Increased serum prolactin levels during phenothiazine and butyrophenone treatment of six postpartum women

(1) Serum prolactin levels of six women, who developed psychoses during the postpartum period and were treated with neuroleptic drugs, were higher than those of a group of non-postpartum women of comparable age treated with similar doses of these drugs. (2) The magnitude of the neuroleptic-induced elevations in serum prolactin diminished with time during the postpartum period and returned to that found in non-parturient drug-treated females approximately 120 days postpartum. (3) A similar increased responsiveness of the hypothalamic-pituitary axis controlling prolactin secretion in postpartum females is manifested by the suckling response and increased prolactin response to thyrotrophin releasing hormone (TRH). The time course of normalization of these enhanced endocrine responses is roughly similar to that found for normalization of the prolactin response to neuroleptic drugs. A common mechanism may underlie each of these phenomena.