The first moments after birth are monumental for your baby. As soon as your child leaves the womb, they need to 'switch over' to adjust to life independently from their mother's body, to begin functioning separately from the placenta, cord and uterus. As the baby is born, they leave an environment that has been completely life sustaining, providing oxygen, nutrition and warmth throughout the pregnancy, labour and birth.
At birth, the baby undergoes some amazing physiological adjustments to enable them to adapt to life alone in the 'outside world'. Such is the wonder of new life.
The major adaptations a newborn baby makes at birth involve:
Blood circulation
Starting to breathe air
Body temperature regulation
Blood circulation
At birth, the baby's unique intrauterine (or fetal) blood circulation changes over to a newborn's blood circulation (similar to an adult's). This physical adaptation means that the baby can start to absorb oxygen from their own lungs, rather than the placenta.
In the uterus, most of the baby's blood circulation bypasses their lungs. This happens through a natural opening in their heart (called the 'foramen ovale'). The opening is covered by a flap of muscle and allows the baby's blood to flow directly to and from their heart to the umbilical cord and the placenta for oxygen, instead of flowing to their lungs. This unique design allows the baby to obtain their oxygen supply (and excrete carbon dioxide), through their mother's blood and her lungs while in the womb.
At birth, the baby's first gasp of air (and to a certain extent the clamping of the cord) causes pressure changes in the baby's lungs. This pressure forces the flap of muscle in the baby's heart to close over the 'foramen ovale' opening. Once this happens, the blood flows away from the umbilical cord to the baby's lungs, causing the blood vessels in the cord to collapse.