Cervical ripening with combinations of vaginal prostaglandin F2-alpha estradiol, and relaxin.

The first of a 2-part trial consisted of a double-blind randomized pilot study in which 4 groups of 10 patients near term received 1 of the following hormonal combinations in a vaginal gel 15 hours before surgical induction of labor: 1) prostaglandin F2 alpha (PGF2 alpha) and relaxin; 2) relaxin and estradiol; 3) estradiol and PGF2 alpha; and 4) relaxin, estradiol, and PGF2 alpha. In each group the mean cervical score improved after treatment; the relaxin/PGF2 alpha combination was associated with the greatest improvement in cervical score (4.8). The highest incidence of subsequent labor was also seen in the relaxin/PGF2 alpha group (40%). However, with the exception of the latter group, the clinical effects of these hormonal combinations were neither greater nor smaller than the previously published effects of these hormones used individually in similar circumstances. The second part of the study further explored the possibility of an additive effect of relaxin and PGF2 alpha in combination as suggested by the pilot study, and an additional 40 patients were given this combination. Analysis of these larger numbers showed no additive effect when these hormones were used in combination compared with when they were used individually. Thus, in the circumstances described, there is no clinical advantage to the concurrent administration of any combination of relaxin, PGF2 alpha and estradiol with regard to cervical ripening and/or the initiation of parturition.