Acetaminophen in Pregnancy: Link to Baby's Asthma?
Study Suggests an Increase in Asthma Risk When Pregnant Women Take Some Painkillers
Painkillers During Pregnancy continued...
In a U.S. study of 1,505 women, the use of acetaminophen did not increase the risk of asthma overall. And in mothers who used it only during the first or third trimesters, it was linked with a reduced risk of asthma.
Researchers cannot explain the link, when found, Beasley says. One speculation is that the breakdown products of the painkiller may increase the risk of inflammation. If the inflammation affects the airway, he says, that could increase the risk of asthma.
The new report ''does strengthen the argument" linking painkiller use during pregnancy with asthma, says Victoria Persky, MD, professor of epidemiology and biostatistics at the University of Illinois at Chicago School of Public Health.
In her own research, published in 2008, she found infants born to women who used acetaminophen in mid to late pregnancy had an increased risk of wheezing in the first year of life. She found no link if the medicine was used early in pregnancy.
However, she says, more data are needed. "I think it's still premature for a public health recommendation."
Another expert, Rebecca Piltch, MD, a San Francisco allergist, agrees that the evidence is preliminary. However, she says, "It is beginning to look like there may be a link at least in some circumstances."
Charles Lockwood, MD, chair of obstetrics, gynecology, and reproductive sciences at Yale University, says the studies have some built-in bias. "Mothers with asthma and frequent upper respiratory infections use more paracetamol and are already at risk for having affected children.”
The American Congress of Obstetricians and Gynecologists does not offer guidance on the use of acetaminophen during pregnancy, says Stacy Brooks, a spokesperson.
''On balance, it is still the safest pain medication," Lockwood says.
Bonnie Jacobs, a spokeswoman for the maker of Tylenol, Johnson & Johnson's McNeil Healthcare, says her experts have not yet evaluated the study.
She withheld comment until the experts had a chance to evaluate the new results thoroughly.