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.
OBJECTIVE
To determine whether isosorbide mononitrate (IMN), self-administered vaginally by women at home, improves the process of induction of labour.


METHODS
Randomised double blind placebo-controlled trial.


METHODS
Large UK maternity hospital.


METHODS
Nulliparous women with a singleton pregnancy, cephalic presentation > or = 37 weeks gestation, requiring cervical ripening prior to induction of labour.


METHODS
IMN (n = 177) or placebo (n = 173) self-administered vaginally at home at 48, 32 and 16 hours prior to the scheduled time of admission for induction.


METHODS
Admission to delivery interval and women's experience of induction of labour.


RESULTS
IMN did not shorten the admission to delivery interval as compared with placebo [mean difference of -1.6 hours (95% CI -5.1,1.9, P = 0.37)], despite being more effective than placebo in inducing a change in Bishop score [mean difference of 0.65 (95% CI 0.14,1.17, P = 0.013)]. While both groups found the overall experience of home treatment to be positive, (mean score of 3.8/10 +/- 2.3/10 for the IMN group, where 1 = extremely good and 10 = not at all good) women in the placebo group found it marginally more positive than those in the IMN group (just over half a unit on a 10-point scale, P = 0.043). There were no differences between the groups in the pain or anxiety experienced or willingness to take the treatment in a subsequent pregnancy.


CONCLUSIONS
IMN self-administered vaginally at home does not shorten admission to delivery interval despite a significant effect on cervical ripeness assessed using the Bishop score. However, women report positive views on cervical ripening at home, and the setting deserves further investigation.
Bollapragada
S S
SS
Maternal and Reproductive Medicine, Division of Developmental Medicine, University of Glasgow, Glasgow Royal Infirmary, Glasgow, UK.
MacKenzie
F
F
Norrie
J D
JD
Eddama
O
O
Petrou
S
S
Reid
M
M
Norman
J E
JE
D000282:Administration, Intravaginal; D000328:Adult; D000553:Ambulatory Care / Q000379:methods* / Q000523:psychology; D020070:Cervical Ripening / Q000187:drug effects*; D004311:Double-Blind Method; D005260:Female; D006699:Home Care Services; D006801:Humans; D007548:Isosorbide Dinitrate / Q000008:administration & dosage / Q000031:analogs & derivatives*; D007751:Labor, Induced / Q000379:methods*; D020030:Nitric Oxide Donors / Q000008:administration & dosage*; D017060:Patient Satisfaction; D011247:Pregnancy
D020030:Nitric Oxide Donors; D007548:Isosorbide Dinitrate; C030397:isosorbide-5-mononitrate