What are the options for labor analgesia (pain relief during labor)?

From the Guidelines

Labor analgesia involves various methods to manage pain during childbirth, with epidural analgesia being the most effective option, and the choice of analgesia should be based on the woman's preferences, medical history, and stage of labor, with consideration for potential side effects such as hypotension with epidurals or respiratory depression with opioids, as recommended by the most recent guidelines from the obstetric anaesthetists' association 1. The main options for labor analgesia include:

• Epidural analgesia, which can be administered as a combination of local anesthetics (like bupivacaine 0.0625-0.125% or ropivacaine 0.08-0.2%) with opioids (fentanyl 1-2 mcg/ml or sufentanil 0.2-0.4 mcg/ml) 1
• Patient-controlled epidural analgesia (PCEA), which allows women to self-administer additional medication as needed, usually with a basal rate of 5-12 ml/hour, bolus doses of 5-10 ml, and a lockout interval of 10-20 minutes
• Intravenous opioids, such as fentanyl (50-100 mcg) or remifentanil (0.25-0.5 mcg/kg), for women who cannot receive epidurals
• Non-pharmacological methods, such as breathing techniques, hydrotherapy, massage, and transcutaneous electrical nerve stimulation (TENS)
• Nitrous oxide (50% mixed with oxygen), which offers another option with minimal side effects For maintenance of labor analgesia via an intrathecal catheter, bupivacaine 0.1–0.125% (or equivalent) with 2–2.5 lg.ml-1 fentanyl (or equivalent) are suitable solutions, and low-dose local anaesthetic solutions may be given either as intermittent boluses or as a continuous infusion 1. It is essential to monitor maternal blood pressure, sensory and motor block, and fetal heart rate during labor analgesia, and to have clear guidelines for the management of intrathecal catheters in labor and for delivery, as recommended by the obstetric anaesthetists' association 1.

From the FDA Drug Label

Bupivacaine hydrochloride produced developmental toxicity when administered subcutaneously to pregnant rats and rabbits at clinically relevant doses. This does not exclude the use of bupivacaine hydrochloride at term for obstetrical anesthesia or analgesia (see LABOR AND DELIVERY). Labor and Delivery SEE BOXED WARNING REGARDING OBSTETRICAL USE OF 0. 75% BUPIVACAINE HYDROCHLORIDE. Bupivacaine hydrochloride is contraindicated for obstetrical paracervical block anesthesia. Local anesthetics rapidly cross the placenta, and when used for epidural, caudal, or pudendal block anesthesia, can cause varying degrees of maternal, fetal, and neonatal toxicity

• Epidural anesthesia is an option for labor analgesia, using medications like bupivacaine hydrochloride.
• Caudal anesthesia is another option for labor analgesia.
• Pudendal block anesthesia can also be used for labor analgesia. However, bupivacaine hydrochloride is contraindicated for obstetrical paracervical block anesthesia.

Opioids cross the placenta and may produce respiratory depression and psycho-physiologic effects in neonates An opioid antagonist, such as naloxone, must be available for reversal of opioid-induced respiratory depression in the neonate. Remifentanil hydrochloride for injection is not recommended for use in pregnant women during or immediately prior to labor, when other analgesic techniques are more appropriate

• Remifentanil hydrochloride for injection is not recommended for labor analgesia due to potential risks to the neonate.

2 3

From the Research

Options for Labor Analgesia

The options for labor analgesia include:

• Epidural analgesia: a method that provides high-quality pain relief of rapid onset and prolonged duration, while minimizing maternal side-effects and impact on the fetus or labor outcome 4, 5, 6
• Patient-controlled epidural analgesia (PCEA): a technique that allows patients to control their own analgesia, which has been shown to improve maternal satisfaction 4, 5, 7
• Combined spinal-epidural analgesia: a refinement that appears to be extremely promising but awaits further investigation 4
• Intravenous patient-controlled analgesia (IV PCA) with remifentanil: an alternative to epidural analgesia that provides satisfactory pain relief, but may have more side effects such as sedation and low haemoglobin oxygen saturation 8
• Fentanyl patient-controlled analgesia (PCA): an option that may not provide the same level of analgesia as epidural methods and has a higher incidence of side effects such as nausea and/or vomiting and sedation 7
• Remifentanil PCA: an option that may provide superior analgesia to fentanyl PCA at an early time point, but may increase the incidence of oxygen desaturation relative to other strategies of delivering epidural solution 7
• Programmed intermittent epidural bolus (PIEB): a method that has been shown to be superior to continuous epidural infusion (CEI) in terms of analgesic efficacy and maternal satisfaction 7
• Computer-integrated CEI and computer-integrated PIEB: methods that have been compared to other delivery modalities of epidural analgesia, but the optimal mode of delivering epidural solution has not been determined 7

Characteristics of Each Option

Each option has its advantages and drawbacks, including:

• Epidural analgesia: effective, but may have complications such as impairment of mobility 4, 5
• PCEA: improves maternal satisfaction, but may require more medication 4, 5, 7
• IV PCA with remifentanil: provides satisfactory pain relief, but may have more side effects such as sedation and low haemoglobin oxygen saturation 8
• Fentanyl PCA and remifentanil PCA: may not provide the same level of analgesia as epidural methods and have a higher incidence of side effects 7
• PIEB: superior to CEI in terms of analgesic efficacy and maternal satisfaction, but may require more medication 7