Some important changes start taking place in a baby immediately after he or she comes through the birth canal and into the world. These changes will allow the newborn to survive outside the womb and adapt to their new environment.
The beginning of air breathed through the lungs marks a monumental first step. Inside the womb, the fetus gets fresh oxygen
into its blood from the mother’s blood, through the placenta. The fetus expels carbon dioxide through the placenta as well.
At birth, a baby’s lungs are filled with amniotic fluid, which filled the amniotic sac that protected him, though the lungs are not fully inflated. Once the baby comes out and the umbilical cord is cut, the baby takes his first breath.
Amniotic fluid now drains from the respiratory system and is absorbed into the body. Once the lungs inflate, they begin carrying oxygen into the newborn’s blood, and removing carbon dioxide when the baby exhales.
In the uterus, a developing fetus produces twice as much body heat as an adult. The baby’s excess heat is dissipated through the ongoing blood exchange that occurs in the placenta between mother and baby. After birth, the baby begins to lose body heat. Skin receptors then send messages to the brain that the baby is getting cold. The baby’s body now starts manufacturing its own heat by shivering, and by burning stores of a special brown fat that is found only in fetuses and newborns.
The kidneys begin producing urine 9 to 12 months into the pregnancy. Once a baby is born, he or she will urinate within the first 24 hours of autonomous life.
As for the gastrointestinal tract, the baby produces a dark brown waste product called meconium. This stool consists of amniotic fluid, mucus, fine body hairs, bile, and cells shed from the skin and the intestinal tract. Babies can pass stools before their arrival date; but sometimes, they pass them during the delivery, or in the first few days after they’re born.
A baby’s immune system begins to develop while he or she is still in the uterus, and it continues to improve through the first few years of life. While the uterus is a relatively sterile place, once the baby is born, the infant will immediately start being exposed to different types of bacteria.
Newborns carry in their blood some germ-fighting antibodies that their mother passed on to them. As they’re born vaginally, they also come into contact with the mother’s vaginal flora, which will colonize the baby’s sterile gut and begin to create the right environment for digestion of the food that will come next.
Breastfeeding a newborn is an important way to strengthen their young immune system. In addition to antibodies, breast milk contains immune factors, enzymes, and white blood cells. All these substances help to protect a baby against a number of diseases and infections, even after the infant has been weaned.
Breast milk can help prevent ear infections, diarrhea, pneumonia, and other diseases, by encouraging the growth of healthy bacteria in the intestinal tract of the breastfed baby; these bacteria aid the digestion of foods, the absorption of nutrients, and keep populations of harmful bacteria, viruses, and fungi in check.
There is no better way to start a baby on a healthy path toward immune health, and good health in general, than for mom to feed her infant exclusively breast milk for at least the first several months of the baby’s life, when the baby’s immune system is at its most vulnerable stage.
By Lisa Pecos