Celiac disease is a fairly common but often undiagnosed autoimmune disorder.
Women with this disease have an allergic reaction to gluten, which is found in most wheat products, rye, barley, oats, and other foods. Celiac disease affects fertility in a roundabout way, by making it difficult for sufferers to properly absorb food. Unable to receive enough nutrients and vitamins, the hormones that stimulate the ovaries can be suppressed, preventing ovulation. Treatment for celiac disease is completely dietary: sufferers must avoid gluten and learn to balance nutrients properly. Once women with celiac disease follow a gluten-free diet, all symptoms of the disease will reverse, including problems with ovulation and conception.
For more fertility tips, check out Conceive's book, Fertility Facts: Hundreds of Tips for Getting Pregnant.