Premature Baby Lung Development

A baby needs a fully developed set of lungs in order to breathe well on her own and to provide enough oxygen for her body’s tissues. A premature baby’s lungs may be underdeveloped, causing difficulty with breathing and putting the baby at risk of developing complications. Extra care must be given to the baby born prematurely to sustain her with enough oxygen for her body, while her lungs continue to develop as she grows.

Fetal Development

Babies develop lungs before they are born, but while still in the womb they do not breathe air. The lungs begin as tiny buds that lengthen into the branches of the airways by 16 weeks gestation. By 28 weeks gestation, tiny sacs known as alveoli are developing and surfactant is excreted. Surfactant lubricates the lung tissue and promotes elasticity for better oxygen exchange after delivery.


mother holding newborn infant in hospital

Newborn Baby Breathing Problems

Learn More

As soon as a baby is born, he begins to breathe the air around him. The air travels down into the lungs, where it is dispersed into the alveoli, which are located at the outer edges of the lung tissue. They are surrounded by blood vessels. The membranes of the alveoli are extremely thin to allow oxygen particles to transfer into the blood vessels. Alternatively, carbon dioxide in the bloodstream crosses back into the alveoli where it is sent out of the body when a baby exhales.


Because surfactant production occurs later in pregnancy, babies that are born prematurely may have less, causing breathing difficulty after birth. Treatment of this condition involves helping a baby to breathe using oxygen and a ventilator. A physician may give artificial surfactant directly into the lungs after birth to help with breathing as a baby continues to grow. Artificial surfactant is an important treatment, because if a baby is born before her lungs have fully developed, she will not continue to produce surfactant after birth.


mother holding newborn infant in hospital

How Do Babies Breathe in the Womb?

Learn More

Many premature babies receive oxygen through a ventilator, which delivers a set number of breaths each minute to help with breathing. Long-term ventilator use while a baby’s lungs are developing can cause damage to the fragile tissues, resulting in scarring and decreased elasticity. This condition is known as bronchopulmonary dysplasia (BPD), and can lead to long-term conditions such as increased susceptibility to infections or the development of asthma.


According to the American Pregnancy Association, most babies have mature lung tissue by approximately 36 weeks gestation. If a mother goes into preterm labor before 36 weeks, there is a risk of having a baby with immature lung tissue. Some physicians give mothers a steroid injection, which can help promote lung development in a fetus before birth. Steroid injections are typically only given when delivery of a preterm baby is imminent.