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Prenatal Acetaminophen: An Asthma Link?

Pregnant Women Who Take Acetaminophen Could Raise Asthma Risk in Their Kids

Asthma Rates Skyrocketing Among Kids

The asthma statistics for kids are frightening, Perzanowski says. Nine million U.S. children under 18 have been diagnosed with asthma. Asthma rates in children under 5 shot up more than 160% from 1980 to 1994, according to AAAAI.

Among children in the inner city, the picture is even bleaker. One study found nearly one in three youngsters under age 12 is affected.

While some experts have blamed increased exposure to allergens from cockroaches and mice and to air pollution for the unprecedented rise in asthma rates among these kids, Perzanowski says the timeline doesn't really fit.

Seeking another explanation, his team set out to determine whether taking acetaminophen during pregnancy or young childhood raises the risk of wheezing at age 5.

Study Details

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 the risk.

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