ABSTRACT
A woman may experience anovulation, wherein eggs are not released from her ovaries. Her fallopian tubes may be blocked as a result of endometriosis (the presence of endometrial tissue in abnormal locations, including the fallopian tubes), in which case some of the lining of the uterus moves into the fallopian tubes. Moreover, sexually transmitted disease often leads to pelvic inflammatory disease, a major cause of occlusion of the fallopian tubes. Finally, immunologic problems may be the culprit, in which, for example, a woman produces antibodies against her husband's sperm.
