Breathing in the womb

Babies don’t breathe in the womb as we understand “breathing.” Instead, babies rely on their mother’s breathing to receive oxygen to their developing organs.

After nine months of growing inside of a mother’s body, a baby undergoes a complicated physical transition as they exit the womb. Research shows this transition is one of the most intricate things our body will ever do. While babies “practice” breathing in utero, their lungs aren’t used for breathing until they take their first breath outside the womb.

How do babies breathe in the womb?

The placenta and umbilical cord are organs that enable a developing baby to get everything it needs from its mother. This includes oxygen. Every breath that the mother takes brings oxygen into her bloodstream. The placenta carries oxygen to the placenta and then to the umbilical cord to the baby.

Fetal breathing practice

During weeks 10 and 11 of pregnancy, the developing fetus will start to inhale tiny bits of amniotic fluid. This “inhalation” is more like a swallowing movement. It helps the baby’s lungs as they begin to develop. By the 32nd week of pregnancy, a baby will begin to practice “breath-like” movements less like swallowing and involve compression and expanding the lungs.

Even though the baby’s lungs aren’t fully developed at 32 weeks, there is a good chance a baby born at this stage could survive outside the womb.

The breathing practice is a developmental milestone that sets the new baby up for success during their first cry. The baby’s lungs are considered mature at 36 weeks. By then a baby has had at least four weeks of breathing practice.

Breathing during delivery

Around the 40-week mark of pregnancy, the baby’s body is ready to make the transition out of the womb and into the world. During labor, the mother’s uterus will contract and retract. This causes her to feel intense sensations that signal the baby is coming. The contractions squeeze the baby, moving it into position to exit the birth canal. The contractions also serve to push amniotic fluid out of the baby’s lungs, preparing them to breathe.

The seal between the baby and the outside breaks when the mother’s water breaks. The baby may get exposure to oxygen during the birth process. But as long as the baby is still connected to its mother through the placenta via the umbilical cord, it’s not essential that the baby try to breathe yet.

Within a few moments after birth, the baby will take a sharp inhale and breathe for the first time on their own. This inflation of the lungs brings oxygen into the baby’s bloodstream without the mother’s help for the first time.

Breathing after birth

The baby’s new lungs are likely ready to carry them through life. But the respiratory system is not finished developing. Alveoli are tiny air sacs in the lungs that enable the exchange of oxygen in our bodies. They will continue to develop after birth.

At birth, it’s estimated most babies have between 20 to 50 million alveoli in their lungs. By the time a child turns 8 years of age, they will have up to 300 million. As the lungs grow, alveoli populate the new surface area of the lungs. This enables the lungs to support a growing human as they need increased amounts of oxygen.

The bones of the rib cage encircle our vital organs. As a baby grows, these bones will grow harder and the lungs will be more secure. This is an important part of respiratory development.

When we are first born, we are extremely vulnerable to “having the wind knocked out of us” because of the softness of our rib cages. The ribs will also rise in the chest to take an adult shape.

Sometimes a baby will involuntarily swallow or inhale parts of its first bowel movement during birth. This first bowel movement is called the meconium. When this happens, it’s essential to remove the baby from the womb quickly and get them medical attention. If the meconium isn’t removed it can pollute the baby’s delicate lungs.

What to avoid during pregnancy

One of the common complications of having a premature birth is that the baby’s lungs won’t be fully mature. Pneumonia and a condition called respiratory distress syndrome (RDS) can result. One way to avoid a premature birth is to pay careful attention to your diet and lifestyle choices during pregnancy.

The American Pregnancy Association recommends that pregnant women avoid:

  • raw meat
  • sushi
  • deli meat
  • uncooked eggs

All these foods contain harmful chemical agents or bacteria that shouldn’t pass on to a baby during development. Pregnant women should limit their intake of caffeine, and avoid alcoholic beverages. You should also avoid chemicals like salicylic acid, found in certain cosmetics and skin products.

The Food and Drug Administration (FDA) keeps an ongoing registry of medications that are safe to take during pregnancy. If one of the medications you have been prescribed is on the list of unsafe medications, speak to your doctor about the risks of continuing to use it.