Is naproxen (nonsteroidal anti-inflammatory drug, NSAID) safe to use during pregnancy?

Naproxen Use During Pregnancy: Safety Considerations

Naproxen should be avoided during pregnancy, particularly in the third trimester, due to significant risks of premature closure of the ductus arteriosus, oligohydramnios, and other adverse fetal effects. 1, 2

Safety by Trimester

First Trimester

• Naproxen is not known to be significantly teratogenic in humans 3, 4
• However, NSAIDs may interfere with blastocyst implantation, so women actively trying to conceive should avoid these medications 3
• If pain management is needed, acetaminophen is a safer alternative 1

Second Trimester

• Short-term use (7-10 days) at the lowest effective dose may be relatively safe 1, 5
• Limited evidence suggests that brief use for analgesic or antipyretic purposes during this period does not pose substantial risk 5, 6
• However, prolonged use in late second trimester should be monitored due to potential fetal risks 5

Third Trimester

• Naproxen is strongly contraindicated after gestational week 28-32 3, 1, 2
• Significant risks include:
  • Premature closure of the ductus arteriosus
  • Oligohydramnios (reduced amniotic fluid)
  • Pulmonary hypertension in the newborn
  • Impaired renal function
  • Prolonged gestation and labor
  • Increased peripartum blood loss 3, 2, 7

Alternative Pain Management During Pregnancy

1. Acetaminophen is the safest analgesic option throughout pregnancy 1
2. Low-dose prednisone (≤5 mg/day) may be considered for inflammatory conditions when needed 1
3. For women with preeclampsia or at risk, avoid NSAIDs as they may worsen hypertension and kidney function 3

Breastfeeding Considerations

• Naproxen is generally considered safe during breastfeeding 3, 8
• Only small amounts pass into breast milk (approximately 1% of maternal plasma concentration) 2
• The American Academy of Pediatrics considers naproxen compatible with breastfeeding 3
• However, naproxen should be avoided when breastfeeding a neonate with jaundice due to potential bilirubin displacement 3

Clinical Decision Algorithm

1. First assess gestational age:

   • If >28 weeks (third trimester): Do not use naproxen under any circumstances
   • If <28 weeks: Consider the following factors

2. Evaluate need for pain management:

   • For mild to moderate pain: Use acetaminophen as first-line therapy
   • For inflammatory conditions requiring treatment:
     • Consider lowest effective dose of naproxen for shortest duration (only if <28 weeks)
     • Consider alternative medications like low-dose prednisone

3. Monitor for complications if naproxen is used before 28 weeks:

   • Watch for decreased fetal movement
   • Monitor amniotic fluid volume if treatment extends beyond 7 days
   • Discontinue immediately if any signs of fetal distress

Important Caveats

• The FDA pregnancy category for naproxen is C, indicating potential risks 2
• All NSAIDs, including naproxen, should be discontinued by gestational week 32 at the latest 3, 1
• Women with preeclampsia should avoid NSAIDs due to potential worsening of hypertension and renal function 3
• The European Society of Cardiology specifically mentions that naproxen should be withdrawn in any case at gestational week 32 3

In summary, while short-term naproxen use before 28 weeks gestation may carry acceptable risk in certain clinical scenarios, it should be completely avoided in the third trimester, and safer alternatives like acetaminophen should be considered throughout pregnancy whenever possible.