The findings of a new study raise concerns about the potential side effects of antibiotics during pregnancy, indicating children born to mothers who used the medications may face an increased risk of asthma.
According to a report published the month in the Archives of Disease in Childhood, researchers not only linked pregnancy antibiotic use to asthma, but indicate the risk is higher if the child was delivered vaginally.
Researchers from Denmark and Australia conducted a cohort study of more than 96,000 children using data from the Danish National Birth Cohort from 1996 to 2002. Of the more than 5,500 children born to mothers exposed to antibiotics during pregnancy.
Children born to mothers exposed to antibiotics during pregnancy had 14% higher odds of having asthma than children born to women who did not use antibiotics during pregnancy. However, the association was not seen when antibiotics were used during the first trimester, but appeared when use occurred during the second and third trimesters, researchers noted.
In addition, an association between pregnancy antibiotics and asthma was observed in children born vaginally, but not via c-section.
“Antibiotic exposure in mid-to-late pregnancy is associated with higher odds of childhood asthma in vaginally born children,” the researchers determined. “Mode of delivery may modify the association.”
Children exposed to antibiotics and born vaginally faced a 34% higher risk of asthma which required treatment than unexposed children also born vaginally.
The researchers theorize the reason the mother was taking antibiotics in the first place may explain the risk of asthma, not necessarily the use of the antibiotics themselves. For example, maternal infections may be one factor that could increase the risk of asthma. Additionally, the study did not account for other factors like breastfeeding, which has been proven to provide health benefits to the child and reduce the risk of asthma.
Researchers think antibiotic use may alter the mother’s microbiome, or balance of good bacteria, which can have other consequences and can help to strengthen an infant’s immune system.