Background: To determine the effect of atracurium or pancuronium on onset and duration of fetal paralysis, movements and heart rate parameters directly after transfusion, using computer analyzed fetal heart rate recording (c-FHR).
Methods: Double blind randomized study of 23 RhD alloimmunized pregnant women requiring an intravascular intrauterine fetal blood transfusion (IUT) between 24 and 36 weeks. Atracurium was injected in 11 fetuses at 17 IUT's and pancuronium in 12 fetuses at 19 IUT's. For statistical analysis the Mann-Whitney test was used.
Results: No statistical differences were found in fetal heart rate and movements between both groups before transfusion. The fetal movements returned more rapidly in the atracurium group when compared to the pancuronium-group (median 24 vs. 57 min, range 6-55 vs. 4-220; (p<0.02). Fetal movements did not hamper the procedure in any case. The atracurium group showed significantly more fetal movements (p<0.01), more accelerations (0<0.05) but no significant reduction of fetal heart rate variability directly after transfusion which was in direct contrast to the pancuronium group.
Conclusions: Neuromuscular blockade with atracurium produces sufficient paralysis for intrauterine transfusion with minimal disturbance of the parameters used to monitor fetal wellbeing after the procedure. Although the routine use of fetal paralysis during IUT may be questionable, we believe that when it is necessary the use of atracurium is the better choice.