THURSDAY, Aug. 4 (HealthDay News) -- Women with the eating disorders anorexia and bulimia may take a bit longer to get pregnant than other women, a new study has found.

U.K. researchers asked 11,088 pregnant women to complete questionnaires at 12 and 18 weeks of gestation. Of those women, 171 (1.5 percent) had anorexia at some point in their lives, 199 (1.8 percent) had bulimia, and another 82 (0.7 percent) had experienced both conditions.

A larger proportion of the women with the eating disorders took more than six months to conceive compared to those with no history of eating disorders (39.5 percent vs 25 percent). However, women with eating disorders weren't more likely to take longer than 12 months to conceive, the investigators found.

Women with anorexia or bulimia were more than twice as likely to have received treatment or help to get pregnant, 6.2 percent vs. 2.7 percent.

The study also found that 41.5 percent of women with anorexia said their pregnancy was unplanned, compared with 28.6 percent of women in the general population. This suggests that women with anorexia may underestimate their chances of conceiving, the researchers said.

"This research highlights that there are risks to fertility associated with eating disorders. However, the high rates of unplanned pregnancies in women with a history of anorexia suggest that women may be underestimating their chances of conceiving," lead author Abigail Easter, from the Institute of Psychiatry at King's College London, said in a college news release.

"Women planning a pregnancy should ideally seek treatment for their eating disorder symptoms prior to conception and health professionals should be aware of eating disorders when assessing fertility and providing treatment for this," she added.

The study is slated for publication in BJOG: An International Journal of Obstetrics and Gynaecology.

More information

The U.S. National Institute of Mental Health has more about eating disorders.