Premenopausal women who have both ovaries removed during a hysterectomy are at higher risk of  heart disease and other cancers, researchers reported.

Both ovaries may be taken out by a surgeon treating a benign disease of the uterus as a protection against ovarian cancer.

The study, “Removal of all ovarian tissue versus conserving ovarian tissue at time of hysterectomy in premenopausal patients with benign disease: study using routine data and data linkage,” was published in the journal BMJ.

The study was the largest of its kind on this issue and covered 10 years of data. Led by Richard Lilford, a professor of obstetrics and gynecology at the University of Warwick medical school, in England, the researchers compared women whose ovaries were removed as treatment for a benign disease and women who had only one or none removed.

The study included 113,679 women, ages 35-45 years, who had a hysterectomy between April 2004 and March 2014. A third had both ovaries removed.

Findings revealed that women who had one or no ovaries removed were subsequently less likely to develop coronary artery disease (ischaemic heart disease) or a cancer, compared to those who had both ovaries removed.

Fewer women who had one or no ovaries removed died during the study period, compared to those who had both ovaries removed (0.6% vs. 1.01%).

“The combination of biological plausibility and the massive ‘effect size’ make a compelling case that women can be advised that their risk of ovarian cancer is greatly reduced by surgical removal of both ovaries,” Lilford said in a press release. “However, the lifetime risk of developing ovarian cancer is one in 52 in the UK, and the removal of a metabolically active organ such as the ovary may have harmful effects in the long term.”

Researchers also found that 40 percent of women with no specific risk factors for ovarian cancer had their ovaries removed in the 35-45 age group.

The authors believe their findings suggest that the risks associated with the procedure in premenopausal women need to be better considered.

“Although removal of both ovaries protects against subsequent development of ovarian cancer, premenopausal women should be advised that this benefit comes at the cost of an increased risk of cardiovascular disease and of other (more prevalent) cancers and higher overall mortality,” the study concluded.