Late Preterm Steroids Are Here

By Eva Martin, MD of Elm Tree Medical, Inc.

Medical students on their OBGYN rotations have long memorized the corticosteroid rule: If delivery is imminent in the next week, before 34 weeks gestational age, give corticosteroids for lung maturity. Two doses, 24 hours apart have been shown to improve respiratory outcomes in strong, randomized clinical trials. However, what about the 70% of preterm deliveries that occur between 34 weeks and 36 weeks 6 days? Do these infants benefit from corticosteroids? The Society for Maternal Fetal Medicine is spreading the word about the new ALPS study on this very topic.

The Antenatal Late Preterm Steroids (ALPS) trial enrolled 2,831 women at 17 hospitals from 2010 to 2015. Patients who joined the trial had singleton pregnancies and presented to the hospital with preterm labor. The researchers were strict about their definition of preterm labor: cervix dilated at least 3 centimeters or 75% effaced, PPROM, or planned late preterm delivery for medical indications. Of course, all of the women were enrolled during the period in question: 34 weeks 0 days to 36 weeks 5 days (enough time to administer the 2 doses before 37 weeks). Women who were NOT included were those with unstable health status who would deliver within 12 hours, those who had previously received steroids earlier in the pregnancy, those with diabetes diagnosed before pregnancy, those with chorioamnionitis, and those with a contraindication to taking steroids. Enrolled mothers were randomly assigned to receive fake placebo shots or real steroid shots.

Who enrolled in this trial? 28% of enrollees were in preterm labor, 26% were undergoing late preterm delivery scheduled due to gestational hypertension or preeclampsia, and 22% had PPROM. Some women delivered before they were able to receive both doses of the drug. In the steroid group, 60% of the participants received both doses of the medication. Over 80% of women enrolled in the trial delivered preterm.

Did late preterm infants fare better if they received steroids? Yes! A baby's need for respiratory support within 3 days of birth was significantly lower if they received steroids. 14.4% of babies in the placebo group required respiratory support, and 11.6% of infants in the steroid group required this intervention. Babies who received steroids were also significantly less likely to suffer a severe respiratory complication, such as needing mechanical ventilation or continuous positive airway pressure or high flow nasal cannula for at least 12 continuous hours. Infants who received steroids did have an increased risk of hypoglycemia, 24% versus 14.9%. Other complications were the same in the two groups.

How did mothers do? After all, steroids are not without their side effects. Maternal outcomes including mode of delivery, chorioamnionitis, and endometritis were the same in the two groups.

Will this new study change practice? SMFM hopes so. Because of the large study size, the representative sample of women, and rigorous study methods, SMFM has endorsed new recommendations. Of course, they caution that doctors take care only to administer steroids to the indicated population of women anticipated to deliver in the late preterm period. They also recommend against using tocolysis to try to delay delivery until the full course of steroids is delivered.

We want to hear from you! Have you changed your practice to start giving steroids in the late preterm period?