Serum prolactin response to embryo transfer during human in vitro fertilization and embryo transfer

Serum prolactin (PRL) concentrations around the time of embryo transfer (ET) have not been studied, despite the fact that transient hyperprolactinemia regularly occurs in response to laparoscopy for oocyte recovery and ET itself may be stressful enough to induce a PRL rise. Hyperprolactinemia might compromise luteal support for implantation and contribute to the limited success of ET. We measured serum PRL concentrations in 10 normoprolactinemic women immediately before, during, and after ET and compared the PRL response around ET to that induced by laparoscopy as a measure of the competency of the stress-prolactin axis. Nine of ten patients demonstrated a significant PRL response to surgery. The mean (+/- SEM) intraoperative PRL concentration (124.0 +/- 19.6 ng/ml) was significantly higher than the preoperative level (12.3 +/- 2.4 ng/ml) (P less than 0.01). Three hours after surgery PRL levels had decreased (44.8 +/- 11.5 ng/ml) but remained above baseline. All subjects were normoprolactinemic 48 hr after laparoscopy. Serum PRL concentration did not change significantly in response to ET, with levels of 10.4 +/- 1.7, 12.4 +/- 1.1, and 10.6 +/- 1.8 ng/ml immediately before, during, and 3 hr after ET, respectively. While laparoscopy for in vitro fertilization--embryo transfer commonly induces hyperprolactinemia, the PRL rise is transient, with no carryover to the time of ET. Embryo transfer itself does not induce a significant PRL rise.