Prolactin measurement in the investigation of infertility in women with a normal menstrual cycle.

Basal serum prolactin concentrations were compared with mid-luteal serum progesterone concentrations and prospectively studied conception rates up to 12 months in women with otherwise unexplained infertility including a normal menstrual cycle. There were altogether 188 women with mean prolactin levels up to 3075 mU/l: 47 with prolactin up to 200 mU/l, 100 with prolactin 201-400 mU/l, 18 up to 600 mU/l, 16 up to 800 mU/l, and 7 greater than 800 mU/l. There were no significant differences in the mean progesterone values or chance of conception between any of the groups. The findings indicate that prolactin measurement is generally of no value in normally menstruating women, except possibly in the unusual event of evidence of persistent distinct luteal deficiency (not found in the present study).