RANDOMIZED TRIAL OF NITRIC-OXIDE DONOR VERSUS PROSTAGLANDIN FOR CERVICAL RIPENING BEFORE FIRST-TRIMESTER TERMINATION OF PREGNANCY

Background Vaginal administration of the nitric oxide donor isosorbide mononitrate can induce effective ripening of the human cervix. We inv estigated whether this drug is associated with fewer side-effects than prostaglandins when used to ripen the cervix before first-trimester s urgical termination of pregnancy, and assessed whether the extent of c ervical ripening it induces is clinically sufficient. Methods 66 primi gravid women scheduled for surgical termination were assigned to recei ve before surgery, per vaginam, isosorbide mononitrate 40 mg or 80 mg, or the prostaglandin analogue gemeprost 1 mg. The primary measured ou tcome was onset of new symptoms before termination of pregnancy. Findi ngs More women remained symptom-free after isosorbide mononitrate than after gemeprost (28/44 [64%] vs 3/22 [14%], p<0.005). Pretreatment wi th gemeprost resulted in abdominal pain in 73% of women and vaginal bl eeding in 32% compared with 3% and 0%, respectively, after isosorbide mononitrate, whereas, more women developed headache after isosorbide m ononitrate (27%) than after gemeprost (0%). Cervical resistance and me asured intraoperative blood loss were lowest after pretreatment with g emeprost, The measured cervical resistance and intraoperative blood lo ss with either dose of isosorbide mononitrate did not differ from thos e in a comparison group of 22 parous women not in the randomised trial . Interpretation Pretreatment with isosorbide mononitrate to ripen the cervix before first-trimester termination of pregnancy is associated with fewer side-effects than gemeprost treatment and adequately decrea ses cervical resistance. Isosorbide mononitrate could be used as an al ternative to gemeprost for this indication.