Jefferson: Steroids for women at risk of preterm birth improve lung development and reduces risk of severe respiratory distress in babies. Currently, corticosteroids are recommended for women
at high risk of preterm birth between 23 and 33 weeks of pregnancy, but
not after. A new meta-analysis compiling evidence from six clinical
trials confirms earlier work suggesting that at-risk babies may benefit
from steroids after 34 weeks and suggests that babies born to mothers
who had a scheduled cesarean section after 37 weeks may benefit as well.
The study was published in The BMJ on October 12.
“Respiratory distress remains one of the most common and serious
problems we see in the delivery room that can cause infant mortality,”
says Vincenzo Berghella, M.D., Director of Maternal Fetal Medicine at
the Sidney Kimmel Medical College at Thomas Jefferson University.
Dr. Berghella and co-author Gabriele Saccone, M.D., at the University
of Naples Federico II, compiled data from three previously completed
double-blind clinical trials, including 3,200 women at between 34 to
nearly 37 weeks of pregnancy and at imminent risk of preterm birth.
Babies born in this window are less likely to have fully matured lungs
(incidence of respiratory distress syndrome was 6.7 percent without
steroids, and 2.7 percent with steroids).
The researchers also included data from three trials of 2,498 women
who had a scheduled C-section at 37 weeks or older. Infants delivered by
C-section are also more likely to have respiratory distress because the
natural birthing process stimulates the final stages of lung
development. It is thought that labor contractions and the pressure of
going through the birth canal cause a baby’s lungs to expel amniotic
fluid and begin producing the surfactants that lubricate the lungs and
make it possible to start breathing air. The incidence of severe
respiratory distress in this group was 2.3 percent without steroids and
1.4 percent with steroids.
The authors conclude that a single course of steroids (two shots over
24 hours) may be useful in reducing lung complications in women at high
risk for preterm birth at 34-37 weeks, or for women undergoing a
planned C-section at or after 37 weeks.
However, the meta-analysis also revealed a risk of corticosteroid
administration in this group: there was a higher likelihood of
hypoglycemia, or low blood sugar, in infants whose mothers were treated.
The clinical significance of neonatal hypoglycemia in these babies is
not well known, as these babies did not seem to have any short-term
consequences from the hypoglycemia, and there are not yet any data on
their long-term outcome.