WASHINGTON (AP) — A product commonly used in surgery to treat pelvic collapse and other women's health problems causes far more complications than previously thought and is likely exposing patients to unnecessary risks, according to U.S. health officials.

The Food and Drug Administration said that women who have a surgical mesh implanted to support their reproductive organs are at greater risk of pain, bleeding and infection than women who have traditional surgery with stitches.

“The added benefit of using the mesh is not evident but there certainly appears to be an added risk,” said Dr. William Maisel, FDA's chief scientist and deputy director of the center for devices.

More than a half-million women undergo surgery for so-called pelvic prolapse and incontinence each year, though not all procedures involve mesh. About 75,000 women had prolapse surgery with mesh inserted through the vagina last year and more than 200,000 women had the procedure for incontinence. A less common procedure inserts the mesh through the abdomen and the FDA said there are significantly fewer complications with that technique.

Between 2008 and 2010, the agency received more than 1,500 reports of complications from women undergoing vaginal prolapse surgery with mesh, up 500 percent from the prior three years. There were fewer complications among incontinence patients.

The warning applies only to mesh for prolapsed but the agency is also reviewing its use for incontinence, though side-effects have not been as frequent. Doctors who perform the procedures say incontinence surgery uses less mesh, possibly resulting in fewer complications.

In a rare mea culpa, FDA scientists said a 2008 public notice from the agency that called the problems “rare” was mistaken. After reviewing the medical literature over the last 15 years, the FDA now estimates the most common problems occur in 10 percent of women within a year of surgery. These patients often undergo multiple surgeries to remove the mesh.

Manufactured by a half-dozen companies, the plastic mesh is used to strengthen the pelvic wall in cases of stress urinary incontinence and pelvic organ prolapse in which the bladder or other reproductive organs slip down into the vagina. The mesh is often inserted through the vagina, using a small surgical incision. Many doctors prefer this method to abdominal placement which requires a larger incision.

Despite the high rate of injury, FDA's top device scientist said the government would not withdraw approval for the product because certain patients may still benefit.

The FDA will ask panelists at September's meeting whether pelvic surgical mesh should be reclassified as a high-risk device.

Surgeons began using it to repair hernias in the 1950s and over the next 40 years they adapted the technique for women's health conditions. The FDA cleared the first mesh for prolapse in 2002 but since it was similar to devices that had been used for decades, it did not have to undergo human testing.

Manufacturers of pelvic mesh include Boston Scientific Corp.,  Johnson & Johnson, Covidien, CR Bard Inc. and American Medical Systems.