Evaluation of nitric acid donor, transdermal glycerol trinitrate patches for facilitating cervical ripening: a randomised controlled trial.

Purpose: To evaluate the efficacy and safety of transdermal glycerol trinitrate skin patches as an additive and effective agent for facilitating cervical ripening for labour induction. Methods: This was a double-blinded prospective randomised clinical trial carried out in a major obstetric unit in India. Women who planned for labour induction were randomly allocated for induction either by combined application of glycerol trinitrate skin patches [GTN patch] and intracervical dinoprostone gel or by the gel only. Sample randomisation was done using a stratified block randomisation technique with a sealed envelope. The numbers designating the group allocation sequence were concealed from doctors, research staff, and investigators. Six hourly improvements were assessed in the modified Bishop's score, induction-delivery time interval, the need for oxytocin, maternal side effects and foetal outcomes. Data were analysed using SPSS software. Results and discussion: Recruitment Bishop scores, parity and gestational age were matched in both cases and the control group. The modified Bishop's score was statistically improved in study groups, as evidenced compositely and irrespective of parity. The two groups appeared to have no significant differences regarding other outcomes. The additional application of the GTN patch seems helpful to accelerate the progress of labour but could not yield any favourable labour outcome. The GTN patch does not impose additional feto-maternal adverse effects apart from increased incidences of headaches. [ABSTRACT FROM AUTHOR]