Last August, I argued against ACOG's current position on inducing labor with misoprostol, which is that misoprostol is safe 'when used appropriately' (p. 387), by which ACOG means provided it is used in doses no greater than 50 micrograms in women with an unscarred uterus. In March, I started work on the induction chapter for the new edition of Obstetric Myths Versus Research Realities, and I decided to see if I could find evidence that ACOG's confidence was misplaced. I looked for reports of misoprostol catastrophes occurring in U.S. hospitals in women with unscarred uteruses who received no more than 50 microgram doses of misoprostol. I found 11 cases fitting my criteria. Two were single case reports: a uterine rupture leading to hysterectomy in a woman induced solely with two 25 microgram vaginal doses of misoprostol, and a uterine rupture leading to stillbirth and hysterectomy in a woman induced solely with one 25 microgram vaginal dose. The other nine were reported in a case series of severe adverse events following misoprostol induction vaginally or, in one case, orally. All nine women experienced uterine hyperstimulation, which in seven cases was reported as accompanied by severely abnormal fetal heart rate, meconium, or both. The nine cases of hyperstimulation resulted in a total of two cases of uterine rupture, five cases of permanent fetal neurologic injury, two perinatal deaths, and three maternal deaths. One woman with uterine rupture experienced disseminated intravascular coagulation, a life-threatening consequence of severe hemorrhage, and three women had diagnoses of amniotic fluid embolism (AFE). The AFE cases resulted in a maternal death, a maternal death and a brain injured child, and a maternal and perinatal death among the mother-baby pairs. We probably have a twelfth case in comment #17 to the original blog post, but not enough information is given to be sure. (Maddy Oden also posted a comment, but Tatia Oden French's case is the third of the three AFE cases reported in the case series, a case, by the way, in which Maddy tells me that the coroner's report mentions AFE but lists the cause of maternal death as 'natural causes: cardiac arrest.')

We're not done yet. I also ran across a study comparing 95 pre-eclamptic women undergoing pre-induction cervical ripening with vaginal misoprostol with 108 women having ripening with prostaglandin E2. Among women receiving misoprostol, 18% had cesareans for fetal heart rate abnormalities, A.K.A. fetal distress, versus 8% of those having prostaglandin E2, and 14% having misoprostol experienced placental abruption (the placenta detaches partially or completely before delivery) versus 2% receiving prostaglandin E2. So it isn't just women with cesarean scars who are at especially high risk with misoprostol inductions but women with severe hypertension as well.

I don't know about you, but if there were a compelling medical reason why I needed labor induced - and most inductions do not fall in this category - and the situation was, moreover, of such concern that induction could not wait for cervical readiness to labor, I would insist on using some means other than misoprostol.

Published: May 09, 2010

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