Generally, unless you are allergic to it, ibuprofen will not cause a miscarriage. However it should only be taken in pregnancy when your doctor says it is ok. I was told to replace ibuprofen with acetaminophen (or Tylenol). If you took ibuprofen while pregnant there is NO NEED to panic. It has NOT been proven that it is linked to miscarriage. But, do ask your doctor. Acetaminophen is the only drug I know that its 100% safe during pregnancy. Generally, the concern with Advil, Aspirin, Ibuprofen, or any other NSAID is a an increased risk of bleeding. Especially in the 1st trimester this is undesirable. The use of any of these medications MUST be approved by your PBGYN or other certified pregnancy provider.