III. Implementation of Labor Analgesia

Education and Informed Consent Prior to Labor Analgesia

It is recommended to establish an anesthesia assessment clinic or a labor analgesia assessment clinic, where healthcare professionals provide education and counseling on pain relief to pregnant and postpartum women. The administration of labor analgesia must be based on the voluntary consent of the parturient; it may only be performed after the parturient herself or her authorized representative has signed an informed consent form.

Preparation for Labor Analgesia

An independent operating space equipped with comprehensive disinfection facilities, monitored and managed in accordance with the hospital’s infection control protocols.

(1) Multifunctional monitor;

(2) Oxygen supply equipment: central oxygen supply/oxygen cylinders, nasal cannulas, and oxygen masks;

(3) Suction equipment: negative-pressure suction device, suction catheter, and sputum suction tube;

(4) Intraspinal puncture kit, analgesia pump;

(5) Fetal heart monitors and neonatal resuscitation equipment;

(6) Adult resuscitation cart, including resuscitation supplies and medications;

(7) Tracheal intubation equipment, including laryngoscopes, endotracheal tubes, oropharyngeal airways, laryngeal masks, and devices for managing difficult airways, among others;

(8) The medical area is equipped with an anesthesia machine and a defibrillator/automated external defibrillator.

(1) Intravenous infusion solutions;

(2) Local anesthetics: lidocaine, ropivacaine, bupivacaine, etc.;

(3) Opioid medications: fentanyl, sufentanil, etc.;

(4) Emergency medicines and 20% fat emulsion, among others.

(1) Anesthesiologist: Must hold a physician qualification certificate and a physician practice license, and be assessed as capable of independently providing labor analgesia.

(2) Other health‑care professionals: Obstetricians, nurses, and other personnel involved in the provision of intrathecal labor analgesia shall hold the relevant qualifications and practice licenses, and shall have completed systematic training in intrathecal labor analgesia.

Timing of the Implementation of Labor Analgesia

The onset of labor analgesia should not be determined solely by the degree of cervical dilation. Once labor has begun, if the parturient requests labor analgesia and no contraindications are identified upon assessment, intrathecal labor analgesia may be initiated at any stage of labor.

Implementation Protocol for Intraspinal Labor Analgesia

1. After labor has begun, the parturient requests;

2. Obstetricians, midwives, obstetric nurses, and anesthesiologists shall conduct the assessment;

3. Develop an analgesic regimen;

4. Sign the informed consent form;

5. Prepare the necessary supplies and establish monitoring of vital signs and fetal heart rate.

6. Establish intravenous access;

7. Perform intrathecal analgesia procedures;

8. Pain management;

9. Following the completion of labor analgesia, the patient will be observed for 2 hours before returning to the ward.

Conduct follow-up within 10–24 hours, closely monitor the patient’s recovery after analgesia, and promptly manage any associated complications.

Monitoring During Labor Analgesia

During analgesia, vital signs (respiration, heart rate, blood pressure, body temperature, and pulse oximetry) as well as fetal heart rate are continuously monitored and recorded. For intrathecal labor analgesia, vital signs should be assessed every 2–5 minutes following the initial injection (including the test dose) and for 20 minutes after the first bolus; if additional doses are administered to manage breakthrough pain, monitoring should be performed every 5–10 minutes for up to 30 minutes. After completion of labor analgesia, patients should remain under observation for an additional 2 hours, and may return to their rooms only if no abnormalities are detected.

During analgesia, uterine contraction pain was assessed using the Visual Analog Scale (VAS); a VAS score ≤3 was considered effective analgesia. When necessary, maternal motor block was evaluated using the Modified Bromage Score.

Division of Responsibilities

During labor and delivery, obstetricians, anesthesiologists, anesthesia nurses, midwives, and neonatologists should collaborate closely, each fulfilling their respective roles to ensure the safety of both mother and infant.

(1) Pre-delivery analgesia assessment;

(2) Provide education to the postpartum mother and her family, and obtain signed informed consent;

(3) Labor analgesia procedures;

(4) Management of labor analgesia, with timely intervention for inadequate analgesia and any adverse events;

(5) Anesthesia for cesarean section performed during labor;

(6) Participate in the emergency resuscitation of parturients with abnormal conditions;

(7) Complete the labor analgesia record;

(8) Management of complications following labor analgesia.

(1) Prepare and dispense medications;

(2) Assist anesthesiologists in performing labor analgesia procedures;

(3) Assist with pain management, monitor and observe the parturient’s vital signs, and promptly report any abnormalities.

(4) Assist anesthesiologists in administering anesthesia for maternal resuscitation and for transfer‑to‑cesarean delivery.

(5) Replenishment of supplies and medications; billing.

(6) Equipment cleaning, maintenance, and record-keeping;

(7) Follow-up after labor analgesia.

(1) Assess the parturient and determine the mode of delivery;

(2) Labor management;

(3) Management of obstetric complications;

(4) In cases of abnormalities or emergencies, decide to terminate vaginal delivery and perform a cesarean section.

(1) Establish peripheral venous access;

(2) Position the parturient in the lateral decubitus position or the semi-sitting position.

(3) Monitor the mother’s vital signs, uterine contractions, and fetal heart rate, among other parameters.

(4) Monitor the progress of labor and adjust uterine contractions.

(5) Report any abnormal findings to the obstetrician and anesthesiologist.

Neonatal assessment and resuscitation.

Diet and Fluid Management During Labor Analgesia

Once labor has begun, the parturient should avoid solid foods to prevent aspiration in case of emergencies. During delivery, clear fluids—such as water, non‑carbonated fruit juices, sugar‑sweetened beverages, tea, coffee, and sports drinks—may be administered as appropriate. Prior to analgesia, peripheral intravenous access should be established; the type and rate of fluid infusion should be determined based on fasting status and any comorbid conditions. Urine output should be monitored throughout, and fluid administration should be maintained until the end of labor, adjusted according to the mother’s physiological needs and clinical condition.

IV. Operational Guidelines for Labor Analgesia Techniques

The intrathecal analgesia techniques discussed in this consensus primarily include epidural analgesia, combined spinal–epidural analgesia, and single-shot intrathecal analgesia. Practitioners may select the most appropriate technique based on their procedural experience, institutional protocols, and clinical circumstances.

Epidural labor analgesia technique

Epidural analgesia for labor provides reliable and well‑controllable pain relief with minimal maternal and fetal adverse effects. The indwelling epidural catheter can also be used for cesarean delivery anesthesia in emergency situations, making it one of the most widely employed methods of labor analgesia in China today.

(1) Prepare the relevant medications, supplies, and equipment;

(2) Initiate monitoring of blood pressure, pulse oximetry, and fetal heart rate;

(3) Initiate intravenous fluid replacement;

(4) Assist the parturient in assuming a position (lateral or sitting).

(5) Perform epidural puncture at the L2–3 or L3–4 interspace.

(6) Leave the epidural catheter in place and administer a test dose.

(7) After the test dose is negative, securely fix the catheter; have the parturient lie in a left- or right‑lateral decubitus position, avoiding the supine position.

(8) Administer an epidural bolus;

(9) Monitoring and assessment (see the monitoring during labor analgesia above);

(10) Connect and initiate the analgesic infusion device.

This includes local anesthetics and opioids. It is recommended to use low‑concentration local anesthetics in combination with opioids, which can achieve satisfactory analgesia, reduce the incidence of motor nerve blockade and instrument‑assisted delivery, and minimize the impact on labor duration.

A test dose of 3 mL of 1.5% lidocaine is recommended (with the option to add epinephrine at 1:200,000 or 1:400,000). Epinephrine should be used with caution in pregnant women with hypertensive disorders, preeclampsia, or heart disease. After confirming no adverse reactions, a single bolus dose of 6–15 mL may be administered. Table 1 lists commonly used epidural analgesia loading doses and the typical drugs and concentrations employed during the maintenance phase; individualized dosing is advised.

Table 1  Epidural Analgesia Commonly used Medicine Concentration

During the maintenance phase of analgesia, patient-controlled epidural analgesia (PCEA) combined with continuous epidural infusion (CEI) or programmed intermittent epidural bolus (PIEB) administration is recommended. The settings of the analgesia pump and the drug concentrations should be adjusted according to the level of pain. For example, an analgesia pump containing a mixture of 0.08% ropivacaine and 0.5 μg/mL sufentanil:

(1) CEI+PCEA parameter settings: background infusion rate of 6–15 mL/h, patient-controlled bolus dose of 8–10 mL per administration, and lockout interval of 15–30 minutes.

(2) PIEB + PCEA parameter settings: bolus dose 8–12 mL, interval 45–60 minutes, patient-controlled dose 8–10 mL per administration, and lockout time 15–30 minutes.

Combined spinal-epidural analgesia

Combined spinal–epidural analgesia is the simultaneous use of intrathecal and epidural anesthesia, offering rapid onset and excellent pain relief; however, clinicians should remain vigilant for the risk of fetal bradycardia and pruritus associated with intrathecal opioid administration.

(1) Preparation, monitoring, and fluid replacement are the same as for epidural analgesia;

(2) Select the L3–4 interspace (preferred) or the L2–3 and L4–5 interspaces for epidural puncture (L3–4 is preferred; given variability in the termination point of the cauda equina, it is advisable to aim slightly lower rather than higher).

(3) Employ the needle-in-needle technique to penetrate the dura mater.

(4) After confirming cerebrospinal fluid reflux, administer the medication; common drugs and their dosages for subarachnoid space administration are listed in Table 2.

(5) Leave the epidural catheter in place, secure it properly, and position the parturient in a left lateral decubitus position.

(6) Monitoring and assessment (see the monitoring during labor analgesia above);

(7) Before administering the drug into the epidural space, inject a test dose.

(8) With a negative test dose, connect the epidural drug infusion device; refer to the epidural analgesia protocol for medication administration into the epidural space (see Table 1).

(9) Management of epidural analgesia.

Table 2 Common Doses of Drugs Administered into the Subarachnoid Space

Single-shot subarachnoid labor analgesia technique (SSS)

Single-dose subarachnoid analgesia is suitable for deliveries expected to occur within a short time frame. In multiparous women, where labor progresses rapidly, this technique is a recommended method of pain relief. The drugs and doses for subarachnoid administration can be referenced in Table 2; individualized dosing is advised.

Intravenous labor analgesia

When intraspinal labor analgesia is contraindicated, intravenous labor analgesia may serve as an alternative; however, it must be administered with due caution, taking into account staffing and equipment resources. Throughout the analgesia period, close monitoring of maternal vital signs and fetal heart rate is essential to prevent maternal respiratory depression and fetal intrauterine distress.

V. Abnormalities in Labor Analgesia and Their Management

Incomplete block/Block failure

During labor analgesia, a sudden, severe exacerbation of pain that persists despite patient-controlled analgesia is referred to as breakthrough pain. When managing breakthrough pain, a comprehensive assessment of the pain’s character and location, along with obstetric factors, should be conducted before implementing appropriate interventions.

This includes the nature, severity, and location of the pain, the progress of labor, obstetric factors (such as uterine rupture, dystocia, and placenta accreta), and other possible causes (such as bladder overdistension, among others).

Assess the level of blockade for intrathecal analgesia, verify the position and depth of the epidural catheter, confirm the drug concentration and infusion rate, and troubleshoot any malfunctions in the drug delivery system (e.g., pump failure, catheter disconnection).

Based on the manifestations of inadequate analgesia, consider potential causes and implement appropriate management strategies (see Table 3).

Table 3: Manifestations, Causes, and Management of Inadequate Analgesia During Labor

Accidental dural puncture

Unintended dural puncture (UDP) caused by an epidural needle or epidural catheter can lead to post-dural puncture headache (PDPH) in parturients. PDPH typically occurs in the upright position, worsens with a change from supine to upright or sitting, and improves when lying down. Associated symptoms include neck pain and stiffness, photophobia, tinnitus, hearing impairment, and nausea. In most cases, PDPH resolves spontaneously, usually within two weeks.

When, following assessment, intrathecal labor analgesia can be continued, the interspace should be changed—typically the previous one—and the epidural catheter reinserted. It should be noted that drugs administered into the epidural space may pass through a dural breach into the subarachnoid space, resulting in a high‑level block. Therefore, analgesic agents should be given initially in small, incremental doses, with dosage adjustments made according to the parturient’s response.

See the “Expert Consensus on the Prevention and Management of Complications of Intraspinal Anesthesia (2017).”

Abnormal fetal heart rate

Assist the obstetrician in ruling out obstetric causes. Fetal bradycardia induced by intrathecal opioid administration usually resolves with appropriate management. Management strategies include positioning the mother in the left lateral decubitus position, administering supplemental oxygen, and maintaining continuous fetal heart rate monitoring; addressing and correcting maternal hypotension; temporarily discontinuing oxytocin; and, if necessary, using tocolytic agents such as nitroglycerin or terbutaline. Continuously monitor fetal heart rate variability and remain prepared for intrauterine fetal resuscitation at any time; perform an emergency cesarean section when indicated.

Severe motor retardation

Severe motor block is commonly observed following repeated single‑dose injections or prolonged continuous infusion of local anesthetics; it can impair the mother’s mobility and, during the second stage of labor, lead to maternal fatigue, thereby increasing the rate of instrumental delivery. Management strategies include adjusting the drug infusion—reducing the infusion rate or the concentration of the local anesthetic—and, if necessary, discontinuing administration.

Conversion to cesarean section during labor analgesia

An indwelling epidural catheter for intraspinal labor analgesia can be used for cesarean delivery anesthesia; however, inadequate analgesia may indicate a failure of its use in this setting. Possible causes include epidural catheter displacement or dislodgement, intradural septa, and epidural–subarachnoid adhesions. The choice of anesthetic technique should be guided by the maternal and fetal conditions, the adequacy of labor analgesia, available medical resources, and the level of anesthetic expertise. Key management considerations include:

VI. Adverse Reactions to Intrathecal Labor Analgesia and Their Management

Compared with other intraspinal blocks, standardized intraspinal labor analgesia involves lower drug doses and reduced local anesthetic concentrations, resulting in infrequent adverse reactions. An overview is provided below:

Hypotension

Assess the underlying causes of hypotension and rule out extracorporeal obstetric factors. Treatment measures include positioning the mother, administering oxygen, and providing intravenous fluids; if necessary, vasoconstrictor agents such as phenylephrine or ephedrine may be administered.

Fever

The pathogenesis of maternal fever (core temperature ≥38°C) associated with epidural analgesia may be linked to a non‑infectious inflammatory response. Risk factors for fever include primiparity, premature rupture of membranes, prolonged labor, pregnancy‑specific physiological changes, the pro‑inflammatory effects of local anesthetics, and the technical aspects of epidural blockade. Currently, no effective preventive measures are available; prophylactic use of acetaminophen or antibiotics does not prevent fever. Management should be tailored to the clinical course and diagnostic findings, employing symptomatic interventions such as physical cooling, adequate fluid replacement, anti‑infective therapy, and pharmacologic antipyresis. In the absence of fetal bradycardia or other maternal abnormalities, analgesia may be continued, and vaginal delivery can proceed.

Itching

It is commonly observed following intrathecal opioid administration. Its severity correlates with the dose of opioids used; in most cases, no treatment is required, as the pruritus is self‑limiting. Available therapeutic agents include μ‑opioid receptor antagonists (such as naloxone and naltrexone), partial μ‑opioid receptor antagonists, and 5‑HT3 receptor antagonists, among others.

Nausea and vomiting

This may be related to intrathecal opioid administration or secondary to hypotension following intrathecal analgesia. Pregnancy, pain, and delayed gastric emptying can also contribute to maternal nausea and vomiting. In the event of severe nausea and vomiting, blood pressure should be monitored promptly; if hypotension develops, it should be corrected without delay. Metoclopramide and 5-HT3 receptor antagonists may also be administered.

Urinary retention

Transient urinary retention or voiding dysfunction during labor can be managed with indwelling urinary catheterization or intermittent catheterization, and function typically returns once labor analgesia is discontinued. Encouraging early ambulation and urination after delivery can help reduce the incidence of postpartum urinary retention.

Chills

This is often associated with maternal stress or altered thermoregulatory responses and does not require specific intervention. Avoid excessive warming, as it may increase the risk of fever during labor. Following delivery, intravenous administration of medications such as pethidine, tramadol, or butorphanol can provide symptomatic relief.

Local anesthesia can cause systemic toxic reactions.

An unintended intravascular injection of a drug administered into the epidural space can lead to systemic toxicity from the local anesthetic. Clinical manifestations include central nervous system symptoms such as maternal restlessness, dizziness, tinnitus, perioral paresthesia, dysarthria, seizures, and loss of consciousness, which may be accompanied by cardiovascular signs including hypertension, bradycardia, ventricular tachycardia, and ventricular fibrillation. Prevention and management strategies are outlined in the “Expert Consensus on the Prevention and Management of Complications of Intraspinal Blockades (2017)”; however, it should be noted that during treatment, the uterus should be maintained in a left lateral tilt, and continuous monitoring of maternal vital signs and fetal heart rate is essential. When administering therapeutic agents, vigilance is required regarding the potential for neonatal depression, and preparations for emergency cesarean delivery must be in place. In the event of maternal cardiac arrest, advanced maternal life support and neonatal resuscitation should be initiated immediately.

High-level block or total spinal anesthesia

It may occur when a local anesthetic intended for epidural analgesia inadvertently enters the subarachnoid space, resulting in high‑level blockade or total spinal anesthesia. Clinical manifestations include maternal agitation, severe hypotension, dyspnea, aphonia, loss of consciousness, and fetal heart rate abnormalities. For prevention and management, refer to the “Expert Consensus on the Prevention and Management of Complications of Intrathecal Blockade (2017)”; key points in diagnosis and treatment are outlined under the section on systemic toxicity of local anesthetics.

Nerve injury

Neurological injury following intrathecal labor analgesia typically manifests as postpartum impairment of lower‑extremity sensation and/or motor function. The etiology is complex; not all neurological complications arising after labor analgesia are attributable to the intrathecal block, as they may also result from pregnancy and delivery—such as fetal macrosomia, prolonged labor, malpresentation, forceps delivery, or particular birthing positions—and thus require careful differential diagnosis and management. For prevention, diagnosis, and treatment of nerve injury caused by intrathecal blockade, refer to the “Expert Consensus on the Prevention and Management of Complications of Intrathecal Blockade (2017).”

Back pain

Approximately more than half of postpartum women experience back pain during pregnancy or the puerperium. The most significant risk factors for postpartum back pain are a history of antepartum back pain and inadequate postpartum weight management. Short‑term back pain is often associated with soft‑tissue injury at the puncture site and typically resolves spontaneously without intervention. Chronic postpartum back pain, in most cases, is not directly related to intrathecal analgesia.

VII. Quality Control of Labor Analgesia

The implementation of labor analgesia requires multidisciplinary collaboration. As the primary providers, the Departments of Anesthesiology and Obstetrics should establish a quality‑control and safety committee for labor analgesia. Continuous improvement in the quality and management of labor analgesia should encompass institutional protocols, personnel management, facility infrastructure, and procedural standards. The committee should conduct regular reviews and evaluations of labor‑analgesia implementation quality, maternal satisfaction, complication rates, and medical documentation, with the aim of further enhancing the quality of labor analgesia and obstetric anesthesia, thereby providing robust safeguards for delivery‑room safety and maternal–infant health.