Researchers from the University of Aberdeen found there were higher instances of preterm birth, still birth, neonatal death and physical defects among women who regularly took over the counter pain relief such as paracetamol and ibuprofen.
Around 30-80% of women globally take painkillers to relieve common pregnancy symptoms, flu, fever and rheumatological conditions. However, researchers say current advice on which medicines are safe for pregnant women is conflicting.
More than 151,000 pregnancies were analysed over a 30-year period and looked at medical notes for those who had taken five common painkillers: paracetamol, ibuprofen, aspirin, diclofenac and naproxen.
The figures showed the number of women taking painkillers throughout their pregnancies doubled from 2008-2015.
While regulators have said paracetamol is safe for pregnant women to take, they have warned about taking non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and aspirin after week 30 of pregnancy.
Aikaterini Zafeiri, from the University of Aberdeen, said: "In light of the study findings, the ease of access to non-prescription painkillers, in combination with availability of misinformation as well as correct information through the internet, raises safety concerns.
"This is especially when misinformed 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.”