Prolactin in the evaluation of luteal phase in infertility.

Hyperprolactinemia was detected in 15 of 130 infertile patients (11.5%) with regular menstrual cycles and no galactorrhea who underwent luteal phase evaluation by basal body temperature (BBT), plasma estradiol (E2), and progesterone (P) determination, and endometrial biopsy (repeated in a later cycle when the first was defective). Luteal phase length and plasma levels of P and E2 were similar in the hyperprolactinemic and normoprolactinemic patients. Moreover, a significantly higher incidence of inadequate luteal phase, histologically documented, was found in the normoprolactinemic group. It is concluded that the usefulness of plasma prolactin (PRL) determination in the evaluation of luteal function in infertility is scanty and that most histologically documented cases of luteal phase defects occur with euprolactinemia.