A new study from Canada has found that women who undergo a treatment called uterine artery embolization, or UAE, for uterine fibroids can successfully become pregnant afterwards.1
A Surprising Outcome
But that wasn't the original objective. The findings were pulled from a much larger study that the researchers from the University of Toronto had begun to determine whether UAE might be a more favorable approach for women who were candidates for a hysterectomy, explained Gaylene Pron, PhD, an epidemiologist in the department of Public Health Sciences at the university, and the study's chief investigator.
"They had been advised, at minimum, by three different gynecologists that the only solution was a hysterectomy for them, which they didn't want," Pron told Priority Healthcare.
"While we were following these women up, over time … we had a number of women who were getting pregnant," she said. "This was a surprise finding. And the fact that three of these women became pregnant twice was even more dramatic." Many of the participants were older, and had had "difficult reproductive histories" prior to undergoing UAE, Pron pointed out.
How Embolization is Performed
UAE is aimed at blocking the arteries that supply blood to the fibroids, causing them to shrink. It's performed on a minimally invasive basis; patients are sedated, and they remain conscious throughout the procedure. Using local anesthesia, the technique is performed by feeding a catheter through the femoral artery from the groin area to the uterus. An interventional radiologist monitors the procedure using x-ray imaging. Once the catheter is in place, the doctor then injects tiny plastic particles about the size of grains of sand into the artery that supplies blood to the fibroids. This eventually cuts off blood flow, and causes the fibroid tumor to shrink.2
Fibroids are benign tumors that are often painless or absent of other symptoms. The tumors are never cancerous, and are not associated with an increased risk of uterine cancer. But they are among the most common tumors in women.3
A Study Detour
Given the pregnancies that were observed in the women undergoing UAE in their larger study, Pron and her colleagues decided to take a different route, setting out to measure how often pregnancy occurred in women who had undergone the procedure. "The use of embolization for fertility preservation is rapidly becoming an issue, as more women of childbearing age elect for transcatheter management of their symptomatic [fibroids]," the researchers wrote. "To date, most centers have advocated a cautious approach in dealing with these patients, and have generally advised against uterine embolization until more is known."
The original research involved 555 women who underwent UAE between 1998 and 2000 as an alternative to hysterectomy. While the average age of the participants was 43, nearly a third of them were under age 40.
Each patient was followed up by telephone interview, and each of their obstetric medical records was reviewed by Pron's team.
They learned that 21 of the women conceived after the embolization procedure, and three additional women became pregnant twice. Twenty-three of the 24 pregnancies began with spontaneous conceptions, and one woman who conceived had undergone in-vitro fertilization. "The efficacy of in-vitro fertilization in women having undergone embolization is also an emerging consideration for both infertile women with [fibroids], and physicians providing these treatments," Pron and her team wrote.
Pron and her colleagues also learned that there were 4 miscarriages among the women who became pregnant. But that 17% risk was about the same as what women in the general population face, the researchers noted.
Of 18 live births that resulted, 14 were carried to term, Pron's group found, and 4 were preterm births. There were also 9 vaginal deliveries, and 9 C-sections performed in the group.
Complications of UAE
Surprisingly, Pron and her team found that there was an abnormally high risk of placental abnormalities in the group of pregnant women. Two women developed a condition known as placenta previa (pluh-SEN-tuh PREH-vee-uh), in which the placenta becomes abnormally located over the opening to the birth canal. One other woman was diagnosed with a condition known as placenta membranacea (pluh-SEN-tuh mem-brane-AY-kee-uh), in which the placenta becomes abnormally thin and lines the entire uterus.
"It is uncertain whether abnormal placentas observed in our pregnancies are directly related to embolization," Pron and her team wrote. "The fact that menstruation resumed after embolization in all of these women, however, suggests that the effects on the endometrium must have been more limited or focal."
Still, doctors might suggest to women who become pregnant after UAE that they undergo diagnostic hysteroscopy to ensure that they're not experiencing such complications. (A hysteroscopy is a minimally invasive uterine examination that involves the use of a fiber optic telescope.)
Another potential risk in performing embolization is to the myometrium, the lining of smooth muscle in the uterus. "It does seem possible that a uterus having substantial areas that underwent ischemic or hyaline degeneration may be weak and could potentially rupture," the researchers wrote. But Pron added that a number of women in their study had normal, and uneventful, vaginal deliveries after treatment, and any risks to the uterus are likely lower than those posed by invasive surgery.
An 'Extremely Promising' Treatment Approach
In conclusion, Pron and her associates determined that pregnancy is possible following uterine artery embolization for fibroids, and "most resulted in term deliveries and appropriately grown newborns." However, the investigators were quick to note that women who become pregnant following UAE should undergo "close monitoring" of their placenta, given the abnormalities that occurred in this study.
Nonetheless, "these outcomes do provide some hope to women who otherwise would have had a hysterectomy or are unsuitable for myomectomy [surgical removal of a fibroid tumor]," Pron and her team wrote.
Currently, myomectomy is the only treatment option for women with fibroids who intend to become pregnant later. Thus, future research should logically evaluate fertility outcomes in women who undergo UAE versus myomectomy, Pron stated. While results are still preliminary, embolization theoretically might wind up becoming the treatment of choice for these women.
"Everything about it is extremely promising," Pron said.
1. Pron G, Mocarski E, Bennett J, Vilos G, Common A, Vanderburgh L. Pregnancy after uterine artery embolization for leiomyomata: the Ontario multicenter trial. Obstet Gynecol 2005 Jan;105(1):67-76.
2. Society of Interventional Radiology. Uterine Fibroid Treatment Options.
3. Mayo Foundation for Medical Education and Research. Uterine Fibroids.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include coverage of health news for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
