Women with anorexia are more likely to have unplanned pregnancies and abortions than those without the eating disorder, according to a new study.

The results, based on a survey of women in Norway, show 50 percent of anorexic women reported having unplanned pregnancies compared with 18.9 percent of those without anorexia. And 24.2 percent of those with anorexia said they had had an abortion compared with 14.6 percent of women who didn't have the disorder.

The higher rate of unplanned pregnancies among anorexic women may be driven by a mistaken belief that they can't get pregnant because they are either not having menstrual periods at all or are having irregular periods, said study researcher Cynthia M. Bulik, director of the University of North Carolina Eating Disorders Program.

"Just because you're not menstruating, or because you're menstruating irregularly, doesn't mean you're not at risk for becoming pregnant, Bulik said."

Physicians and other health care providers need to be aware of this as well, Bulik said. Doctors who treat women and adolescent girls, in particular, "need to make sure that they have the conversation about sexuality and contraception as clearly with patients with anorexia as they do with all other girls and women."

In addition, health care providers who take care of pregnant women need to know if their patients have an eating disorder in order to provide appropriate care . Screening for eating disorders during prenatal visits is an excellent first step, Bulik said.

The participants were part of the Norwegian Mother and Child Cohort Study, which involved 62,060 women, 62 of which reported having anorexia.

Those women with anorexia were also more likely to give birth earlier. The average age of the mothers at delivery was 26.2 years in women with anorexia, compared with 29.9 years for those without anorexia.

The study is published in the November issue of the journal Obstetrics & Gynecology.