What Are Antenatal Corticosteroids?

An antenatal medication is administered to a pregnant woman, often to affect the development of the fetus. When antenatal corticosteroids are used, they are intended to accelerate the development of the lungs of the fetus. Corticosteroids are synthetic versions of hormones that the body's adrenal gland naturally produces. The two corticosteroids that a doctor may prescribe for antenatal use are betamethasone and dexamethasone.

Babies that develop normally in the womb have a natural lubrication called surfactant that lines the lungs' air sacs. This substance allows for regular breathing. When the lungs do not develop normally, the baby tends to lack surfactant, which causes labored breathing and the need for respiratory equipment following birth.

Antenatal corticosteroids speed the development of the lungs so that they begin to produce surfactant naturally. This lessens the risk of respiratory distress syndrome (RDS) after birth. Betamethasone and other antenatal corticosteroids are typically given to the mother when she is expected to give birth within two days. They may also be used if the mother is already in preterm labor, between weeks 24 to 34 of her pregnancy.

The recommended dosing schedule is one dose of betamethasone given as an injection into a muscle. A second dose should follow this, about 24 hours later. Alternatively, those using dexamethasone might receive four injections into a muscle every 12 hours.

Steroid drugs are typically not administered to pregnant women unless the benefits outweigh the risks. Women who plan to receive an antenatal corticosteroid should discuss the potential risks with their doctors. This drug will cause the fetus' body movements and heart rate to slow, and if more than one dose is used, the potential for risks may increase. Infrequently, antenatal corticosteroids may cause the baby to develop hormone deficiencies following birth, however this condition may eventually resolve itself.

Infants who are born to women with diabetes, gestational or otherwise, might be at a higher risk for lung immaturity. These pregnancies should be closely monitored to evaluate the need for antenatal corticosteroids. In addition, these types of drugs can interfere with the mother's normal blood sugar levels. Diabetics may need to use a different dosage of insulin during the treatment, and they should also monitor their blood sugar levels carefully.

Before undergoing treatment with antenatal corticosteroids, women must disclose their other medical conditions, medications, and supplements. These drugs may be contraindicated for use by those with tuberculosis and other systemic infections, including fungal infections. Betamethasone and other corticosteroids may interact with other drugs, including nonsteroidal anti-inflammatory drugs (NSAIDs), blood thinners, and carbamazepine.