What are antenatal corticosteroids?

Preterm labor is labor that happens too early, before 37 weeks of pregnancy. If you have preterm labor, your health care provider may recommend antenatal corticosteroids to help speed up your baby’s lung development and reduce the chances of some complications.

How do antenatal corticosteroids work?

There are two types of corticosteroids that may be used if you’re in preterm labor, betamethasone and dexamethasone. Both of these steroids help your baby’s lungs produce surfactant. Surfactant is a protein that helps keep the small air sacs in the lungs from collapsing. When a baby is born full-term, her lungs produce surfactant naturally. But babies born premature do not produce enough surfactant, and that means the air sacs in the lungs do not expand the way they should. This results in premature babies having breathing difficulties.

When should you get antenatal corticosteroids?

The American College of Obstetrics and Gynecology (ACOG) recommends a single course of corticosteroids for pregnant women who are at-risk of premature birth within the next 7 days. This includes women whose membranes have ruptured and women pregnant with twins or other multiples. If you’re pregnant and at-risk for giving birth early, talk to your health care provider and discuss the best treatment options for your specific situation.

Are antenatal corticosteroids effective?

If you’re in preterm labor and you receive antenatal corticosteroids, your baby’s chances of having certain health problems after birth are reduced, including:

• Respiratory Distress syndrome (RDS). This is a breathing problem most common in babies born before 34 weeks of pregnancy. Babies with RDS don’t have enough surfactant and it results in breathing problems.
• Intraventricular hemorrhage (IVH). This is bleeding in the brain. It usually happens near the ventricles in the center of the brain. A ventricles is a space in the brain that’s filled with fluid.
• Necrotizing enterocoloitis (NEC). This is a problem with a baby’s intestines. It can cause feeding problems, a swollen belly and diarrhea. It sometimes happens 2 to 3 weeks after a premature birth.

Are there side effects?

Possible side effects of medicines like betamethasone and dexamethasone for mom may include fluid build-up in the body and increased blood pressure. There are no side effects for your baby.

If you’re at risk of giving birth early, talk to your provider about antenatal corticosteroids and how they may be able to help your baby. You can learn more about other treatments for preterm labor on our website. And all pregnant women should learn the signs and symptoms of preterm labor. If you have even one sign or symptom, call your health care provider. If you’re having preterm labor, getting help quickly is the best thing to do.

Have questions? Email us at AskUs@marchofdimes.org.