Immediate and delayed effects of antenatal corticosteroids on fetal heart rate: a randomized trial that compares betamethasone acetate and phosphate, betamethasone phosphate, and dexamethasone.
OBJECTIVE
The purpose of this study was to evaluate the role of different formulations and different administration kinetics of antenatal corticosteroid therapy on fetal heart rate.


METHODS
One hundred five patients who were at high risk for preterm delivery were assigned randomly to receive two injections of betamethasone acetate + phosphate, four injections of betamethasone phosphate, or four injections of dexamethasone phosphate. Computerized fetal heart rate was recorded daily through day 4.


RESULTS
The three formulations did not differ in their effect on fetal heart rate, which varied significantly as a function of the time of injection. During treatment (day 0-day 1), fetal heart rate variability increased (+9%, P <.05), as did the number of fetal movements felt by the mother (+60% at day 0, P <.001). After treatment (day 2-day 3), variability fell significantly (-14%, P <.01), as did accelerations (-35% at day 2, P <.01). No modifications were still detectable on day 4.


CONCLUSIONS
Antenatal corticotherapy is responsible for two different phases of fetal heart rate modifications that do not vary according to the corticosteroid or the dosage regimen.
Subtil
Damien
D
Department of Obstetrics, Gynecology, and Neonatal Care, Hôpital Jeanne de Flandre, University of Lille, France. d-subtil@chru-lille.fr
Tiberghien
Pauline
P
Devos
Patrick
P
Therby
Denis
D
Leclerc
Gilles
G
Vaast
Pascal
P
Puech
Francis
F
D001623:Betamethasone / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D003907:Dexamethasone / Q000627:therapeutic use*; D005260:Female; D005324:Fetal Movement / Q000187:drug effects; D005938:Glucocorticoids / Q000627:therapeutic use*; D006340:Heart Rate, Fetal / Q000187:drug effects*; D006801:Humans; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D011247:Pregnancy; D011295:Prenatal Care; D013997:Time Factors
D005938:Glucocorticoids; C018230:betamethasone acetate phosphate; C028994:betamethasone sodium phosphate; D003907:Dexamethasone; D001623:Betamethasone