NEW YORK (Reuters Health) – When testing indicates fetal lung immaturity at 34 weeks’ gestation or more, administration of antenatal corticosteroids does not reduce respiratory problems in the newborn, and the better approach is expectant management to prolong gestation as long as possible.
“Not only does steroid administration appear to have no benefit when administered in the late preterm and early term period, but our findings suggest it may actually be harmful,” conclude Dr. Beena D. Kamath-Rayne, at Cincinnati Children’s Hospital Medical Center, Ohio, and colleagues, in their report in the May issue of Obstetrics & Gynecology
In the background to their study, the authors explain that while the use of antenatal corticosteroids to prevent RDS in preemies born at less than 34 weeks’ gestation is widely supported, little is known about the pros and cons of this approach in women at risk of preterm delivery after 34 weeks. Some obstetricians, they note, do give antenatal steroids in that setting when amniocentesis indicates fetal lung immaturity.
To look into this issue, the team compared outcomes in 362 neonates born between 34 and 38 weeks of gestation after fetal lung maturity testing.
The 184 women with mature fetal lung indices were delivered within a mean of 1.7days. Among the group with immature fetal lung indices, 102 were treated with antenatal corticosteroids and delivered after a mean of 3.4 days, while the other 76 women in this group were managed expectantly without corticosteroids and delivered after an average of 10.9 days.
Rates of adverse neonatal respiratory outcomes were 3.3% in the mature-lung group, 9.8% in the immature-lung group given antenatal steroids, and just 1.3% in the immature-lung group managed expectantly, the investigators found.
Furthermore, according to the report, the adjusted odds ratio for a composite of adverse neonatal outcomes among the infants with immature fetal lung indices was 0.59 for those managed expectantly compared to those born after antenatal corticosteroids.
Dr. Kamath-Rayne and colleagues say the findings agree with recent cohort studies showing that the greatest benefit of antenatal corticosteroids is in neonates born between 29 to 34 weeks of gestation, and is much less for those born at either extreme of preterm gestation.
Summing up, they advise: “We recommend that if delivery is indicated based on the maternal or fetal condition before 39 weeks of gestation, after careful consideration of the risks to the mother and fetus, the mother’s pregnancy should be managed as such without the introduction of possible additional morbidity by administration of antenatal corticosteroids until further evidence is available from randomized controlled trials.”
SOURCE:
Antenatal Steroids for Treatment of Fetal Lung Immaturity After 34 Weeks of Gestation: An Evaluation of Neonatal Outcomes
Obstet Gynecol 2012;119:909–916.
