Women who take non-steroidal anti-inflammatory drugs (NSAIDs) or aspirin during pregnancy increase their risk of miscarriage by 80 per cent, finds a study in this week's British Medical Journal. Researchers in California interviewed 1,055 pregnant women immediately after their pregnancy was confirmed. They asked the women about their drug use since they became pregnant, their reproductive history, known or potential risk factors for miscarriage and sociodemographic characteristics.
They found that the use of NSAIDs during pregnancy increased the risk of miscarriage by 80 per cent. The risk was much higher when NSAIDs were taken around conception or were used for longer than a week. Other factors, including drinking alcohol or coffee, did not change the results.
Aspirin was similarly associated with an increased risk of miscarriage but paracetamol was not, regardless of timing and duration of use.
All three drugs work by suppressing the production of prostaglandins (fatty acids needed for successful implantation of an embryo in the womb). Because NSAIDs and aspirin act on the whole body, they could lead to abnormal implantation that predisposes an embryo to miscarriage. In contrast, paracetamol acts only in the central nervous system, which may explain why it has no effect on risk of miscarriage, explain the authors.
The authors say that these findings will need confirmation. Meanwhile, it may be prudent for physicians and women who are planning to be pregnant to be aware of this potential risk and avoid using NSAIDs around conception.
