> "“Have you ever wondered,” one visiting professor asked, “why a colt doesn’t get up and gallop around inside the mare?” After all, a horse only minutes old is already able to hobble around the barnyard. The answer, as Mellor reported in an influential review published in 2005, is that biochemicals produced by the placenta and fetus have a sedating and even an anesthetizing effect on the fetus (both equine and human). This fetal cocktail includes adenosine, which suppresses brain activity; pregnanolone, which relieves pain; and prostaglandin D2, which induces sleep — “pretty potent stuff,” he says.
Combined with the warmth and buoyancy of the womb, this brew lulls the fetus into a near-continuous slumber, rendering it effectively unconscious no matter what the state of its anatomy."
See: http://www.nytimes.com/2008/02/10/magazine/10Fetal-t.html
> "“Have you ever wondered,” one visiting professor asked, “why a colt doesn’t get up and gallop around inside the mare?” After all, a horse only minutes old is already able to hobble around the barnyard. The answer, as Mellor reported in an influential review published in 2005, is that biochemicals produced by the placenta and fetus have a sedating and even an anesthetizing effect on the fetus (both equine and human). This fetal cocktail includes adenosine, which suppresses brain activity; pregnanolone, which relieves pain; and prostaglandin D2, which induces sleep — “pretty potent stuff,” he says.
Combined with the warmth and buoyancy of the womb, this brew lulls the fetus into a near-continuous slumber, rendering it effectively unconscious no matter what the state of its anatomy."