Prenatal paracetamol exposure and risk of asthma and elevated immunoglobulin E in childhood

Clin Exp Allergy. 2005 Jan;35(1):18-25. doi: 10.1111/j.1365-2222.2005.02151.x.


Background: We recently found that paracetamol (acetaminophen) use in late pregnancy was associated with an increased risk of early wheezing in the offspring.

Objective: To see whether use of paracetamol in late pregnancy is associated with an increased risk of asthma, wheezing and other atopic outcomes in the child at school age.

Methods: In the population-based Avon Longitudinal Study of Parents and Children, we measured associations of paracetamol and aspirin use in late pregnancy (20-32 weeks) with asthma, hayfever, eczema (n = 8511) and wheezing (8381) in the offspring at 69-81 months, and with atopy (positive skin prick test to Dermatophagoides pteronyssinus, cat or grass, n = 6527) and blood total IgE (n = 5148) at 7 years. We used logistic and linear regression to analyse binary outcomes and log-transformed IgE, respectively, controlling for potential confounders.

Results: Use of paracetamol, but not aspirin, in late pregnancy was positively associated with asthma (odds ratios (ORs), comparing children whose mothers took paracetamol 'sometimes' and 'most days/daily' with those whose mothers never took it, 1.22 (95% confidence interval (CI): 1.06-1.41) and 1.62 (95% CI: 0.86-3.04), respectively; P trend = 0.0037), wheezing (ORs 1.20 (95% CI: 1.02-1.40) and 1.86 (95% CI: 0.98-3.55), respectively; P trend = 0.011), and total IgE (geometric mean ratios 1.14 (95% CI: 1.03-1.26) and 1.52 (95% CI: 0.98-2.38), respectively; P trend = 0.0034), but not hayfever, eczema or skin test positivity. The proportion of asthma attributable to paracetamol use in late pregnancy, assuming a causal relation, was 7%.

Conclusion: Paracetamol exposure in late gestation may cause asthma, wheezing and elevated IgE in children of school age.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetaminophen / adverse effects*
  • Acetaminophen / immunology
  • Adult
  • Analgesics, Non-Narcotic / adverse effects*
  • Analgesics, Non-Narcotic / immunology
  • Anti-Inflammatory Agents, Non-Steroidal / adverse effects
  • Aspirin / adverse effects
  • Asthma / blood
  • Asthma / chemically induced
  • Asthma / embryology*
  • Child
  • Eczema / embryology
  • Female
  • Humans
  • Hypersensitivity / embryology
  • Immunoglobulin E / blood*
  • Logistic Models
  • Longitudinal Studies
  • Odds Ratio
  • Pregnancy
  • Pregnancy Trimester, Third
  • Prenatal Exposure Delayed Effects*
  • Respiratory Sounds
  • Rhinitis, Allergic, Seasonal / embryology
  • Risk


  • Analgesics, Non-Narcotic
  • Anti-Inflammatory Agents, Non-Steroidal
  • Acetaminophen
  • Immunoglobulin E
  • Aspirin