QUEBEC CITY — Oral misoprostol appears to be as effective as oxytocin by injection in reducing blood loss at delivery, but is associated with an increased need for additional oxytocic drugs, according to a randomized, controlled trial presented in poster format at the annual meeting of the Society of Obstetricians and Gynaecologists of Canada.
“Oral misoprostol may be used to reduce postpartum bleeding, particularly in areas where injectable oxytocic drugs are unavailable,” reported lead investigator Thomas Baskett, M.B., professor of obstetrics and gynecology at Dalhousie University in Halifax, Nova Scotia.
The synthetic PGE1 analogue has the advantage of being a cheap, stable, and orally administered uterotonic agent. “The main application for this is in developing countries, where they don't have personnel looking after women who can inject, or where there is no equipment or oxytocics to do so,” he said in an interview, adding that it might also have applications in rural communities if injectable oxytocics were not available.
Misoprostol has a role as second-line therapy if other injectables fail. “You might not use it routinely for active management of the third stage to reduce or prevent blood loss, but if bleeding occurs, then you can give misoprostol either orally or rectally with ease, and it's easy to have it stored in nursing stations or hospitals,” he said.
To assess efficacy of both agents, he and his colleagues compared 311 women given 400 mcg of oral misoprostol and 311 women who were given intravenous oxytocin, 5 units given after delivery of the anterior shoulder of the fetus. Researchers looked at women who had cephalic presentation and delivered vaginally, between 2000 and 2003 at the IWK Health Centre in Halifax. Those who had a multiple pregnancy, placenta previa, abruptio placentae, coagulation abnormalities, cesarean section, or severe asthma were excluded.
The primary outcome of at least a 10% drop in hematocrit at 24 hours' post partum was not clinically or statistically significantly different between the groups, and occurred in 10 of 291 (3.4%) of oxytocin patients, compared with 11 of 294 (3.7%) in the misoprostol group.
A total of 20 patients in the intravenous oxytocin group and 17 in the oral misoprostol group had missing hematocrit and hemoglobin values.
Of the secondary outcomes, 8.9% of oxytocin patients had a hematocrit drop of at least 30%, compared with 10.2% of patients in the misoprostol group.
Blood loss that was greater than 1,000 mL occurred in 2.3% of the oxytocin group and 4.5% of the misoprostol group. Additional uterotonics were required in 40.5% of those in the oxytocin group compared with 51.1% of those in the oral misoprostol group.
Researchers noted that the number of patients receiving additional oxytocics was high in both groups, and this was most likely due to the prevailing routine at the hospital of giving an intravenous infusion of oxytocin following the initial bolus dose at delivery.
Side effects of shivering and fever were present only in patients in the misoprostol group at the dose used, but were not clinically troublesome, the researchers noted. “Most of the trials that have found often upsetting shivering were with 600 mcg, and our study was with 400 mcg,” Dr. Baskett said in an interview.
The study was conducted to substantiate that it is reasonable to use the 400-mcg dose if the local circumstances and resources dictate that it be used, he noted.