Anesthesia for Labor and Delivery

• Analgesia and anesthesia options include neuraxial, locoregional, parenteral analgesia, and general anesthesia.
• Neuraxial methods (epidural or spinal anesthesia) are generally preferred.
• Parenteral opioids are used if neuraxial anesthesia is unavailable, contraindicated, or if the patient prefers to avoid it.
• General anesthesia is reserved for emergency cesarean deliveries.

Neuraxial Anesthesia

• The preferred analgesia approach during labor and delivery.
• Provides effective pain control, allows the patient to remain awake, and avoids neonatal sedation.
• Includes epidural, spinal, and combined spinal-epidural methods.

Epidural Anesthesia

• Offers a gradual onset of pain control.
• It can be continued throughout labor and vaginal delivery.
• The level of analgesia can be increased for cesarean delivery.
• A catheter is placed into the lumbar epidural space.
• A local anesthetic (0.2% ropivacaine, 0.125% bupivacaine) is continuously infused with an opioid (fentanyl, sufentanil) into the epidural space.
• The level of anesthesia can be varied.
• Epidural analgesia does not increase the risk of cesarean delivery.

Spinal Anesthesia

• A single injection into the paraspinal subarachnoid space.
• Has a rapid onset.
• May be used for cesarean delivery for a patient without an epidural catheter in place.
• Used less often for vaginal deliveries because it is short-lasting (2 to 3 hours).
• Sometimes used if vaginal delivery is imminent and the patient desires pain control.
• Small risk of spinal headache afterward.
• Vital signs must be checked every 5 minutes to detect and treat possible hypotension.

Locoregional Analgesia

• Less common methods include pudendal block, perineal infiltration, and paracervical block.

Pudendal Block

• A local anesthetic injected through the vaginal wall bathes the pudendal nerve as it crosses the ischial spine.
• Anesthetizes the lower vagina, perineum, and posterior vulva.
• The anterior vulva, innervated by lumbar dermatomes, is not anesthetized.
• A safe, simple method for uncomplicated spontaneous vaginal deliveries if neuraxial anesthesia is not desired or if labor is advanced.
• Complications: intravascular injection of anesthetics, hematoma, and infection.

Perineal Infiltration

• Infiltration of the perineum with an anesthetic is used in limited circumstances.
• It may be used if a patient has perineal pain even with an epidural or pudendal block in place.
• It may be used for a patient without other analgesia, particularly if a large laceration or episiotomy is anticipated.
• Not as effective as a well-administered pudendal block.

Paracervical Block

• Rarely appropriate because the incidence of fetal bradycardia is > 10%.
• 5 to 10 mL of 1% lidocaine or chloroprocaine is injected at the 3 and 9 o’clock positions.
• Analgesic response is short-lasting.

Parenteral Anesthesia

• Intravenous or intramuscular analgesics are given if neuraxial anesthesia is unavailable.
• The minimum amount required for maternal comfort should be given.
• Analgesics cross the placenta and may depress the neonate’s breathing.
• Neonatal toxicity can occur because the neonate clears the transferred drug much more slowly.
• Fentanyl (100 mcg) or morphine sulfate (up to 10 mg) given IV every 60 to 90 minutes is commonly used.
• If fentanyl or morphine provides insufficient analgesia, an additional dose of the opioid or another analgesic method should be used rather than synergistic drugs.
• If neonatal toxicity results, respiration is supported, and naloxone 0.01 mg/kg can be given IM, IV, subcutaneously, or endotracheally to the neonate.
• Naloxone may be repeated in 1 to 2 minutes.
• Clinicians should check the neonate 1 to 2 hours after the initial dosing with naloxone because the effects of the earlier dose abate.

General Anesthesia

• Typically consists of a hypnotic medication and a paralytic.
• Reserved for an emergency cesarean delivery if neuraxial anesthesia is not available or cannot be administered rapidly.
• Potent and volatile inhalation drugs (isoflurane) can cause marked depression in the fetus.
• Not recommended for routine delivery.
• Rarely, nitrous oxide 40% with oxygen may be used for analgesia during vaginal delivery as long as verbal contact with the woman is maintained.

Postpartum Pain Management

• Use a stepwise multimodal approach with a combination of medications with different mechanisms (nonsteroidal anti-inflammatory drugs, acetaminophen, and/or low-potency opioids) to individualize and optimize pain control.
• Clinicians should engage in shared decision-making with patients about pain control.
• Clinicians should be aware of inequities in the assessment and treatment of pain and avoid bias in clinical decisions regarding pain management.
• For patients who are breastfeeding, acetaminophen and ibuprofen are first-line analgesics.
• Intravenous ketorolac is an acceptable agent, although there are limited data regarding levels in breast milk.
• Patients taking opioid analgesics should be counseled about the risk of central nervous system depression in the individual and in the breastfed infant.
• Codeine-containing medications should be used only if there are no other options, because excessive sedation and neonatal death have been reported.