Infertility in females can be associated with amenorrhea / oligomenorrhea or with apparently normal menstruation. The latter can occur due to luteal phase deficiency which may involve abnormal follicular development, ovulation or luteal function. A variety of clinical causes identified include use of certain medications, systemic disease states and endocrine abnormalities. A couple is considered infertile if they fail to conceive after six months of unprotected intercourse.