Mode of delivery may matter
The researchers said their analysis indicates that mode of delivery may modify the association between antibiotic exposure during pregnancy and childhood asthma.
Fourteen percent of the children in the study were delivered by cesarean section. Further research may clarify the relationship between antibiotics in pregnancy, mode of delivery, and asthma risk, another doctor who was not involved the study added.
Dr. Santina J.G. Wheat
“I do not think that the evidence indicates that mode of delivery clearly has an impact,” said Santina J. G. Wheat, MD, MPH, associate professor of family and community medicine at Northwestern University in Chicago, “as the number of cesarean deliveries was not large enough to fully support such a statement.
“It will be interesting to see if an association holds in future studies with increased cesarean deliveries,” Dr. Wheat said.
How and why antibiotics were used may be other important factors to investigate, Dr. Duff suggested.
“The authors did not provide any specific information about which antibiotics were used by the mothers, duration of use, and indication for use. Those are very important confounders,” Dr. Duff said. “Perhaps the key exposure is to a particular maternal infection rather than to the antibiotic per se.”
The Danish National Birth Cohort was established with a grant from the Danish National Research Foundation and support from regional committees and other organizations. Its biobank has been supported by the Novo Nordisk Foundation and the Lundbeck Foundation, and follow-up of mothers and children has been supported by the Danish Medical Research Council, the Lundbeck Foundation, Innovation Fund Denmark, the Nordea Foundation, Aarhus Ideas, a University of Copenhagen strategic grant, and the Danish Council for Independent Research. The study was partially funded by the Health Research Fund of Central Denmark Region, which supported one of the authors. Other authors were supported by the DHB Foundation and the Australian National Health and Medical Research Council. One author is affiliated with Murdoch Children’s Research Institute in Australia, where the Victorian Government’s Operational Infrastructure Support Program supports research.
The authors had no competing interests. Dr. Wheat serves on the editorial advisory board of Family Practice News. Dr. Duff had no relevant financial disclosures.