[Comparison of isosorbide dinitrate and dinoprostone for induction of labor in term pregnancy].

Background: it has been suggested that nitric oxide generators, such as isosorbide dinitrate, may be an alternative to mimic the effects of signal transduction mechanisms leading to cervical ripening, without affecting uterine contractility.

Objective: to compare the isosorbide dinitrate and dinoprostone for induction of labor in term pregnancy.

Material And Methods: in a randomized controlled blinded clinical trial, we studied 66 patients divided into 2 groups: 33 patients were given 20 mg of isosorbide dinitrate and to the other 33 were administered 0.5 mcg of dinoprostone; in both groups the drugs were administered vaginally each 6 h and at maximum 3 times. It was carried out a cardiotocographic study in order to determine the presence or absence of uterine activity and to exclude disorders of the fetal heart frequency; it was performed a vaginal examination to assess cervical conditions determining the Bishop score at 0, 6 and 12 h.

Results: there were no differences between the groups in the determinations of mean arterial pressure, maternal heart frequency, fetal heart frequency and Bishop score registered at 6 y 12 h followed the drugs administration. The time of delivery was 20.7 +/- 1.8 h in the group of women treated with dinoprostone; and 16.3 +/- 1.4 h in women treated with isosorbide dinitrate (p=0.032). The cost was higher in women treated with dinoprostone ($560 vs $12, respectively, p=0.001). There was no difference between the groups related to: frequency of meconium stained liquid (p=1.000), mode of delivery by caesarean section (p=0.918), Apgar score at 1 minute (p=0.764) and 5 minutes (p=0.294) and mother discharged with healthy baby (p=1.000).

Conclusions: the isosorbide dinitrate is associated with lower duration of labor compared with dinoprostone. There was no difference in the maternal-fetal outcome by using whatever drug.