Maternal prolactin secretion is phasic during induced term and post-term labor

Abstract

The biphasic secretion of maternal PRL is a fundamental characteristic of active term labor and occurs regardless of the method used to induce labor.

Maternal prolactin secretion during labor. The role of dopamine

“…Prolactin levels decreased until 1-2 h antepartum, then increased for about 3 h and then they finally decreased, starting at 2 h postpartum and reaching values lower than the basic at 6 h postpartum. These findings are generally in agreement with those reported in other studies (24)(25)(26)(27), with only minor differences regarding the exact time at which the extreme PRL values were recorded and the level was of statistical significance.…”

“…However, this pattern does not appear during labor. Instead, a multiphasic secretion pattern has been demonstrated, initially by Rigg and Yen (24), and this finding has been confirmed by other investigators since then (25–27).…”

“…There is a bulk of evidence suggesting that the upward trend in PRL levels during pregnancy is interrupted by the event of labor and it is replaced by a multiphasic pattern (20,(24)(25)(26)(27)31). It seems that labor includes or activates mechanisms that affect prolactin regulation; at the same time maternal prolactin seems to become rather unresponsive to usual stimuli, e.g.…”

“…Oxytocin seems to exercise prolactin-releasing activity (34). So, although labor induction does not appear to affect prolactin pattern (27), oxytocin was not administered in order to eliminate possible bias.…”