Womb to outside life the baby goes on a 40 week journey from cell to human. Millions of cells make up the organs in side of us that help us function. Each person has a unique DNA strand that are made up of half of the mothers and half of the fathers DNA. The DNA tells the cells how to function and what to do. After you exit the womb you start of with a challenge, breathe or die. While in the womb the fetus float in the amniotic sac filled with amniotic fluid.
While inside the womb the fetus does not have to worry about breathing but when the exit the amniotic fluid stays in their lungs. Since the baby has yet to ever take a breath the adrenal glands, found at the top of the kidneys, sends adrenaline to help the body get a jump start so that all the organs will start working. Air gets pumped to the lungs going threw hundreds of air sacs called the alveoli. The first hour is when all the babies organs adapt to the world outside the womb.
When inside the mother the babies has never had to worry about breathing, bacteria, etc the amniotic sac protected and did everything for the fetus. Meconium is a tar like fluid that enters the baby when exiting the mother when they try to breathe. If it enters the air passage it can block air from getting out of the lungs and the baby could be in big danger. The fluid can be flushed out of the baby within days.
When in the womb the baby is use to a hundred degrees and while at home it is in the seventies. Since only being hours old the baby has to worry about hyperthermia. Since the baby is not fully developed yet their hypothalamus is not active and since it alerts the brain when you are too cold or hot the baby can not develop goose bumps. Thats where brown fat comes in to play. Brown fat