Nocturnal prolactin levels in infertility

Area of Science:

• Reproductive endocrinology
• Neuroendocrinology

Background:

• Serum prolactin naturally increases during sleep in women.
• Infertile women may present with normal daytime prolactin levels but abnormal nocturnal patterns.

Purpose of the Study:

• To investigate nocturnal serum prolactin concentrations in infertile women.
• To assess the impact of nocturnal hyperprolactinemia on luteal phase defects and treatment outcomes.

Main Methods:

• Nocturnal serum prolactin levels were measured every 30 minutes during the follicular and luteal phases in 13 infertile women.
• Bromocriptine treatment was administered to women with elevated nocturnal prolactin.
• Polytomography was used to evaluate for pituitary microadenomas.

Main Results:

• Seven of 13 infertile women exhibited increased nocturnal serum prolactin elevation compared to controls.
• Bromocriptine normalized nocturnal prolactin rise but did not consistently improve endometrial development.
• Five of seven women with nocturnal hyperprolactinemia showed findings consistent with pituitary microadenoma.

Conclusions:

• Infertile women can have nocturnal hyperprolactinemia despite normal daytime prolactin levels.
• Pituitary microadenomas may be associated with nocturnal hyperprolactinemia in infertile women.
• Treatment of nocturnal hyperprolactinemia with bromocriptine may not resolve luteal phase defects or improve fertility outcomes.