Midtrimester Mifepristone/Misoprostol Mifepristone pretreatment markedly increases the abortifacient efficacy of gemeprost and misprostol. The mean interval from start of the prostaglandin to fetal expulsion is reduced to 6 to 9 hours, much shorter than with misoprostol alone (360). Mifepristone, 200 mg, is just as effective for this purpose as 600 mg (361). A common protocol was developed using mifepristone and misoprostol that is now recommended both by the Royal College of Obstetricians and Gynecologists (RCOG) and the World Health Organization (WHO) (358,362). Most women are cared for as hospital day-patients without need for overnight admission, a marked improvement over the labor induction methods of the past that often required 2 to 3 days of hospitalization. The protocol involves giving 200 mg of mifepristone orally on day 1. The patient returns 36 to 48 hours later for completion of the abortion with misoprostol. She is given 800 μg vaginally, and then 3 hours later, 400 μgisgiven orally and repeated at 3 hour intervals up to four doses. Efficacy is greater when the interval from mifepristone to starting misoprostol is at least 36 to 38 hours (363). Mean times from the start of misoprostol to fetal expulsion are 5.9 to 6.6 hours (358,360). The RCOG mandates that legal abortion must not be allowed to terminate in a live birth. Use of a feticide is required at 21 weeks (364). In the series by Ashok et al. of 1,002 women treated with the mifepristone/misoprostol protocol, described above, patients who had not expelled the fetus after 24 hours from start of the misoprostol were given an additional dose of 200 mg mifepristone at midnight, then started on another course of five doses of misoprostol the next morning, 800 μg initially, then 400 μg at 3 hour intervals, all given vaginally (360). About 8% needed a curettage procedure for retained placenta. Hemorrhage requiring transfusion occurred in about 1% of patients, usually from retained placenta.
Combination of Induction Hern developed a procedure that combines a feticidal injection of digoxin with serial insertion and Assisted Delivery of multiple laminaria tents over 2 to 3 days, followed by amniotomy, placement of misoprostol in the lower uterine segment, and intravenous oxytocin to induce labor, and then an assisted delivery (365). The procedure was successful in a large case series at 18 to 34 weeks with very few complications.
High-Dose Oxytocin Oxytocin in very high doses is as effective as dinoprostone at 17 to 24 weeks of pregnancy, but is not equal to the mifepristone/misoprostol regimen described above (365). Patients initially receive an infusion of 50 U of oxytocin in 500 mL of 5% dextrose and normal saline over 3 hours; 1 hour of no oxytocin, followed by a 100-U, 500-mL solution over 3 hours; another hour of rest; and then a 150-U, 500-mL solution over 3 hours, alternating 3 hours of oxytocin
Table 10.11 Complications of 2,935 Midtrimester Dilation and Evacuation Abortion and Intervention Rates on a Referral Service
From Frick AC, Drey EA, Diedrich JT, et al. Effect of prior cesarean delivery on risk of second-trimester surgical abortion complications. Obstet Gynecol 2010;115:762 [Table 2], with permission.