The purpose of this study was to determine whether isosorbide mononitrate (IMN) self administered by women on an outpatient basis improves the process of induction of labour by resulting in a shorter inpatient stay before delivery, decreased costs to the health service and greater maternal satisfaction with ripening and induction of labour, compared with placebo treatment.
The study was funded by WellBeing of Women. Three hundred and fifty women were randomised at the Princess Royal Maternity Hospital, Glasgow to receive treatment with ISM 40 mg or placebo.
IMN did not shorten the admission to delivery interval as compared with placebo despite being more effective than placebo in inducing a change in Bishop score. While both groups found the overall experience of home treatment to be positive, women in the placebo group found it marginally more positive than those in the IMN group. There were no differences between the groups in the pain or anxiety experienced or willingness to take the treatment in a subsequent pregnancy.
Shrikant Bollapragada, Fiona Mackenzie, John Norrie, Stavros Petrou, Margaret Reid, Ian Greer, Inass Osman and Jane E Norman. IMOP: randomised placebo controlled trial of outpatient cervical ripening with isosorbide mononitrate (IMN) prior to induction of labour – clinical trial with analyses of efficacy, cost effectiveness and acceptability. BMC Pregnancy and Childbirth 2006; 6:25
Bollapragada, S.,MacKenzie,F.,Norrie,J.,etal.,2009.Randomised placebo controlled trial of outpatient (at home) cervical ripening with isosorbide mononitrate (IMN) prior to induction of labour—clinical trial with analyses of efficacy, and acceptability;the IMOP Study. British Journal of Obstetrics and Gynaecology 2009; 116 (9): 1185–1195.