Antenatal Corticosteroid Use at 34-36 6/7 weeks

Summary: In singletons between 34 0/7 and 36 5/7 weeks with a high likelihood of delivery within the next week who have not previously received antenatal corticosteroids, a single course of corticosteroids significantly reduces the risk of respiratory morbidities, and does not increase the risk of infectious complications.  There is a small increased risk for transient neonatal hypoglycemia associated with this therapy, which was of limited clinical significance in the trial.  

We encourage providers considering this therapy for their patients to consider close adherence to the study protocol outlined below. The value of betamethasone for indications not addressed in this trial are unknown, e.g. giving a repeat course between 34-37 weeks

In January 2016, the NEJM published the findings of the Antenatal Betamethasone for Women at Risk for Late Preterm Delivery (ALPS) trial (PMID: 26842679), a large multicenter RCT of betamethasone versus identical placebo for fetuses at risk for late preterm delivery.

Inclusion Criteria:

• Singleton pregnancy 34 0/7 weeks to 36 5/7 weeks
• High likelihood of delivery by 36 6/7 weeks (preterm labor with either 3 cm dilation or 75% effacement; PPROM; high probability of induction or cesarean delivery within 1 week of therapy, as determined by an obstetrician)

Exclusion Criteria:

• Subject had previously received steroid therapy
• Subject was expected to deliver within 12 hours
• Chorioamnionitis
• Dilated 8 cm or more
• Nonreassuring fetal testing

Statistically significant findings:

• 20% reduction in composite outcome (respiratory treatment in the first 72 hours of life + stillbirth + neonatal death within 72 hours of life)  FAVORS TREATMENT
• 33% reduction in severe respiratory complications FAVORS TREATMENT
• Reduction in transient tachypnea of the newborn (6.7% vs 9.9%) FAVORS TREATMENT
• Reduction in bronchopulmonary dysplasia (0.1% vs 0.6%) FAVORS TREATMENT
• Surfactant use (1.8% vs 3.1%) FAVORS TREATMENT
• Lower rate of resuscitation at birth (14.5% vs 17.8%) FAVORS TREATMENT
• Higher incidence of neonatal hypoglycemia (24.0% vs 15.0%) FAVORS PLACEBO
• No difference in infectious morbidities

In March 2016, the Society for Maternal Fetal Medicine (SMFM) issued an SMFM Statement, “Implementation of the Use of Antenatal Corticosteroids in the Late Preterm Birth Period in Women at Risk for Preterm Delivery.”  In short, the organization recommends:

1. In women with a singleton pregnancy between 34 weeks 0 days -36 weeks 6 days of gestation who are at high risk for PTB within the next 7 days (but before 37 weeks of gestation), we recommend treatment with betamethasone (two doses of 12 mg IM twenty four hours apart).
2. In women with preterm labor symptoms in the late preterm (LPT) period, we recommend waiting for evidence of preterm labor, such as a cervical dilatation of at least 3 cm or effacement of at least 75%, before treatment with betamethasone.
3. In women with LPT pregnancies receiving betamethasone, we recommend against use of tocolysis in an attempt to delay delivery to complete the steroid course since it is unclear if the benefits of betamethasone administration are outweighed by the risks of attempts to delay delivery.
4. In women with LPT pregnancies with a potential medical indication for delivery, we recommend betamethasone not be given unless there is a definitive plan for LPT delivery.
5. We recommend that institutions utilize standard guidelines for assessment and management of neonatal hypoglycemia in LPT newborns.
6. We recommend against implementation of the ALPS protocol for conditions not studied in the RCT unless performed as part of research or quality improvement.