Although previous studies have hinted to the contrary—and it's certainly unwise to take them during pregnancy—it's been found that certain common over-the-counter painkillers (NSAID's) like Advil, Motrin, Aleve and Naprosyn, which have long been a source of concern for pregnant women, are not the definitive culprits of miscarriage. As it turns out, prescription NSAIDs are more likely the cause, as discovered in a study of nearly 3,000 pregnant women conducted by Vanderbilt University. 43% of these women used painkillers around conception or early pregnancy. While 13% of all the women (not just the painkiller users) suffered miscarriages, there was nothing to signify that NSAIDs were detrimentlal to the pregnancy.
Concern in the past was due to the fact that Advil and the like affect prostaglandins, hormone-like substances in the body, which head researcher Digna Velez Edwards admits has yet to be 100% proven or mythbusted ("We can never know whether NSAIDs or any other medication are completely safe for pregnant women") because it is unethical to assign a control/variable group of pregnant women to take or not take a certain substance. Experts still advise that over-the-counter painkiller intake should not be taken during pregnancy as a precauation.
CLARIFICATION: As stated above, taking painkillers during pregnancy may cause birth defects and the title has been changed to reflect this as such.
'Over-the-counter pain drugs not tied to miscarriage' [Chicago Tribune]
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