The effect of neuromuscular blockade on human fetal heart rate and its variation.
OBJECTIVE
To determine the effect of neuromuscular blockade on fetal heart rate and its variation.


METHODS
Case control study.


METHODS
Tertiary referral fetal medicine unit in a London teaching hospital.


METHODS
Forty women with rhesus iso-immunisation requiring an intravascular fetal blood transfusion between 28 and 34 weeks gestation.


METHODS
Intravascular injection of pancuronium to the fetus prior to fetal blood transfusion in 20 cases.


METHODS
Comparison between the group receiving pancuronium and the control group with regard to differences in perceived fetal activity and computer derived numerical indices of fetal heart rate and fetal heart rate variation after fetal blood transfusion.


RESULTS
After transfusion in the control group, there were fewer perceived fetal movements, a small reduction in fetal heart rate but no differences in number of fetal heart rate accelerations or measures of fetal heart rate variation. In the study group, pancuronium produced no change in fetal heart rate despite a virtual abolition of perceived fetal movements and fetal heart rate accelerations. Measures of fetal heart rate variation were reduced by 60%. Comparison of the pre- to post-transfusion changes between the two groups showed significant differences for all fetal heart rate indices.


CONCLUSIONS
Fetal activity accounts for more than half the measured variation of the human fetal heart rate.
Spencer
J A
JA
Department of Obstetrics and Gynaecology, University College London Medical School, UK.
Ryan
G
G
Ronderos-Dumit
D
D
Nicolini
U
U
Rodeck
C H
CH
D001805:Blood Transfusion, Intrauterine; D016022:Case-Control Studies; D005260:Female; D005324:Fetal Movement; D006340:Heart Rate, Fetal / Q000187:drug effects*; D006801:Humans; D007275:Injections, Intravenous; D010197:Pancuronium / Q000494:pharmacology*; D011247:Pregnancy; D012203:Rh Isoimmunization / Q000628:therapy
D010197:Pancuronium