Prenatal Acetaminophen: An Asthma Link?
Pregnant Women Who Take Acetaminophen Could Raise Asthma Risk in Their Kids
The analysis, part of an ongoing study looking at the effect of pollutants
ranging from secondhand smoke to pesticides on children's health, involved 712
nonsmoking mothers of African-American and Dominican ethnicity. All lived in
low-income neighborhoods in New York City.
Once a year, the women were asked detailed questions about whether they or
their children had symptoms of asthma and allergy. They were asked about their
and their children's use of prescription and over-the-counter medications. With
regards to the current analysis, Perzanowski says, "the specific question
that women were asked was, 'Did you take Tylenol in pregnancy, and if so, for
how many days?'" Additionally, their blood was tested for
chemicals that have been implicated in the allergic cascade.
Overall, 34% of the moms took acetaminophen in pregnancy.
Wheezing rates among 5-years-olds were:
- About 22% if their moms didn't take acetaminophen in pregnancy.
- About 30% if they took it for one day.
- More than 35% if they took it for two to four days
- More than 50% if they took acetaminophen for five or more days
Compared with 5-year-olds of moms who didn't take acetaminophen in
pregnancy, those whose moms took it for five or more days were 2.2 times more
likely to have wheezing at age 5. If a mom took acetaminophen for two to four
days, the risk went up 78%. Taking it for one day did not significantly raise
Perzanowski says that the women were also asked how much Tylenol they took,
but the data are not yet fully analyzed. "But it looks like they support
the current findings -- that is, the more Tylenol they took, the greater the
risk their child had wheezing at age 5," he says.
The analysis took into account other risk factors for asthma including
ethnicity, whether the mom had asthma, and whether she smoked during
So what could be happening? While no one knows for sure, Perzanowski says
that acetaminophen use may deplete the lung of an antioxidant called
glutathione. Researchers think glutathione, which is found in the lining of
airways, may play an important role in preventing damage to the lungs.