Randomised 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 investigated whether this drug is associated with fewer side-effects than prostaglandins when used to ripen the cervix before first-trimester surgical termination of pregnancy, and assessed whether the extent of cervical ripening it induces is clinically sufficient.


METHODS
66 primigravid women scheduled for surgical termination were assigned to receive before surgery, per vaginam, isosorbide mononitrate 40 mg or 80 mg, or the prostaglandin analogue gemeprost 1 mg. The primary measured outcome was onset of new symptoms before termination of pregnancy.


RESULTS
More women remained symptom-free after isosorbide mononitrate than after gemeprost (28/44 [64%] vs 3/22 [14%], p<0.005). Pretreatment with gemeprost resulted in abdominal pain in 73% of women and vaginal bleeding in 32% compared with 3% and 0%, respectively, after isosorbide mononitrate, whereas, more women developed headache after isosorbide mononitrate (27%) than after gemeprost (0%). Cervical resistance and measured intraoperative blood loss were lowest after pretreatment with gemeprost. The measured cervical resistance and intraoperative blood loss with either dose of isosorbide mononitrate did not differ from those in a comparison group of 22 parous women not in the randomised trial.


CONCLUSIONS
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 decreases cervical resistance. Isosorbide mononitrate could be used as an alternative to gemeprost for this indication.
Thomson
A J
AJ
Department of Obstetrics and Gynaecology, University of Glasgow, UK.
Lunan
C B
CB
Ledingham
M
M
Howat
R C
RC
Cameron
I T
IT
Greer
I A
IA
Norman
J E
JE
D000020:Abortifacient Agents, Nonsteroidal / Q000009:adverse effects / Q000627:therapeutic use*; D000028:Abortion, Induced; D000328:Adult; D000527:Alprostadil / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D020070:Cervical Ripening / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007548:Isosorbide Dinitrate / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D020030:Nitric Oxide Donors / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D011247:Pregnancy; D011261:Pregnancy Trimester, First
D000020:Abortifacient Agents, Nonsteroidal; D020030:Nitric Oxide Donors; C021182:gemeprost; D000527:Alprostadil; D007548:Isosorbide Dinitrate; C030397:isosorbide-5-mononitrate