As of 2015 in the United States, about 9.5 percent of all babies are born preterm, meaning they were born at less than 37 weeks gestation. We know that being born preterm can lead to multiple complications for a new baby, such as problems with breathing, eating, and maintaining normal blood sugar levels. This is why obstetric providers will often recommend injectable steroids if a mother is at risk of having a preterm birth.

Also known as antenatal steroids, these injections are usually given in one of two forms: betamethasone (more commonly used, and is a series of two injections 24 hours apart), or dexamethasone (four injections over 48 hours). We know that receiving these injections is one of the best things we can do to improve the outcomes of preterm babies.

Specifically, antenatal steroids have been shown to help with the following:

  • They lower the number of babies who are born with the breathing problem known as respiratory distress syndrome (RDS), and of those babies who do have RDS it is less severe.
  • They decrease the risk of internal bleeding in the brain known as intracranial hemorrhage, which if present can often lead to significant problems with development and intelligence.
  • They decrease the risk of the complication known as necrotizing enterocolitis, which is when too little blood flow goes to the intestines and they can become inflamed and die, sometimes leading to death in these fragile babies.
  • Lastly, premature babies who receive antenatal steroids dies less frequently than those whose mothers did not receive these injections.

Being able to prevent some or all of these complications is so important for these premature babies, which is why obstetric providers will routinely recommend antenatal steroids in women who are at risk of delivering at less than 34 weeks gestation. More recently, newer data has suggested that these benefits may also last in the late preterm period (35 to 36 weeks gestation), so women who may deliver in this timeframe may also receive these injections.

This intervention in preterm babies is so important that an organization known as The Joint Commission, whose purpose is to ensure hospitals are providing evidence-based care for their patients, routinely monitors hospitals in this country to make sure that women who should be receiving this medication actually do. With so many potential complications arising in our smallest babies, it is wonderful to know that an intervention such as antenatal steroids.


  • Antenatal steroids are a series of injections given to pregnant women who are at risk of delivering preterm.
  • These steroids have been shown to speed up the development of a premature baby’s lungs, brain, and digestive system, which helps to decrease the risk of some common complications of being born preterm.
  • All hospitals who care for preterm babies are monitored to make sure they are correctly administering these steroids to women who qualify for them, since they have such a big impact on babies who are delivered early.

Last reviewed by Diana Huang, MD, FACOG. Review Date: May 2020


  1. The American College of Obstetricians and Gynecologists. Committee Opinion #677: Antenatal corticosteroid therapy for fetal maturation. October 2016.
  2. March of Dimes. Preterm birth increases in the U.S. for the first time in eight years. 1 Nov 2016.


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