Examining the Evidence
Q Is misoprostol as effective as surgery for early pregnancy failure?
<huc>A</huc> Misoprostol is slightly less effective than vacuum aspiration, but is well tolerated by patients.
About 1 in 5 women experience “early pregnancy failure,” a term that includes incomplete abortion, inevitable abortion, anembryonic gestation, and embryonic or fetal death. Since misoprostol was first described in 1997 as a single agent for evacuating the uterus in early pregnancy failure,1 many cohort studies have evaluated it for this purpose. Zhang et al provide level I evidence that intravaginal misoprostol is effective for uterine evacuation in early pregnancy failure.
This study involved 652 women at 10 weeks’ gestation or less (crown-rump length of ≤40 mm or an average gestational sac diameter of ≤45 mm) who were randomized in a 3:1 ratio to misoprostol 800 μg vaginally (repeated in 2 days if necessary) or vacuum aspiration. Complete expulsion of the products of conception in the misoprostol group occurred in 71% of women by the second day after the initial dose and in 84% of women within 1 week.
Although the 1-week failure rate (16%) was higher than that for vacuum aspiration (3%), this was a “noninferiority trial.” That is, Zhang et al recognized that medical treatment was unlikely to surpass the success rate of surgery, so they calculated an absolute difference of 18% as the maximum difference that would demonstrate noninferiority of misoprostol.
This treatment is not for every patient. However, for women at gestational ages of less than 10 to 11 weeks who prefer to avoid a trip to the operating room, misoprostol is an attractive option.
Follow this protocol:
- provide oral analgesia (eg, ibuprofen and codeine)
- advise patients when to seek emergency care (heavy bleeding for more than 1 to 2 hours or pain unrelieved by medication)
- order a follow-up ultrasound exam.
More cost-effective than surgery
Although expense was not addressed in this study, misoprostol is more cost-effective than uterine curettage. Because only 1 in 7 women treated with misoprostol ultimately require surgery and at least one third of women choosing expectant management do not have a spontaneous abortion in a reasonable amount of time, misoprostol may be more cost-effective than expectant management.
Side effects had little impact
Of the patients treated with misoprostol, three quarters said they would opt to use it again, and four fifths said they would recommend it to others. These proportions were similar for the subgroup who had undergone surgical management for failure of an earlier pregnancy.
This finding is noteworthy because misoprostol caused more side effects. Women taking it had more bleeding (measured by the change in hemoglobin concentrations), gastrointestinal side effects (nausea, vomiting, and diarrhea), and pain.
The author reports no financial relationships relevant to this article.
1. Creinin MD, Moyer R, Guido R. Misoprostol for medical evacuation of early pregnancy failure. Obstet Gynecol. 1997;89:768-772.