What opioid and dose can be given for pain management after 28 weeks of gestation?

Opioid Selection and Dosing After 28 Weeks Gestation

For pain management after 28 weeks of gestation, morphine is the recommended opioid of choice when strong analgesia is required, and should only be used as rescue therapy after maximizing non-opioid analgesics (acetaminophen and NSAIDs). 1

Critical Timing Consideration

• NSAIDs must be avoided after 28 weeks of gestation due to risk of premature closure of the fetal ductus arteriosus and oligohydramnios 1
• This creates a narrower analgesic window, making the stepwise approach even more critical

Stepwise Pain Management Algorithm After 28 Weeks

First-Line: Non-Opioid Analgesics

• Acetaminophen 975 mg every 8 hours OR 650 mg every 6 hours orally 1
• Non-pharmacologic approaches (ice packs, heating pads, local anesthetic application to perineum if applicable) 2

Second-Line: Short-Acting Opioids (Only if First-Line Inadequate)

• Morphine is the preferred opioid when strong analgesia is required in pregnancy 1
• Hydrocodone 5 mg: limit to 5-10 tablets total for severe pain after vaginal delivery 2, 1
• Use the lowest effective dose for the shortest duration possible 1

Specific Clinical Scenarios

For Labor Pain (≥28 weeks):

• Neuraxial analgesia (epidural) should be strongly encouraged as the most effective method 1
• Continuous epidural infusion with dilute local anesthetics plus opioids minimizes motor block 1
• Early catheter insertion should be considered for complicated pregnancies (twins, preeclampsia) 1

For Cesarean Delivery:

• Intrathecal morphine 50-100 μg administered pre-operatively 2
• Alternative: Epidural morphine 2-3 mg if epidural catheter already in place 2
• Postoperatively: scheduled acetaminophen (avoid NSAIDs after 28 weeks) 1
• Short course of oxycodone only if pain poorly controlled by baseline regimen 1

For Vaginal Delivery:

• Epidural morphine or hydromorphone for significant laceration repairs (requires 24-hour respiratory monitoring) 1
• Ketorolac 15-30 mg IV/IM every 6 hours for maximum 48 hours can be considered if delivery occurs and NSAIDs are no longer contraindicated postpartum 1

Critical Opioids to AVOID

• Meperidine should be avoided due to poor efficacy, multiple drug interactions, and increased toxicity risk 3
• Codeine-containing medications require extreme caution due to variable metabolism and risk of neonatal toxicity in ultra-rapid metabolizers 2, 4
• Opioid agonist-antagonists (nalbuphine, butorphanol) must be avoided as they can precipitate withdrawal 3

Essential Safety Monitoring

• Counsel all patients prescribed opioids about risk of central nervous system depression in both mother and breastfed infant 2
• Monitor neonates for excessive sedation and respiratory depression 2, 4, 5
• Severe pain after vaginal delivery is unusual and should prompt evaluation for complications (hematoma, infection, unrecognized injury) 2, 1

Common Pitfalls to Avoid

• Do not prescribe large quantities of opioids: Leftover medications create risk for diversion and misuse 2
• Do not use NSAIDs after 28 weeks antepartum: Risk of fetal ductus arteriosus closure outweighs benefits 1
• Do not delay neuraxial analgesia in labor: It is the most effective pain management strategy and should be offered early 1
• Do not use opioids as first-line: Always maximize non-opioid approaches first 2

Postpartum Transition (After Delivery)

Once delivery occurs, the NSAID restriction is lifted:

• Ibuprofen 600 mg every 6 hours orally can be resumed postpartum 2, 1
• NSAIDs are safe during breastfeeding (ibuprofen, diclofenac, ketorolac) 1
• Continue multimodal approach with scheduled acetaminophen and NSAIDs, using opioids only for rescue 2