Fallopian tubes may appear to be normal and open, yet not function properly to allow the unification of egg and sperm or transport and nourish the embryo. For example, approximately 33-50% of all women after an ectopic (tubal) pregnancy will never again conceive despite the remaining tube being open! In such cases, the Fallopian tubes do not function biologically because of damage to the cellular lining which is crucial for proper function. Uterine and tubal infections, many times asymptomatic, are a possible cause of subtle tubal damage. Unfortunately, there is no accurate way to assess tubal function. Diagnostically, a high level of antibodies to chlamydia in a woman's blood may indicate a past tubal infection, which could only suggest a tubal cause of infertility. Patients having one tube blocked and a positive antichlaymidial antibody level should be considered as having a tubal problem.