DURHAM, N.C. - In a finding that confirms what many obstetricians and gynecologists suspected, Duke University researchers report that younger women who undergo hysterectomies face a nearly two-fold increased risk for developing menopause early.
The study, published in the December issue of the journal Obstetrics & Gynecology, is the largest analysis to track over time the actual hormonal impact of woman who had hysterectomies and compare them to women whose uteruses remained intact.
"Hysterectomy is a common treatment for many conditions, including fibroids and excessive bleeding," said Patricia G. Moorman, PhD., MSPH, an associate professor in the Department of Community and Family Medicine at Duke University and lead author of the study. "Most women are very satisfied with the results of a hysterectomy. But this is a potential risk of the surgery that should be considered along with the benefit."
Up to 600,000 women in the United States undergo hysterectomy each year, but the long-term consequences of the procedure have not been well documented. Studies have been small, or relied on the recollections of women about the onset of menopause.
The Duke team enrolled nearly 900 women ages 30 to 47 at two hospitals in Durham, N.C. -- Duke University Medical Center and Durham Regional Hospital - and followed up with blood tests and questionnaires for five years. Half the women, 465, were healthy controls who had no surgery, while 406 women underwent hysterectomies that spared at least one ovary.
Preserving the ovaries while removing the uterus is a strategy designed to allow a woman's hormone production to continue, which has health benefits. Moorman said doctors have long known that early menopause ¬- either from surgery or from other factors that halt egg production - can increase a woman's risk of osteoporosis, heart disease and other ailments.
Yet despite preserving the ovaries, the Duke team found that 14.8 percent of women in the study who had hysterectomies experienced menopause over the course of the study, compared to 8 percent of women who had no surgery. The risk for menopause was highest among women who had one ovary removed along with their uterus, but it remained elevated even when both ovaries stayed in place. The Duke team's analysis estimated that menopause occurred approximately two years earlier in the women who underwent hysterectomy.
Moorman said it's unknown what triggers the ovaries of some women to shut down after a hysterectomy.
"Some have hypothesized that surgery disrupts the blood flow to the ovaries, so the surgery leads to early ovarian failure," she said. "Others have speculated it's not the surgery, but the underlying condition preceding the surgery that causes it. Right now, it's unresolved."
Regardless of the cause, Moorman said the Duke finding provides women and their doctors with concrete information about a potential risk.
"This could potentially change practice because women who are considering hysterectomy for fibroids or other problems may want to explore other treatment options for their condition if they know they may go through menopause earlier," Moorman said.
In addition to Moorman, study authors include Evan R. Myers; Joellen M. Schildkraut; Edwin S. Iversen; Frances Wang; and Nicolette Warren.
The study was funded with grants from the National Institute on Aging and the National Center for Research Resources. The authors reported no financial conflicts of interest.