At birth the baby must start breathing, change its circulation and keep itself warm within minutes. Most newborns do this on their own, and a few need help.
First breaths
Lung fluid is squeezed out and absorbed, and the first breaths open the air sacs. Oxygen in the lungs relaxes the pulmonary vessels, so blood flows into the lungs.
Circulation changes
As lung pressure falls and body pressure rises, the foramen ovale closes and the ductus arteriosus begins to close over hours to days. Blood now passes through the lungs instead of bypassing them.
Keeping warm
Newborns lose heat fast through their large, wet skin surface. Dry the baby, use skin-to-skin contact and cover the head.
Feeding and glucose
Blood glucose dips in the first hours after the cord is cut. Early feeding helps keep it stable.
| Sign | Scores 0 | Scores 2 |
|---|---|---|
| Heart rate | Absent | 100 or more per minute |
| Breathing | Absent | Good, strong cry |
| Muscle tone | Limp | Active movement |
| Reflex response | None | Cries or pulls away |
| Color | Blue or pale all over | Pink all over |
At the bedside
Score the Apgar at 1 and 5 minutes; 7 to 10 is reassuring. A newborn who is not breathing or has a heart rate under 100 needs ventilation right away.
Related guides
Written by Making Synapses. Topic reference: OpenStax, Anatomy and Physiology 2e (no text adapted).