High levels of proclactine is considered as the most frequent cause of anovulatory sterility, although spontaneous pregnancy may occur occasionally. In young women, hyperprolactinemia is probably one of the most common endocrine disorders related to pituitary function.
Clinically significant elevation of PRL levels may cause infertility in several different ways. First, prolactin may stop a woman from ovulating. Without ovulation it is not possible to concieve a child. If this occurs, a woman’s menstrual cycles will stop.
In less severe cases, high prolactin levels may only disrupt ovulation once in a while. This would result in intermittent ovulation or ovulation that takes a long time to occur. Women in this category may experience infrequent or irregular periods.
Women with the mildest cases involving high prolactin levels may ovulate regularly but not produce enough of the hormone progesterone after ovulation. This is known as a luteal phase (the latter phase of the menstrual cycle which begins with the formation of the corpus luteum- a temporary endocrine structure in female ovaries that is involved in the production of relatively high levels of progesterone) defect. Deficiency in the amount of progesterone produced after ovulation may result in a uterine lining that is less able to have an embryo implant. Some women with this problem may see their period come a short time after ovulation.
There is no study which can prove the association of male infertility with high levels of prolactin. The only thing that is known, is that hyperpolactinemia is associated with lower sex drive.