Researchers called for “strong reinforcement” of official medical advice for pregnant women, especially around the risks of combining certain medications such as taking paracetamol and ibuprofen together.
The Aberdeen University study, which analysed more than 150,000 pregnancies over 30 years, looked at outcomes for women who had taken five non-prescription painkillers: paracetamol, aspirin, and the non-steroidal anti-inflammatory drugs (NSAIDs), diclofenac, naproxen and ibuprofen.
It found that where mothers were exposed to at least one of the five painkillers, babies were 33 per cent more likely to be stillborn, and 56 per cent more likely to die in the first 28 days of life.
In addition, babies were 50 per cent more likely to be born prematurely, 57 per cent more likely to be admitted to a neonatal unit, and 28 per cent more likely to weigh under 2.5kg.
A higher risk was associated with taking paracetamol in combination with NSAIDs.
Taking common painkillers in pregnancy has become more common, researchers warned.
Over the 30-year research period from 1985 to 2015, nearly a third of women (29 per cent) had taken over-the-counter painkillers, but this more than doubled to 60 per cent in the last seven years.
Researchers admitted there may be other factors contributing to the outcomes for babies, as the reason for taking the medication was not recorded. But they said that with up to 60 per cent of women taking these painkillers, they could not all have underlying medical conditions which would cause the increased risks seen in the study.
Aikaterini Zafeiri of Aberdeen University, first author of the paper, said: “The ease of access to non-prescription painkillers, in combination with availability of mis-information as well as correct information through the internet, raises safety concerns.
“This is especially when mis-informed or partially-informed self-medication decisions are taken during pregnancy without medical advice.
“It should be reinforced that paracetamol in combination with NSAIDs is associated with a higher risk and pregnant women should always consult their doctor or midwife before taking any over-the-counter drugs. We would encourage a strong reinforcement of the official advice for pregnant women.”