Updated

A woman's lifetime odds of undergoing surgery for a disorder known as pelvic organ prolapse may be higher than experts have believed - closer to 1 in 5, rather than 1 in 10 -- a new study suggests.

The condition occurs when weakened muscles and supporting tissue in the pelvis allow one or more organs, including the uterus, bladder or rectum, to move from their normal positions and protrude into the vagina.

Symptoms depend on the degree of organ displacement, or prolapse. Some women have no symptoms at all, while others have problems like pressure in the vagina and chronic pain in the lower abdomen or lower back.

More severe cases of pelvic organ prolapse may require surgery, but conservative treatments can also work. For women who are overweight, weight loss might help, while some women find symptom relief from exercises that strengthen the pelvic-floor muscles.

Removable devices called pessaries, which are inserted into the vagina to support the pelvic organs, are another treatment option.

When nonsurgical treatments fail, minimally invasive surgery to reconstruct supporting tissues in the pelvis and restore organs to their proper positions can be performed via small incisions in the abdomen or through the vaginal wall.

Past research has suggested that the average woman has an 11 percent to 12 percent chance of undergoing surgery for pelvic organ prolapse at some point in her life. However, that estimate is based on studies of women in U.S. managed-care health plans, a group that is not fully representative of the general population in the U.S., and may not apply to other countries.

In the new study, researchers found that among all women living in the state of Western Australia between 1981 and 2005, the average woman had a roughly 20 percent chance of having prolapse surgery by the age of 85.

The odds dipped slightly over time, from 21 percent between 1981 and 1995, to about 19 percent from 2001 to 2005.

"The rate suggests that the incidence of surgery for (pelvic organ prolapse) is common, and our estimates suggest that it may be even more common than previous reports have estimated," lead researcher Fiona Smith, of the University of Western Australia in Perth, told Reuters Health in an e-mail.

If that's the case, the findings underscore the need for greater awareness of pelvic organ prolapse, Smith said, noting that it tends to be something of an "un-discussed" gynecological disorder.

As it stands, there is only limited evidence for ways to help prevent prolapse, according to Smith.

But some of the established or suspected risk factors for the condition -- including obesity, smoking, chronic constipation and straining, and habitual heavy lifting -- are modifiable. Genes, which also seem to influence a woman's vulnerability to prolapse, are not.

Pregnancy and particularly vaginal birth are prime risk factors for pelvic organ prolapse as well.

But given the range of considerations that go into choosing between vaginal and cesarean delivery, no one is advising women to have a C-section just to lower the risk of prolapse.

Since a significant portion of women may eventually undergo surgery for prolapse, however, more research needs to go into understanding the causes of the disorder, and the best ways to prevent it, according to Smith and her colleagues.

For their study, reported in the journal Obstetrics & Gynecology, the researchers used a Western Australia database system set up for health research. Based on hospital data, 44,728 women in the state underwent first-time surgery for pelvic organ prolapse between 1981 and 2005.

Smith and her colleagues estimate that during the most recent five-year period -- 2001 through 2005 -- a woman's average lifetime risk of prolapse surgery was 19 percent.

That did represent a decline from the earlier years of the study period. In 1981, the researchers note, there were 3.5 first-time prolapse surgeries per 1,000 women for the year; in 2005, that figure was 2.6 procedures per 1,000 women.

The reasons for the decline are unknown, according to Smith's team. One possibility, they write, is that non-surgical treatment with pessaries has become more common. Another factor could be the falling birth rate and growing use of C-sections in Western Australia over the study period.

It is not clear how well the rates seen in Western Australia can be generalized to other countries.

But, Smith said, it's possible that rates would be comparable in countries with healthcare systems similar to Australia's.