Women who use painkillers such as ibuprofen during pregnancy are twice as likely to suffer a miscarriage, according to a University of Montreal study.
Specialists warn that tens of thousands of expectant mothers are taking the pills unaware of the dangers.
The major study, which was run by the researchers at University of Montreal, Canada, has found that women who took ibuprofen or similar painkillers just before they conceived until the 20th week of pregnancy were 2.4 times more at risk.
Although there are visible warnings on the drugs’ insert package saying they should not be used in pregnancy, as many as one in six expectant mothers still take them.
The Canadian study involved a group of painkillers known as Non-Steroidal Anti Inflammatory Drugs or NSAIDS, which include OTC’s (over-the-counter) ibuprofen and naproxen.
Aspirin (acetylsalicylic acid) is also in this category although it wasn’t included in the study, while paracetamol is deemed safe.
The Canadian researchers believe taking any number of the drugs can lead to the embryo not being properly implanted in the womb meaning a woman is far more likely to suffer miscarriage, which known as a spontaneous abortion.
Approximately one in eight pregnancies end in miscarriage and the majority happen in the first 12 weeks.
Often there is no obvious cause but older women and those who smoke, drink heavily or are obese are at far higher risk.
The study involved 47,050 women aged 15 to 45 and its results have been published in the Canadian Medical Association Journal.
The participants into the study were asked whether they had taken the painkillers at any time in the first 20 weeks of their pregnancy or two weeks before they became pregnant.
Despite the drug insert package warnings, about 17% of women had taken the drugs – nearly one in six.
Dr. Anick Bérard, researcher at the University of Montreal said:
“We consistently saw that the risk of having a spontaneous abortion was associated with gestational use of diclofenac, naproxen, celecoxib, ibuprofen and rofecoxib alone or in combination.
“Women who were exposed to any type and dosage of non-aspirin NSAID during early pregnancy were more likely to have a spontaneous abortion.”
But doctors pointed out the risks of a woman suffering a miscarriage due to painkillers were very small.
They also said the study did not take into account other possible causes such as smoking and obesity.