Serum prolactin and estrogen pattern in human gestation

In a group of 17 normal women serum levels of fetoplacental hormones (estradiol, progesterone and human placental lactogen) and of prolactin were measured serially from the 6th week to the end of pregnancy. The levels of these hormones increased gradually until the term. On the basis of these observations it may be concluded that no statistical evidence may be found on any direct effect of estradiol on prolactin release. These results seem to confirm some earlier data that estrogens may be less marked stimulators of prolactin secretion in man than in animals.