Then comes birth.
Ingrid's operatic entrance to the world
Air on the face makes the baby gasp, inflating the lungs with atmosphere for the first time. That's when the placenta does its trust fall. It unclenches its grip on the uterine wall, abruptly severing the lifeline that up to this point has been the baby's sole support. That is the ultimate moment of truth, like the freefall you feel when the computer freezes on your term project and you have to hit ctrl alt delete. Or that moment at night when you turn off the engine of a Volkswagen van halfway through Canada. Not sure how much you're gonna lose. Not sure if it's gonna start up again.
When all goes well, the baby metabolic motor jerks into autonomous mode and from that instant on relies on its own lungs and stomach to sustain life. Interestingly, the placenta often hangs on until the baby is latched on to its mother's breast. That first nursing stimulates the mother and signals the baby and uterus that the Hail Mary pass from womb to boob has been completed. (UNICEF's "newborn crawl" video on Youtube gives a lot more detail of all the things that go on to get the baby where it needs to be including the fact that the mother's nipples smell like amniotic fluid to draw the baby to them and the baby's crawling across the stomach causes the uterus to contract ... it's a miracle any of us are alive).
I wonder if the detachment is caused by the placenta letting go or the uterine wall shaking it loose. Is it the baby's or the mother's side of the handshake that lets go?
All babies lose weight during the first week while their system warms up (a big part of that is waiting for the right bacteria to populate their sterile bowels so they can digest effectively) and mom's milk supply comes in. This is why, even under the best of circumstances the baby fattens back to its birth weight by two weeks. Pretty cool.
All this going on behind those shiny black eyes. All this hereditary wisdom maximizing the likelihood of us loving and taking care of him. We're all just trying to survive.
(here are some pictures from Punjab's first week)