[Morphine analgesia by the intrathecal route]

Area of Science:

• Obstetrics and Gynecology
• Anesthesiology
• Pharmacology

Context:

• Epidural anesthesia using local anesthetics poses risks for patients with spinal deformities or local anesthetic allergies.
• Alternative labor analgesia methods are needed for specific patient populations.

Purpose:

• To evaluate the safety and efficacy of intrathecal morphine for labor analgesia in patients with contraindications to epidural anesthesia.

Summary:

• Thirty patients received intrathecal morphine (0.008 mg cm-1) due to contraindications for epidural anesthesia.
• Effective pain relief was achieved, with residual pain scores decreasing significantly within 25 minutes.
• No adverse maternal or fetal hemodynamic or respiratory effects were observed; 26 infants had Apgar scores of 9 or more.
• Uterine activity remained unchanged, facilitating vaginal delivery in 27 cases (23 without forceps).
• Low maternal-fetal morphine plasma concentration ratios (<6 mg ml-1) correlated with central analgesia and absence of systemic effects.

Impact:

• Intrathecal morphine offers a safe and effective alternative to conventional epidural analgesia for specific laboring patients.
• The method demonstrates favorable maternal and fetal safety profiles, including minimal systemic absorption and side effects.
• This approach supports successful vaginal deliveries and can reduce the need for operative interventions.