HARTFORD, Conn. - The health insurer Aetna is ending most coverage of hysterectomies performed with a once-popular device that has drawn warnings from federal regulators over a risk for spreading cancer.

The nation's third-largest health insurer said Tuesday that, as of May 15, it would curb coverage of power morcellation in hysterectomies or for removal of uterine fibroids "because the safety and efficacy of this approach has not been demonstrated."

Aetna Inc. will make exceptions for premenopausal women who want to maintain their fertility and for whom another treatment would not be effective. The company also will still cover the procedure in patients for whom the use of a more invasive surgical approach would be a life-threatening risk.

Hysterectomy - the surgical removal of the uterus - treats a variety of conditions, including severe endometriosis, chronic pelvic pain, uterine fibroids, and some cancers. Power morcellators are electric tissue-slicing devices that enable surgeons to shred and remove fibroids or the entire uterus through small abdominal incisions. Compared with standard procedures in which the whole abdomen is cut open, power morcellation reduces blood loss and recovery time.

The Food and Drug Administration warned last fall that the devices should not be used in most cases because they can spread a rare uterine cancer that standard preoperative tests cannot detect. Spreading the cancer is likely to worsen the patient's prognosis.

That's what happened in October 2013 to anesthesiologist Amy Reed. She and her husband, cardiac surgeon Hooman Noorchashm - who trained in Philadelphia and recently moved back to the area from Boston - launched a campaign calling for a ban on power morcellators. That led to the FDA warning and increasingly limited use and coverage of the device.

"Amy and I thank you all for acting in the best interest of public health and your company's good reputation," Noorchashm wrote to Aetna executives on Tuesday in an e-mail shared with the media.