Observing that women with the most severe form of endometriosis happen to be unusually attractive, researchers in Italy speculate that the qualities that led to the women's good looks also predisposed them to the painful gynecological condition.

In the study, independent observers rated 31 percent of women with severe endometriosis as attractive or very attractive, while just 8 percent of women with milder endometriosis, and 9 percent of women without the condition were rated that highly.
"Several researchers believe that a general phenotype exists which is associated with the disease," said study researcher Dr. Paolo Vercellini, an obstetrician and gynecologist at Universita degli Studi in Milan.

It may be that a more feminine body type is the result of the same physical characteristics that predispose women to develop severe endometriosis, Vercellini said.

Female attractiveness is linked with higher estrogen levels, and it's possible that the hormone "might favor the development of aggressive and infiltrating endometriotic lesions, particularly in the most feminine subjects," the researchers wrote in their study.

The study was published online Sept. 17 in the journal Fertility and Sterility.

A more feminine silhouette
In endometriosis, cells that normally line the uterus leave the organ and become deposited in other sites within the body, such as on the ovaries, rectum, bladder or pelvic area. These deposits respond the same way as normal uterine cells do to the hormone changes that occur over a woman's monthly cycle — they thicken, and then shrink — which can cause pain in the pelvic region, and bleeding.

Endometriosis is thought to affect 5 to 10 percent of women. The severe form, called rectovaginal endometriosis, is much less common than milder forms, Vercellini said.

In the new study, researchers looked at 100 women with rectovaginal endometriosis, 100 women with less severe endometriosis, and 100 women without endometriosis who were undergoing gynecologic surgery for other reasons. Most of the women in the studies were in their late 20s or early 30s.

Two male and two female doctors who did not know the women's diagnoses met with each woman for a few minutes, and rated her overall attractiveness on a 5-point scale.

Other researchers took measurements of the women, and calculated their body mass indexes, their waist-to-hip ratios, and their "breast-to-underbreast" ratio — a measure of breast size.

Results showed that the women with severe endometriosis had lower body mass indexes, and larger breasts, than those without the disease.