For decades, OBGYNs have used a type of medicine called steroids to help fetus's lungs mature if there was a risk of preterm birth. For example, imagine a mother comes to the hospital with painful contractions at 30 weeks pregnant, and she is diagnosed with preterm labor. Because there is a risk that the infant might be born preterm, the baby's lungs won't have enough time to mature before birth. If the lungs are not mature, the baby may suffer from respiratory distress syndrome and need treatments like supplemental oxygen or invasive ventilatory support. A steroid called betamethasone, given in two shots one day apart, can help to progress lung maturity. Historically, OBGYNs have only given betamethasone before 34 weeks of pregnancy because initial studies in the 1970s showed it was not helpful after 34 weeks.
Dr. Cynthia Gyamfi-Bannerman of Columbia University in New York, recently reported on the results of an exciting new study she conducted to test whether giving steroids after 34 weeks would benefit infant's lungs. She and her group of researchers enrolled 2,831 pregnant women at 17 different hospitals to participate in the trial. All of the women were at high risk of delivering preterm, which is before 37 weeks of pregnancy, and were between 34 weeks and 36 weeks 5 days pregnant (enough time to get the two shots before hitting the 37 weeks mark).
Half of the women received two fake shots (placebo) and half received two steroid shots. After the infants were born, the researchers carefully recorded whether the infants had any breathing-related treatments for the first 3 days of life, such as a cannula with extra oxygen in the nose for at least 2 hours. The researchers found that steroids reduced the need for respiratory treatments by 20% compared with the placebo shots. 11.6% of infants who received steroids needed treatments in the first three days, and 14.4% of infants who received the placebo shots needed treatments. They also needed fewer intensive treatment including resuscitation at birth and surfactant (medicine to open the lungs to air). Severe complications related to breathing problems were also lower for infants receiving steroids.
The two groups did have the same rates of diagnosis of respiratory distress syndrome, apnea (breaks in breathing), and pneumonia. However, infants who received steroids had less transient tachypnea of the newborn (breathing fast) and less bronchopulmonary dysplasia.
There was one medication side effect that was more common in babies who received steroids- low blood sugar. This is a known possible side effect of steroids, and all the babies were successfully treated without any further complications.
Overall, this is an extremely interesting new study that challenges a clinical practice that has been around for decades. We will have to wait and see if the large OBGYN physician groups like SMFM and ACOG decide to change their current recommendations given the new data.