A question mark hangs over the use of paracetamol during pregnancy after a study found an association between its use and behavioural problems in children.

The use of paracetamol during pregnancy is associated with an increased risk of behavioural problems in children, suggests new UK research.

However, Australian experts have questioned the data and say further research is needed.

A UK study of more than 8000 pregnant women and their offspring, published in the journal JAMA Pediatrics, found that the use of paracetamol at 18 to 32 weeks gestation was associated with increased risk of hyperactivity.

Maternal paracetamol use at 32 weeks of pregnancy was also linked to a higher risk of emotional symptoms in children.

Paracetamol (Acetaminophen) is generally considered safe in pregnancy and is used by many pregnant women for pain and fever.

However, the longitudinal study conducted by researchers at the University of Bristol found five per cent of the children born to the pregnant participants had behavioural problems by the age of seven.

At 18 weeks of pregnancy, 53 per cent of the mothers reported using paracetamol and 42 per cent reported using it at 32 weeks.

While the authors acknowledge the study had its limitations, including a lack of information on dosage or duration of use, they suggest their findings have important implications on public health advice, given the widespread use of the drug during pregnancy.

Professor of pharmacology Norman Saunders from the University of Melbourne disagrees, arguing such a causal relationship has not been established and the authors claims are "bold".

The authors did not analyse separately possible associations with the different reasons why the paracetamol had to be taken; for example, this might have revealed an association with infections such as flu or cold, which would have been an alternative explanation for the problems identified in children, said Prof Saunders.

Dr Luke Grzeskowiak, a specialist pharmacist at the Flinders Women & Children's medical centre, says further studies are needed before there are any moves to change clinical recommendations about paracetamol use during pregnancy.

Paracetamol is useful in treating fever and different types of pain and it still remains our first choice of treating these conditions during pregnancy, said Dr Grzeskowiak.

He encourages pregnant women to talk to their local pharmacist or go and see their doctor for advice if they are unsure of what to use and for how long to use it.

The key message from this study is only to take paracetamol when absolutely necessary and to take it for the shortest possible duration, not to avoid it completely.