Serum prolactin and the suppression of lactation.

Bromocriptine (2 bromo-alpha-ergocryptine), stilboestrol, clomiphene citrate, testosterone propionate and a placebo were given to 75 postpartum women for the suppression of puerperal lactation. An additional 15 women who breast-fed their babies served as a control group. Blood samples were taken for the determination of serum prolactin levels by a specific homologous double antibody radioimmunoassay. Concurrently, the clinical effectiveness of the various treatments was assessed. High levels of prolactin were found at the time of delivery. Bromocriptine effectively reduced serum prolactin and prevented lactation; stilboestrol increased serum prolactin and partially suppressed lactation; clomiphene citrate and testosterone propionate both lowered serum prolactin levels and partially suppressed lactation. The placebo showed almost no effect on serum prolactin. It appeared that bromocriptine was the drug of choice in the suppression of puerperal lactation.