Comparison of pancuronium and vecuronium for fetal neuromuscular blockade during invasive procedures.

Neuromuscular blocking agents, used to arrest fetal motion for invasive intrauterine procedures, may cause temporary fetal heart rate changes. After 21 invasive procedures using either pancuronium bromide or vecuronium bromide, post-procedure fetal heart rate tracings were retrospectively compared. Pancuronium was associated with an increased fetal heart rate and decreased beat-to-beat variability for 2.5 hours after its use, whereas vecuronium caused no fetal heart rate changes. Vecuronium bromide offers advantages over pancuronium, because the decreased effect on the fetal heart allows better assessment of fetal well-being immediately following invasive intrauterine procedures.