Is Ibuprofen safe during pregnancy?

The short answer: Avoid ibuprofen after 20 weeks of pregnancy; short-term use in early pregnancy is generally acceptable if other options are not working

Ibuprofen's safety profile changes dramatically across pregnancy. Before 20 weeks (first trimester and early second), occasional short-term use is generally considered low-risk but not first-line. From week 20 onwards, the FDA recommends avoiding NSAIDs entirely because of fetal kidney and cardiac effects. Paracetamol is the preferred alternative at every stage.

By trimester

• First trimester (weeks 1–12): occasional short-term use (≤72 hours) has not been consistently linked to birth defects, but some observational studies suggest a small increase in miscarriage risk with early NSAID exposure. Use only if paracetamol is insufficient.
• Second trimester (13–20 weeks): acceptable for very short courses if necessary.
• From 20 weeks onwards: avoid. The FDA issued a 2020 safety communication warning of oligohydramnios (low amniotic fluid), which can develop within 2 days of NSAID start.
• Third trimester (28+ weeks): contraindicated — risk of premature closure of the ductus arteriosus, persistent pulmonary hypertension of the newborn, renal impairment, oligohydramnios, and delayed labor.

Why the third trimester is particularly dangerous

Ibuprofen and other NSAIDs inhibit prostaglandin synthesis. In the fetus, prostaglandins maintain the ductus arteriosus (connection between pulmonary artery and aorta). Premature closure of this vessel leads to pulmonary hypertension and can be life-threatening at birth. NSAIDs also reduce fetal urine output, which is the main source of amniotic fluid.

Safer alternatives

• Paracetamol — first-line analgesic/antipyretic in all trimesters (see our paracetamol pregnancy guide)