Effect of labor analgesia with nalbuphine hydrochloride on fetal response to vibroacoustic stimulation.

Objective: To evaluate the effect of labor analgesia with nalbuphine hydrochloride on the fetal response to vibroacoustic stimulation.

Study Design: The response to fetal acoustic stimulation (FAS) was recorded in 27 laboring patients before analgesia. After analgesia with 5 mg nalbuphine hydrochloride administered subcutaneously, the response to FAS was again recorded.

Results: No ominous fetal heart rate (FHR) patterns were observed. FAS reliably increased FHR baseline and long-term FHR variability and produced FHR accelerations. Nalbuphine hydrochloride analgesia did not produce a significant decrease in long-term FHR variability or alter FHR baseline but did reduce the number of FHR accelerations recorded.

Conclusion: FAS-induced FHR accelerations did not differ from those observed before analgesia. Analgesia with low doses of nalbuphine did not alter fetal response to FAS, which therefore offers a means of assessing fetal well-being even in the narcotized fetus.