Evaluating the efficacy of outpatient use of isosorbide mononitrate on cervical ripening in pregnant women with unfavourable cervix

Abstract

The aim of the present study was to evaluate the efficacy of outpatient administration of nitric oxide donor isosorbide mononitrate for cervical ripening. A randomised clinical trial was performed on term pregnant women with Bishop Score < 6. In the case group, Isosorbide-5-mononitrate capsule and in the control group, placebo was inserted in the posterior vaginal fornix for two consecutive days. The main outcomes were increases in Bishop Score after 48 hours of intervention, number of vaginal deliveries and interval from intervention to delivery.

There was a significant increase of the mean Bishop score in the isosorbide group [3.57 ± 1.12 VS 1.54 ± 1.42 respectively (p = .001)]. The other outcome variables did not show a significant difference between the two groups except for headache which was significantly more in the case group. No cases of tachysystole were observed in the two groups. Additionally, haemoglobin levels after delivery did not show a significant difference between the two groups.

Impact statement:

• What is already known on this subject? Cervical ripening in women with an unfavourable cervix and having an indication for induction of labour is an important issue in modern obstetrics. Different methods have been used for cervical ripening and induction of labour including mechanical (i.e. laminaria tents, Dilapan-S, foley catheter), medical (i.e. PGs) and supportive methods. There is no consensus on the best option for cervical ripening

• What will the results of this study add to the current knowledge of this subject? Outpatient administration of nitric oxide could affect cervical ripening without a significant improvement in the duration of different stages of labour, intervention to delivery interval and number of vaginal deliveries.

• What are the implications of these findings for clinical practice and/or further research? Due to the contradictory results of various studies, more studies should be performed with greater sample size to evaluate nitric oxide donor isosorbide mononitrate effect on labour duration and reducing caesarean deliveries. Additional data is needed to assess the real impact of NO donors on different stages of labour and its implications.

Keywords:

• Pregnancy
• delivery
• Bishop Score
• nitric oxide
• cervical ripening
• isosorbide mononitrate
• labour
• IRCT ID: IRCT20091023002624N27

Disclosure statement

No potential conflict of interest was reported by the author(s).