Antenatal Corticosteroids

During a recent episode of the Healthful Woman podcast, “Antenatal Corticosteroids,” podcast host Dr. Nathan Fox and Dr. Celia Muoser discuss antenatal corticosteroids. These are short courses of steroids prescribed to pregnant women who are at risk of preterm delivery to help accelerate the baby’s lung development and improve outcomes for an early delivery. They explain why timing and patient selection are crucial for physicians in maximizing benefits while minimizing risks.

Why are Steroids Given During Pregnancy?

Steroids are given during pregnancy when there is a concern that a baby may be born prematurely. As Dr. Muoser explained, pregnancy care often means caring for “two patients,” both the mother and the baby. “We always have two patients, and we’re thinking about both of them.” One of the biggest challenges premature babies face is breathing. The lungs are the last organs to fully mature, and breathing issues often determine whether a newborn needs oxygen, ventilatory support, or intensive care.

Corticosteroids help prepare a baby’s lungs for life outside the womb. These medications act on lung cells called pneumocytes, improving lung maturity and helping the lungs exchange oxygen more effectively after birth. As a result, steroids reduce the risk of respiratory distress syndrome and can decrease how much breathing support a baby needs after delivery. 

When Is The Right Time to Receive Steroids During Pregnancy?

Steroids are not given to everyone during pregnancy. Instead, providers carefully assess who is most likely to benefit. Screening tools, such as cervical length measurements, can help identify patients who may be at risk for preterm delivery. While these tests cannot always prevent early birth, they can guide decisions about whether steroid treatment should be given in advance.

The benefit of steroids is highest when they are administered close to delivery, ideally within one week and up to two weeks before birth. Steroids are typically recommended between 24 weeks and 0 days and 33 weeks and 6 days of pregnancy. Before 24 weeks, the lungs may not be developed enough to respond to the medication, and historically, survival rates were very low at those earlier gestations. As care has evolved, providers now focus on giving steroids whenever there is a meaningful chance of early delivery within this gestational window.

About Steroids During Pregnancy

Steroids used in pregnancy are given as intramuscular injections. The most common medication is betamethasone, given in two doses 24 hours apart. After 48 hours, the course is considered complete. Another option, dexamethasone, is sometimes used and is given in doses 12 hours apart. Oral steroids are not effective for helping the baby’s lung development.

Short courses of steroids are considered safe for most patients. They do not have the same long-term side effects associated with prolonged steroid use, though they can temporarily raise blood sugar levels. Repeated or long-term use may affect fetal growth, which is why treatment is limited and carefully timed. In some cases, a single additional “rescue” course may be given if preterm delivery remains a concern weeks after the first treatment.

Ultimately, steroid treatment is about preparation. If there is a significant chance of early delivery, even at 24 or 25 weeks, giving steroids can help ensure the baby has the best possible support if birth happens sooner than planned.  Dr. Fox shared, “If there’s any significant chance that you’re going to deliver early, let’s just give them. And then if you do deliver the next two weeks, which isn’t great, but if you did, you got covered.”

Learn More

If you are interested in learning more about steroids given during pregnancy, listen to the full episode of the Healthful Woman podcast today. If you are seeking pregnancy care, schedule a consultation at MFM Associates in New York by completing the online contact form.

Maternal Fetal Medicine blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!