The Pharmaceutical Journal
Vol 269 No 7222 p631
2 November 2002

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Paracetamol use in late pregnancy is linked to wheezing among offspring

Frequent use of paracetamol in late pregnancy (after 20 weeks) may increase the risk of wheezing among offspring, researchers from King's College London and the University of Bristol report (Thorax 2002;57:958).

Dr Seif Shaheen and colleagues asked over 9,000 pregnant mothers who were taking part in the Avon Longitudinal Study of Parents and Children about their use of paracetamol and aspirin when they were 18 to 20 weeks pregnant and again at 32 weeks of pregnancy. The mothers were also asked about symptoms of wheeze and eczema in their children six months after giving birth and at 12-monthly intervals thereafter.

The researchers, who have previously shown a positive association between para-cetamol use and asthma, considered that exposure to paracetamol in early life might influence the development of atopic disease.

They found that frequent paracetamol use and frequent aspirin use during pregnancy were associated with different wheezing patterns. For paracetamol, frequent use (on most days or daily) was reported by 1 per cent of women. In late pregnancy (20 to 32 weeks) this pattern of use, compared with no use, was associated with a doubling in the risk of wheeze in the children when they were 30–42 months old (odds ratio 2.10, 95 per cent confidence interval 1.30–3.41, P=0.003). The association was strongest among children whose symptoms appeared before they were six months old.

There was no evidence that less frequent use, or heavy use of paracetamol before 20 weeks of pregnancy, increased the risk of wheeze in the children born to these mothers. Nor was there any evidence to suggest that frequent use of paracetamol during pregnancy was linked to subsequent eczema in the children.

Frequent use of aspirin was associated with a higher risk of transient infant wheezing, but only in children under 6 months old. This observation was unexpected, say the researchers.

They comment that the proportion of early childhood wheezing in the population that could be attributable to frequent use of these analgesics during pregnancy, assuming a causal relationship, was small (about 1 per cent for paracetamol). "We recommend that paracetamol should remain the analgesic of choice in pregnancy, if used infrequently," they conclude.