A randomized clinical trial comparing intravaginal glyceryl trinitrate (nitric oxide donor) plus artificial sweeping of membrane versus artificial sweeping of membrane alone for cervical ripening at term pregnancies with unfavourable cervix

Introduction: There are several reasons to have post-dated pregnancies in uncomplicated pregnancies in labour wards. The policy of cervical ripening at term will reduce the risk and their complications associated with postdate pregnancies. Artificial sweeping of membranes and nitric oxide donors are useful cervical ripening methods used across the world. This study was carried out to compare the efficacy of cervical ripening by administration of intravaginal glyceryl trinitrate plus artificial sweeping of membranes versus artificial sweeping of membranes alone. Objectives: To compare of the efficacy, the spontaneous onset of labour rate, the labour outcome, the duration from induction to the delivery time of baby and adverse maternal and fetal outcomes of cervical ripening by administrating of intravaginal glyceryl trinitrate combined with artificial sweeping of membranes versus artificial sweeping of membranes alone. Methodology: This was a double blinded randomized clinical trial carried out in a major obstetric unit in Sri Lanka. Having excluded the subjects according to the exclusion criteria, rest of the sample was divided into cases and controls. Sample randomization done by using stratified block randomization technique with sealed envelope. Artificial sweeping of membranes done together with intravaginal Glyceryl trinitrate was inserted for the cases and artificial sweeping of membranes alone was performed for the control group. Number of Spontaneous onsets of labour, improvement of the modified Bishop’s Score, delivery time and labor outcome were assessed. Data were analyzed by using SPSS software. Results: Mean age, parity and gestational age were matched in both intervention and control group. Number of mothers with spontaneous onset of labour within 24 hours were significantly increased (p<0.001) in both primi and multiparous women in therapeutic arm compare to controls. The modified Bishop's score was improved in both primi and multi women, in addition, multiparous mothers in therapeutic arm showed the statistically significant improvement (p<0.001) of the modified Bishop's score compare to control arm. There was reduction in the time duration from induction to delivery of baby in both multi and primi therapeutic arms, and reduction is statistically significant in multiparous (p=0.01) women, but reduction is not significant in primi mothers. There were no significant differences in mode of delivery, maternal and fetal adverse out comes in between intervention and control arms other than the headache (P<0.001), of which significantly reported in therapeutic arm. Conclusion and recommendation: Intravaginal glyceryl trinitrate combined with artificial sweeping of membranes is associated with increased rate of spontaneous onset of labour at term, improvement of modified Bishop's score and reduction of time duration from induction to delivery in term pregnancies. It had minimal maternal and fetal adverse outcome. Further studies should be carried out to find optimal dose and frequency, long term safety, specific side effect and possibility of using in outpatient department relation to to the glyceryl trinitrate intravaginal route.