Pregnancy after Uterine artery embolization for uterine fibroids

Abstract & Commentary

By John C. Hobbins, MD, Professor and Chief of Obstetrics, University of Colorado Health Sciences Center, Denver, is Associate Editor for OB/GYN Clinical Alert.

Dr. Hobbins reports no financial relationship to this field of study.

Synopsis: Uterine artery embolization has become an increasingly popular procedure for treatment of uterine fibroids, but there are only a few studies in the literature dealing with the outcomes of pregnancy following this form of modestly invasive therapy.

Source: Walker WJ, et al. Pregnancy after uterine artery embolization for leiomyomata: A series of 56 completed pregnancies. Am J Obstet Gynecol. 2006;195:1266-1271.

In a recent paper, Walker and McDowell contacted 1200 patients having had this procedure since 1996 at either the Royal Surrey County Hospital or the London clinic. One hundred eight women had tried to become pregnant and 33 succeeded at least once. In total, the authors had data on 56 completed pregnancies.

There were 33 live births (58.9%) in this group of patients. Also, there were 17 (30.4%) miscarriages, 6 preterm births (18.2%), 2 (3.6%) stillbirths, and 1 ectopic pregnancy.

Commentary

Since embolization works quite well in shrinking fibroids by starving them, one cannot help but wonder what the temporary interruption of a portion of the uterine circulation will do to a uterus that is later being asked to support a fetus and placenta that are substantially larger and more demanding than the fibroid that was embolized. In fact, in a recent review of fibroid embolization by Olive et al in 2004, it was recommended that, until further evidence is available, those contemplating later pregnancy should have another form of therapy for uterine fibroids.

A glance at the results in which the incidence of miscarriage, preterm birth, and, simply, the chances of not having a successful pregnancy, are well above that of the overall population, might well raise some concern about the procedure. However, those having this procedure are not the "overall population." For example, the average age of the patients in the study was 37.5 years and 58% of these pregnancies were in those who were never pregnant before (a loaded deck for pregnancy-related complications). The average age of those having miscarriages was close to 39 years. Although the rate of spontaneous abortion is stated to be 10 to 15%, this increases two- to three-fold for those who are 40 years of age or older. Also, one would expect at least a 2 fold increase in preterm birth in women over 35, so the 18% rate in this study roughly matches up to what would be expected in this population.

Last, the Cesarean section rate is quite high at 72.7 % in these patients. However, the major indication for the Cesarean sections was "fibroid"—a self-fulfilling situation. I would guess that in the USA the Cesarean section rate in a group of women in their first pregnancies, whose average age is 38, would be close to that figure.

So, my take on this study is that the glass is a little more than half full for patients wishing to become pregnant after uterine artery embolization, but whatever problems they will encounter are less about the embolization of their fibroids and more about their inherently greater predisposition toward adverse pregnancy outcome.

References

  1. Walker WJ, et al. Pregnancy after uterine artery embolization for leiomyomata: A series of 56 completed pregnancies. Am J Obstet Gynecol. 2006;195:1266-1271.
  2. Olive D, et al. Nonsurgical management of leiomyomata: impact on fertility. Cur Opin Obstet Gynecol. 2004;16:239-243.