Antiprolactin drugs can induce erotic dreams. It is well-known that among many species of mammals, a lactating mother is not receptive to the male. In most tribal societies, love-making and breastfeeding are considered to be incompatible. These are the emergency hormones which give us the energy to protect ourselves by fighting or running away. If a female mammal is threatened by a predator while she is in labor, the release of adrenaline tends to stop the birth process, postponing it in order to give the mother the energy to fight or to escape.
Farmers know that it is impossible to milk a frightened cow.
The effects of adrenaline secretion are more complex during the birth process. During the very last contractions preceding birth, both a mother and her baby have a peak release of adrenaline hormones. One of the effects of this sudden adrenaline release is that the mother is alert when her baby is born. It is an advantage among mammals to have enough energy to protect the newborn baby. Another effect of this adrenaline release by the fetus is that the baby is alert at birth, with wide-open eyes and dilated pupils.