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)
• Topical NSAIDs (e.g., diclofenac gel) for musculoskeletal complaints: lower systemic absorption, less studied but generally considered safer than oral NSAIDs; still avoid after 30 weeks
• Physical therapy, heat/cold, acetaminophen combinations for back pain
• Low-dose aspirin (81 mg) is *prescribed* in pre-eclampsia prevention — that's a different context from analgesic ibuprofen

When it might still be used

Occasionally specialists may prescribe short-course ibuprofen in the second trimester for severe acute pain not controlled by paracetamol. This should always be under obstetric supervision, with monitoring of amniotic fluid if use extends beyond 48 hours.

Clinical sources

• FDA Drug Safety Communication (October 2020): "FDA recommends avoiding use of NSAIDs in pregnancy at 20 weeks or later."
• ACOG Practice Bulletin #234 "Prediction and Prevention of Spontaneous Preterm Birth."
• EMA Direct Healthcare Professional Communication on NSAIDs in pregnancy.
• Li DK et al. "Exposure to non-steroidal anti-inflammatory drugs during pregnancy and risk of miscarriage." BMJ 2003 (PMID: 12920013).
• Koren G et al. "NSAIDs in pregnancy: risk assessment." PMID: 16569148.

Bottom line

Avoid ibuprofen from 20 weeks of pregnancy onwards. In the first trimester and early second trimester, short-term occasional use is acceptable if paracetamol isn't enough, but paracetamol remains preferred. From 20 weeks, choose paracetamol or consult your obstetrician for alternatives.

Never use ibuprofen in the third trimester. Always review any pain medication with your obstetrician during pregnancy.