The early cancellation of a trial in southern India suggests that the use of antenatal steroids to prevent respiratory complications after late-preterm birth — a recommended practice in the United States — may not be effective in the developing world.
As reported in Obstetrics & Gynecology, researchers led by Hilda Yenuberi, MD, of Christian Medical College, Vellore, Tamil Nadu, India, stopped the randomized, triple-blinded, placebo-controlled CLAP (Corticosteroids in Late Pregnancy) study at 70% enrollment. An interim analysis found no benefit from prescribing betamethasone vs placebo to women at risk of late-preterm delivery between 34 and 36 and 6/7 weeks of gestation (primary outcome of respiratory distress: 4.9% vs 4.8%, respectively, relative risk [RR], 1.03; 95% CI, 0.57-1.84; number needed to treat = 786).
"These findings may suggest differing efficacy of antenatal corticosteroids in developing countries compared with developed countries ... that should be considered when late-preterm antenatal corticosteroids are administered," the researchers wrote.
The use of steroids in patients at risk of delivery before 34 weeks is widely accepted as a way to prevent neonatal respiratory distress, a common and potentially deadly condition in premature infants whose lungs are not fully developed. However, there's debate over steroid treatment in women who are expected to deliver later than 34 weeks but still preterm.
As the study notes, "the American College of Obstetricians and Gynecologists recommends a single course of betamethasone for pregnant individuals at risk of delivering between 34 and 36 6/7 weeks of gestation on the basis of the ALPS (Antenatal Late Preterm Steroid) trial."
But other randomized trials have reached different conclusions, and steroids are not without risks. Studies have linked prenatal steroids to neurosensory disorders in babies, meaning they're more likely to need hearing aids and eyeglasses, said Kellie Murphy, MD, MSc, professor of obstetrics and gynecology, University of Toronto, Toronto, Ontario, Canada, in an interview. Dr. Murphy, who was not involved in the new trial, added that there are links between steroids and greater likelihood of poorer performance in school,
For the new study, conducted from 2020 to 2022 at Christian Medical College and Hospital in Vellore, India, researchers randomly assigned 423 patients to betamethasone (410 in the interim analysis; average age, 26.8 years) and 424 to placebo (415 in the interim analysis; average age, 26.2 years).
The average age of participants was 26.8 years. All were between 34 and 36 6/7 weeks of gestation and expected to give birth within the next week. A quarter of participants delivered at term, which the authors wrote "may have influenced the primary outcome." The total number of neonates was 883, including 58 twin pregnancies.
There was no significant difference in respiratory distress between groups, "defined as need for oxygen or continuous positive airway pressure or mechanical ventilation for at least 2 hours in the first 72 hours of life." There also were no significant differences in maternal outcomes such as chorioamnionitis or length of hospitalization or neonatal secondary outcomes such as transient tachypnea of the newborn, respiratory distress syndrome, necrotizing enterocolitis, sepsis, hyperbilirubinemia, stillbirth, and early neonatal death.
Serious adverse events occurred in four neonates but none were linked to the intervention.
The study doesn't discuss cost, but a 2019 report suggests that use of betamethasone to prevent neonatal respiratory distress is cost-effective.
"Our findings are contradictory to those of a systematic review, the major contributor of which was the ALPS trial," the authors of the new study reported. "The primary outcome of the ALPS trial, the composite of neonatal treatment in the first 72 hours, was significantly less in the group who received betamethasone (11.6%), compared with the placebo group (14.4%; relative risk [RR], 0.80; 95% CI, 0.66-0.97)."
The study authors, who didn't respond to requests for comment, noted that their trial included twin pregnancies and patients with gestational diabetes; the ALPS trial did not.
Perinatologist Cynthia Gyamfi-Bannerman, MD, MS, chair and professor of Obstetrics, Gynecology, and Reproductive Sciences at the University of California, San Diego, and principal investigator of the ALPS study, said in an interview that the inclusion of twins in the new trial is "a fundamental flaw."
"Because antenatal corticosteroids have not been shown to be useful in twins at any gestational age, it is not surprising that including twins likely moved the findings to the null in this study," she said. "Twins were purposefully excluded from the ALPS trial for this reason."
According to the new study, "the primary outcome among singleton neonates occurred in 4.8% (18/374) who received betamethasone and 5.1% (20/393) who received placebo (RR, 0.94; 95% CI, 0.51-1.75)."
What should clinicians take from the study findings? In an accompanying commentary, Blair J. Wylie, MD, MPH, of Columbia University Irving Medical Center, New York, NY, and Syed Asad Ali, MBBS, MPH, of Aga Khan University, Karachi, Pakistan, wrote that, "in settings similar to the US-based ALPS trial, the practice of administering a course of late-preterm antenatal corticosteroids should be continued, as espoused by our professional organizations."
However, the new study suggests that "research in high-resource environments may not be generalizable to low-resource settings," they write.
Neonatologist Elizabeth Asztalos, MD, MSc, an associate scientist with Sunnybrook Health Sciences Centre in Toronto, Canada, said in an interview that she doesn't worry about pregnant mothers not getting steroids later than 34 weeks. "We have tools in our armamentarium in the NICU setting to help babies if they need it," said Dr. Asztalos, who didn't take part in the new trial. "We can put them on CPAP if they have wet lung. If they have an element of respiratory distress, we can give them surfactants. These bigger babies have more ability to recover from all this compared to a baby who was born at 24, 25, 26 weeks."
For her part, the University of Toronto's Dr. Murphy said decision-making about late-preterm steroids is complicated. "You don't want to miss the opportunity to give to provide benefits for the patients" via steroids, she said. "But on the flip side, it's a double-edged sword. It's not easy. It's not straightforward."
In the big picture, she said, "people need to be really clear why they're giving an intervention and what they hope to achieve."
Christian Medical College supported the study. The authors, Dr. Murphy, Dr. Asztalos, and commentary co-author Dr. Ali have no disclosures. Dr. Gyamfi-Bannerman discloses being principal investigator of the ALPS trial. Commentary co-author Dr. Wylie serves on the ultrasound quality assurance committee of a trial discussed in the commentary.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.