Antibiotics in pregnancy tied to asthma in children: study

The results don't prove that antibiotics caused the higher asthma risk, but they support a current theory that the body's own friendly bacteria have a role in whether a child develops asthma, and antibiotics can disrupt those beneficial bugs.

We speculate that mothers' use of antibiotics changes the balance of natural bacteria, which is transmitted to the newborn, and that such unbalance bacteria in early life impact on the immune maturation in the newborn, said Hans Bisgaard, one of the study's authors and a professor at the University of Copenhagen.

Previous research has linked antibiotics taken during infancy to a higher risk of asthma, although some researchers have disputed those findings.

To look for effects starting at an even earlier point, Bisgaard and his colleagues gathered information from a Danish national birth database of more than 30,000 children born between 1997 and 2003, and followed for five years.

They found that about 7,300 of the children, or nearly one quarter, were exposed to antibiotics while their mothers were pregnant. Among them, just over three percent, 238 children, were hospitalized for asthma by age five.

The study, which appeared in The Journal of Pediatrics, found that by contrast, about 2.5 percent, or 581 of some 23,000 children whose mothers didn't take antibiotics, were hospitalized with asthma.

After taking into account other asthma risk factors, Bisgaard's team calculated

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