Research released today backs earlier findings that the painkiller paracetamol, when taken during pregnancy, increases the risk of behavioural problems in children.
The Auckland University research reinforces a similar Danish study earlier this year which found using the drug during pregnancy can increase the risk of attention deficit hyperactivity disorder (ADHD) symptoms in children.
The latest study involved mothers from the Auckland Birthweight Collaborative longitudinal study that began in 1995. Dropout rates of participants meant only infants of European descent were followed.
Almost half of the mothers had used acetaminophen, or paracetamol, while pregnant and Senior Research Fellow John Thompson said that usage was linked to the development of ADHD symptoms in their children.
Dr Thompson said other environmental factors not measured may affect the outcomes and more research was needed to accurately assess the risk and consequences of taking paracetamol.
Medsafe said it will review the research, though it said paracetamol had been taken by many pregnant women without any proven increase in harmful effects.