Intravenous pancuronium bromide for fetal neuromuscular blockade during intrauterine transfusion for red-cell alloimmunization.

Intravenous pancuronium bromide was administered into the umbilical cord by funipuncture to effect temporary fetal paralysis. Neuromuscular blockade was achieved in 12 fetuses undergoing a total of 34 intrauterine procedures for the treatment of severe red-cell alloimmunization. The same initial dose of 0.2 mg/kg fetal weight estimated by ultrasound was used in all cases, but anemic fetuses did not resume movement for prolonged periods. A relationship among fetal hematocrit, adjusted dose, and duration of paralysis was described by the equation: Duration (hours) = 5.24 + 10.30 adjusted dose (mg/kg) - 0.16 hematocrit (%) (R2 = 0.49; P less than .001). Intravenous pancuronium was found to be a safe and effective method for cessation of fetal movement during intrauterine procedures.