.1% (1 mg/mL) co-administered with an opioid (fentanyl 2.5 microg/mL) was used. The values of fetal oxygen saturation were registered continuously 10 minutes before the administration of the analgesic drug and during the following 30 minutes after administration. Pulse oximetry was used simultaneously with cardiotocography (CTG).

Results: The average value for fetal oxygen saturation before the analgesic drug administration was 44.3 +/- 8.8%; during the first 10 minutes following administration it was 41.3 +/- 7.2% (p = 0.25) and during the following 20 minutes it was 43.05% +/- 6.9% (p = 0.63). There was no direct relationship between non-reassuring CTG pattern appearance and FSpO(2) <30% (RR = 1.11, 95% CI 0.76-1.64). No significant correlation was found between FSpO(2) values within the first 30 minutes of epidural analgesia and neonatal acidotic status (pH <or=7.00; RR = 0.33, 95% CI 0.04-3.09, and base excess <or=-12 mmol/L; RR = 1, 95% CI 0.21-4.71).

Conclusions: There were no differences in FSpO(2) values in the first 30 minutes following administration of analgesic drugs and most of the cases with non-reassuring CTG patterns had values of FSpO(2) constantly >or=30%.