What Is Fetal Lung Maturity?

What is fetal lung maturity? Basically, it's the ability of babies to breathe normally once they're born. In order for this to take place, their lungs must develop adequately within the mother's womb during gestation.
What Is Fetal Lung Maturity?

Last update: 13 May, 2019

Fetal lung maturity is one of the most important aspects during the process of a baby’s development. This is especially true for babies that present certain issues or are born prematurely.

In practice, when the risk of premature birth exists, doctors generally prescribe a special medication to mothers. This medication accelerates the maturity process. 

Below, we’ll take a look at the essential aspects of this issue, which is so relevant to the health of our children.

The importance of fetal lung maturity

The development of fetal lung maturity is one of the most important factors in enabling babies to breathe normally once they leave their mother’s womb.

To facilitate vital functions, their little lungs must be perfectly developed once pregnancy reaches full term. This includes the pulmonary alveoli and bronchi, as well as a substance known as surfactant. This is something that all human beings have.

Pulmonary surfactant is essential in the proper functioning of the lungs. Without it, lungs quickly collapse. The reason is that this substance coats the alveoli and produces a sort of bubble that allows the lungs to stay open. Thus, air can flow freely.

Fetal lung maturity in premature babies

Over the duration of pregnancy, the fetus develops progressively. This includes, of course, the development of the baby’s internal organs. In fact, the organs develop during the first three months of gestation.

External care is extremely necessary during this period in order for development to occur properly. Any medication, bacteria or illness trigger diverse types of malformations.

What Is Fetal Lung Maturity?

While a baby’s internal organs develop completely during the first three months of life,  they must still mature. This maturation occurs during the second and third trimester, and is fundamental. It’s what allows newborns to live fully in the outside world.

As for the lungs, they develop during the first weeks of pregnancy, but don’t mature completely until after week 34. When babies are born, their lungs should expand to allow for the exchange of blood and air. Fetuses acquire this ability at about 34 weeks.

When birth takes place before 37 weeks of gestation, a variety of complications can occur. Among the possible complications are those having to do with the lungs. One of the most frequent problems is known as respiratory distress syndrome (RDS).

“The development of fetal lung maturity is one of the most important factors in enabling babies to breathe normally once they leave their mother’s womb”

Is it possible to help a baby’s lungs develop?

It is possible to accelerate the maturation of a fetus’s lungs. Fortunately, science has made giant leaps in this area. Thanks to these advances, the lives of thousands of babies around the world have been saved.

There are several pharmaceuticals that can aid in the maturation process of babies’ lungs. Thus, the process is known as pharmaceutical lung maturation.

The application of this treatment is very simple. A doctor administers steroids to the mother through intramuscular injections. Treatment consists of 2 injections, 24 hours apart from one another.

Once both doses are applied, fetal lung maturity will take place. If an emergency premature C-section becomes necessary, the doctor will administer at least one dose before going through with the procedure.

General criteria for the treatment of fetal lung maturity

There are general criteria that indicate to the doctor in charge whether or not treatment for fetal lung maturity is necessary. In this sense, doctors take into account a baby’s gestational age and whether or not there are any counter-indications for the mother .

Women who suffer certain complications during pregnancy shouldn’t receive lung maturation treatment. As treatment can seriously affect the mother’s health in these cases, constant fetal monitoring must replace steroid injections.

For example, pharmaceutical lung maturation is especially dangerous for women with diabetes that isn’t under control. The same is true for women who suffer from arterial hypertension.

In conclusion, even though fetal lung maturity is very important, there are occasions when a baby must be extracted prematurely. In most of these cases, doctors can prescribe steroid treatment injections to accelerate lung maturation and save the baby’s life.


This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.