Placental stress factors and maternal-fetal adaptive response: the corticotropin-releasing factor family.

The placenta and its accessory membranes amnion and chorion undertake the role of intermediary barriers and active messengers in the maternal-fetal dialog. They synthesize, metabolize, and serve as target to numerous hormones that regulate maternal and fetal physiology during pregnancy. Among these factors, corticotropin-releasing factor (CRF) has been one of the more investigated in the last decade. Increasing evidence indicates that in the event of acute or chronic metabolic, physical, or infectious stress, maternal or fetal physiologic and pathologic conditions may influence placental secretion of CRF. The current opinion is that the placenta actually takes part in a stress syndrome by releasing CRF, which may help to influence uterine perfusion, maternal metabolism, fluid balance, and possibly uterine contractility, thereby protecting the fetus from a hostile environment.