Preterm Birth: Steroids to Avoid Harm?
Additional Steroid Doses Might Cut Lung Problems in Premature Babies; Long-Term Risks Unclear
June 8, 2006 – Giving at-risk mothers more steroids might reduce the lung
problems seen in premature babies.
Preterm births carry a high risk of potentially fatal lung problems – such
as respiratory distress syndrome – in babies whose lungs haven't fully
developed. To reduce that risk, doctors often give women at high risk of
preterm birth a single dose of corticosteroids.
More than one steroid dose might help even more, according to a study
published in The Lancet.
However, the long-term effects of additional steroids aren't yet known, note
the researchers, who included Caroline Crowther, FRANZCOG, professor of
obstetrics and gynecology at Australia's University of Adelaide.
An editorial in The Lancet questions the need for extra steroid
doses and recommends caution "until results from long-term follow-up
studies are known."
There has been concern, the researchers note, that multiple steroid doses
might up women's risk of infection and their babies' risk of abnormal
neurological development and slower growth.
"The efficacy and safety of repeat doses of prenatal steroids is
therefore uncertain," write Crowther and colleagues.
To learn more about the risks, they studied 982 pregnant women judged to be
at risk of preterm birth.
The women, who lived in New Zealand or Australia, all got a single steroid
shot. At the time, they were less than 32 weeks pregnant.
Within a week, researchers randomly split the women into two groups.
One group got a weekly steroid shot until they reached their 32nd week of
pregnancy or were no
longer considered at risk for preterm birth. The other group got a weekly shot
of saltwater as a placebo.
Impact of Multiple Steroid Doses
In the study, fewer babies exposed to multiple steroid doses had respiratory
distress syndrome than those whose mothers got the placebo (33% with multiple
doses; 41% with placebo).
Severe lung disease was also rarer with repeated steroid doses than with the
placebo (12% with multiple doses; 20% with placebo).
"In keeping with these benefits, babies exposed to repeat
corticosteroids needed less oxygen therapy and shorter duration of mechanical
ventilation," write Crowther and colleagues.
For reasons that aren't clear, more women in the repeat steroid group gave
birth by cesarean section than in the placebo group.
The average age at birth (slightly over 32 weeks) and the number of babies
born preterm were similar in the two groups.
Crowther's team plans a follow-up when the babies are 2 years old.
"Whether there are effects on health that continue into childhood and
beyond must await later assessment," the researchers write.
Long-term follow-up studies are "essential," states an editorial in
the same journal by Sven Montan, MD, of the obstetrics and gynecology
department at Sweden's Malmo University, and others.
Montan and colleagues question the need for multiple doses.
"If a preterm baby is not delivered within a week of the mother having
steroids, one is not sure when the baby is going to be born," states the
"Nearly 35% of the infants in the two groups were delivered after 34
weeks. In these cases, outcome would be favorable even after one dose,"
they write. "We wonder whether weekly courses of steroids are warranted in