RESUMEN
OBJECTIVE: The purpose of this study was to evaluate the effects of exogenous administration of PGE2 upon the components of the biophysical profile. METHODS: The study group included 17 nulliparas at > or = 38 weeks gestation, with a Bishop score of < or = 4, requiring induction of labor. A controlled release vaginal pessary containing 10 mg of PGE2, designed to release hormones at approximately 0.8 mg per hour in vitro, was used for 12 hours of cervical ripening. The BPP was performed by the same sonographer at three intervals: prior to pessary insertion, at 6 hours, and 12 hours. RESULTS: None of these patients had membrane rupture or went into spontaneous labor during the ripening process. All patients subsequently required amniotomy and oxytocin. The proportion of patients scoring 2 points for fetal breathing movements decreased from 59% at baseline to 0% at 12 hours, P < 0.0005, and the proportion of patients with fetal body movements decreased from 100% at baseline to 25% at 12 hours, P < 0.0005. However, the other components of the biophysical profile were not affected. The mean maternal plasma PGE2 metabolite concentrations were 235 pg/ml, 475 pg/ml, and 466 pg/ml at 0, 6 and 12 hours, respectively, P < 0.005. CONCLUSIONS: In term patients, vaginal administration of the PGE2 pessary was associated with improved Bishop score over 12 hours and significant increases in maternal plasma PGEM levels at 6 hours and 12 hours. These changes were inversely related to fetal breathing and body movements.