What are the recommended analgesics for pain management in pregnancy?

Pain Management During Pregnancy: Evidence-Based Recommendations

First-Line Analgesic: Acetaminophen (Paracetamol)

Acetaminophen is the recommended first-line analgesic for mild to moderate pain at any stage of pregnancy, with the lowest effective dose used for the shortest duration necessary. 1, 2

• Acetaminophen has the most favorable safety profile among analgesics during pregnancy, particularly in the first trimester when other options carry greater risks 1, 3
• The Society for Maternal-Fetal Medicine considers acetaminophen a reasonable and appropriate choice for treating pain and fever during pregnancy 2
• Acetaminophen crosses the placenta but transfers into breast milk at levels significantly below pediatric therapeutic doses, making it safe during lactation 1

Dosing Recommendations

• Oral dosing: 975 mg every 8 hours OR 650 mg every 6 hours 4
• Intravenous formulation is safe and effective when oral administration is not feasible 2
• Use the lowest effective dose for the shortest possible duration to minimize any theoretical risks 2

Important Caveats About Acetaminophen

• Recent observational studies have suggested associations with neurodevelopmental outcomes (12-25% increased ADHD risk, 12.9% increased autism risk), but the FDA and SMFM have concluded that "the weight of evidence is inconclusive regarding a possible causal relationship" 2
• These studies have significant methodological limitations including inability to control for confounders, recall bias, and failure to adjust for multiple testing 2
• Despite these concerns, acetaminophen remains the safest option as there is no safer alternative for pain relief during pregnancy 5

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Second-Line Analgesic: NSAIDs (With Critical Timing Restrictions)

NSAIDs can be used during the second trimester only, but are CONTRAINDICATED after 28 weeks of gestation. 1, 6

When NSAIDs Are Appropriate

• Ibuprofen is the NSAID of choice when needed during pregnancy 1, 6
• Dosing: 600 mg every 6 hours by mouth 4
• Ketorolac can be considered for severe pain: 15-30 mg IV/IM every 6 hours for maximum 48 hours (requires respiratory monitoring capability) 4

Critical Contraindications and Timing

• Absolutely avoid NSAIDs after 28 weeks of gestation due to risk of premature closure of the fetal ductus arteriosus and oligohydramnios 1, 6
• Avoid in the first trimester when possible due to potential fetal risks 3
• Contraindicated in women with preeclampsia, especially with acute kidney injury 1
• Never use aspirin in analgesic doses during pregnancy (low-dose aspirin for antiplatelet indications is acceptable if strongly indicated) 1

Postpartum NSAID Use

• NSAIDs are safe and effective for postpartum pain management 1
• Ibuprofen, diclofenac, and ketorolac are all considered safe during breastfeeding with minimal transfer to breast milk 1

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Third-Line: Opioids for Severe Pain

For severe pain uncontrolled by non-opioid options, short courses of low-dose opioids can be considered, with morphine or hydromorphone preferred over other opioids. 1, 3

Opioid Selection and Dosing

• Morphine is the opioid of choice if strong analgesia is required 1
• Hydromorphone is preferred for severe pain requiring opioids 3
• For postpartum pain after vaginal delivery: 5-10 tablets of hydrocodone 5 mg for severe pain not controlled by acetaminophen and NSAIDs 4
• For cesarean delivery: multimodal approach with neuraxial morphine (or hydromorphone), scheduled acetaminophen and NSAIDs, plus short course of oxycodone only if poorly controlled 1

Critical Opioid Precautions

• Avoid meperidine due to poor efficacy, multiple drug interactions, and increased toxicity risk 1, 3
• Avoid opioid agonist-antagonists (nalbuphine, butorphanol) as they can precipitate withdrawal 1, 3
• Prolonged opioid use during pregnancy can result in neonatal opioid withdrawal syndrome 7, 8
• Peripartum opioid administration may cause neonatal respiratory depression requiring naloxone availability 7, 8
• Use the lowest effective dose for the shortest possible duration 1, 3

Monitoring Requirements

• Newborns exposed to opioids during pregnancy must be observed for withdrawal symptoms (irritability, hyperactivity, abnormal sleep, high-pitched cry, tremor, vomiting, diarrhea, failure to gain weight) 7, 8
• Infants exposed through breast milk should be monitored for excess sedation and respiratory depression 7, 8

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Labor Pain Management

Neuraxial analgesia (epidural) should be encouraged during labor as the most effective pain management method. 1, 3

Epidural Recommendations

• Early insertion of neuraxial catheter should be considered for complicated pregnancies (twin gestation, preeclampsia) 1
• Continuous epidural infusion with dilute local anesthetics plus opioids is effective while minimizing motor block 1
• Epidural morphine or hydromorphone can be considered for significant laceration repairs (requires 24-hour respiratory monitoring) 4

Special Considerations for Opioid-Dependent Women

• Women on methadone or buprenorphine must continue their daily maintenance dose during labor to prevent acute withdrawal 1
• Neuraxial analgesia should be strongly encouraged 1, 3
• Never attempt acute withdrawal or opioid cessation before delivery as this can be dangerous or fatal to mother and fetus 1
• Avoid nitrous oxide as it is less effective in opioid-dependent women and increases sedation risk 1

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Postpartum Pain Management Algorithm

After Vaginal Delivery (Opioid-Naïve Women)

1. Non-pharmacologic approaches: Ice packs, heating pads, hydrocortisone, local anesthetic application to perineum 4
2. Scheduled acetaminophen: 975 mg every 8 hours OR 650 mg every 6 hours 4
3. Scheduled ibuprofen: 600 mg every 6 hours 4
4. If inadequate: Ketorolac 15-30 mg IV/IM every 6 hours for 48 hours 4
5. If still inadequate: Short course of low-dose opioids (5-10 tablets hydrocodone 5 mg) 4

Important caveat: Severe pain after vaginal delivery is unusual and should prompt evaluation for unrecognized complications (hematoma, infection, occult laceration) 4, 1

After Cesarean Delivery

• Multimodal approach starting with neuraxial morphine or hydromorphone 1
• Scheduled acetaminophen and NSAIDs as baseline 1
• Short course of oxycodone only if pain poorly controlled 1

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Special Clinical Scenarios

Women with Respiratory Disease/Asthma

• Early epidural analgesia with local anesthetics (with or without opioids) is preferred for labor pain 1
• Use systemic opioids cautiously as they suppress cough and ventilation 1
• Continue usual asthma medications during childbirth 1

Chronic Pain Management

• Non-opioid analgesics should be first-line for chronic pain during pregnancy 3
• If opioids are necessary for pre-existing chronic pain, the associated risks are low with continued use 9
• Discuss family planning and potential pregnancy effects before initiating long-term opioid therapy in reproductive-age women 3
• Do not abruptly taper opioids in pregnant women already receiving them without appropriate expertise due to risks to mother and fetus 3

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Key Clinical Pitfalls to Avoid

• Never prescribe NSAIDs after 28 weeks gestation - this is the most common and dangerous error 1, 6
• Never use meperidine - it has poor efficacy and high toxicity risk 1, 3
• Never use agonist-antagonist opioids in any pregnant woman as withdrawal risk is unknown 1, 3
• Never attempt opioid withdrawal near delivery in opioid-dependent women 1
• Always have naloxone available when using opioids peripartum 7, 8
• Always evaluate for complications when pain is severe or prolonged after vaginal delivery 4, 1