Comparison of oestradiol and prostaglandin E2 vaginal gel for ripening the unfavourable cervix

Abstract

I was most interested in the results reported by Mr. Phillip M. Tromans and his colleagues (February 28 p 679) comparing the ability of estradiol and (PGE2) prostaglandin E2 to ripen the unfavorable cervix before induction of labor. Following work with Dr. A.A. Calder on the ripening effect of estradiol on the unfavorable cervix I compared the effect of estradiol (150 mg in 6 ml hydroxyethylmethylcellulose gel) with that of PGE2 (400 mcg in 6 ml hydroxyethylmethylcellulose gel). There were 25 primigravidas in each group with cervical scores of 3 or less and the treatment was given extraamniotically the night before planned induction. There were no significant differences in the maternal age height weight or length of gestation and all patients had a singleton cephalic presentation. The results are shown in an accompanying table. The indications for cesarean section were cephalopelvic disproportion in both patients in the PGE2 group and fetal distress in 2 cases and failure to progress in the estradiol group. The only statistically significant difference between the 2 groups was in the number of patients going into labor following cervical ripening. 12 of the 25 patients treated with PGE2 went into labor but only 1 of the estradiol group did so (p=0.0005). This lack of uterine stimulation may make estradiol pretreatment preferable where placental function is suspect. Although the vaginal application may be more convenient than the extraamniotic route the high cesarean section rate reported (23% and 27%) by Mr. Tromans and his colleagues may make further studies on the best route of application worth while as the cesarean section rates in my series were 8% and 12%. Insertion of a Foley catheter may change the shape of the cervix. In a study comparing routes of administration of PGE2 to ripen the cervix Toplis and Sims found that the incidence of cesarean section following 3 mg vaginal paste was 15% compared with only 5% for 500 mcg given extraamniotically. (Authors modified)