Pain and discomfort of labor have several origins:

Uterine Ischemia

Uterine ischemia (decreased blood flow, and therefore local oxygen deficit) results from compression of the arteries supplying the myometrium during uterine contractions. Uterine ischemia during the first stage of labor results in visceral pain located over the lower portion of the abdomen.  

Somatic pain

Patients will begin to experience somatic pain toward the end of the first stage of labor and during the second stage of labor. This results from the distention and traction of the peritoneum and uterocervical supports during contractions, pressure against the bladder and rectum, stretching and distention of perineal tissues and the pelvic floor to accommodate fetal passage, and lacerations of soft tissue (e.g., cervix, vagina, and perineum). As labor progresses and the pain becomes more intense and persistent, patients often become fatigued and discouraged.

Neurologic Origins

Pain during labor and birth is caused by distention of the lower uterine segment, stretching of cervical tissue as it effaces and dilates, pressure and traction on adjacent structures (e.g., uterine tubes, ovaries, ligaments), and/or nerves.

Referred pain occurs when pain that originates in the uterus radiates to the:

• Abdominal wall

• Lumbosacral area of the back

• Iliac area

• Gluteal area

• Thighs

• Lower back

Perception of Pain

Perception of pain is related to the patient’s psychological state. Pain is a subjective experience and is defined completely by the person who is experiencing it. Patients will vary in how they perceive and cope with labor pain.  Factors that influence the way in which a patient deals with pain include (see below for more details about these aspects): 

• culture

• age

• previous personal experience with pain

• parity

• the availability of physical, psychological, and emotional support.

Expression of Pain

Pain is expressed through physiologic, sensory, or emotional (affective) reactions. Below is a nonexhaustive list of the various ways pain can be expressed.

Physiologic and Sensory Expressions

• Sympathetic nervous system activity is stimulated in response to anxiety, stress, and intensifying pain, resulting in increased catecholamine levels

• Blood pressure and heart rate increase

• Maternal respiratory patterns change in response to an increase in oxygen consumption

• Hyperventilation, sometimes accompanied by respiratory alkalosis, can occur as pain intensifies

• Placental perfusion may decrease

• Uterine activity may diminish

Affective Expressions

• Increasing anxiety with lessened perceptual field

• Writhing

• Crying

• Groaning

• Gesturing (hand clenching and wringing)

• Excessive muscular excitability throughout the body

Pain management without medications is simple, safe, and has few if any major adverse reactions. It is relatively inexpensive, can be used throughout labor, and provides the patient with a sense of control as they make choices about how to manage their pain.  Most importantly there are no effects on the fetus.

Relaxation and Breathing Techniques:  Relaxation without medication Relaxation methods that do not rely on the use of medication include music, meditation, aromatherapy, hypnosis, acupressure, acupuncture, distraction, counterpressure, touch and massage, warm baths and water therapy, patterned breathing, relaxation techniques, focal point, hot or cold pack, movement, and positioning. 

• Focusing and relaxation techniques reduce tension and stress, allowing the patients to rest and conserve energy in preparation for giving birth.

  1. • The woman and her support person must be aware of and watch for symptoms of respiratory alkalosis, which can result from hyperventilation. These include light-headedness, dizziness, tingling of the fingers, or numbness around the mouth. Having the patient breathe into a paper bag held tightly around her mouth and nose may eliminate respiratory alkalosis.

     • Practicing relaxation and breathing techniques is important for them to be effective in labor.  Examples include:  

• Conscious breathing helps the laboring patient focus on something other than the contractions.

• Varying breathing techniques provide a distraction, thereby reducing the perception of pain and helping the woman maintain control.

• Using imagery, the woman focuses her thoughts on a pleasant scene, a place where she feels relaxed, or an activity she enjoys.

• Her partner can learn how to palpate a woman’s body to detect tense and contracted muscles and use support, feedback, and touch and massage to facilitate the woman’s relaxation and thereby reduce tension and stress.

• Herbal tea can have the additional benefit of maintaining fluid balance while promoting relaxation.

Online Childbirth Education Classes

It is of note that attendance at childbirth education classes has declined in recent years. There is an increasing number of patients who are utilizing online childbirth education rather than attending traditional classes, mainly due to cost and convenience.  While online resources are still valuable, they are not always accurate; you should be prepared to address and assuage any concerns your patient might have about nonpharmacologic pain management during labor.  

Sedatives relieve anxiety and induce sleep. They may be given to a patient experiencing a prolonged early phase of labor when there is a need to decrease anxiety or promote sleep. Sedatives may also be given to augment analgesics and reduce nausea when an opioid is used. 

Barbituates (Seconal)

• Easily cross the placenta and have a long half-life.

• Can cause undesirable side effects, including respiratory and vasomotor depression, affecting both patient and fetus.

• Potential for neonatal central nervous system (CNS) depression.

• Should be avoided if birth is anticipated within 12 to 24 hours.

Phenothiazines (Phenergan) 

• Do not relieve pain.

• Are given with opioids to enhance their analgesic effects as well as to:

  • Decrease anxiety and apprehension.

  • Increase sedation.

  • Reduce nausea and vomiting.

Metoclopramide (Reglan)

• An antiemetic, has been found to effectively potentiate the effects of analgesics and may be a better choice than Phenergan.

Benzodiazepines (Valium, Ativan) 

• When given with an opioid analgesic, benzodiazepines seem to enhance pain relief and reduce nausea and vomiting.

• Cause significant maternal amnesia.

• Disrupts thermoregulation in newborns, reducing their ability to maintain body temperature.

• Flumazenil (Romazicon) is a specific benzodiazepine antagonist that can be administered, if necessary, to effectively reverse benzodiazepine-induced sedation and respiratory depression.

Anesthesia encompasses analgesia, amnesia, relaxation, and reflex activity.  The type of anesthetic or analgesic chosen is determined in part by the labor stage and by the planned method of birth

Local Perineal Infiltration Anesthesia

• Local perineal infiltration anesthesia may be used when an episiotomy is to be performed or to repair lacerations. 

• Rapid anesthesia is produced by injecting approximately 10 to 20 ml of 1% lidocaine or 2% chloroprocaine into the skin, then subcutaneously into the region to be anesthetized. Epinephrine is often added to the solution to localize and intensify the effect of the anesthesia, and to prevent excessive bleeding and systemic absorption by constricting local blood vessels. 

• Injections can be repeated to keep the patient comfortable while repairs following birth are completed.

• To administer an epidural, the patient is positioned as they would be for a spinal block (with back curved or in a modified Sims position) with shoulders parallel, legs slightly flexed, and back arched. A large-bore (16-, 17-, or 18-gauge) needle is inserted into the epidural space, and a catheter is threaded through the needle until its tip rests in the epidural space. The needle is removed, and the catheter is taped in place.

• After the epidural catheter has been inserted and secured, a small amount of medication, called a test dose, is injected to make sure that the catheter has not been accidentally placed in the subarachnoid (spinal) space or in a blood vessel. The likelihood of incorrect placement is increased when the patient is obese.

• After the epidural has been initiated, the patient is positioned preferably on her side; this is done so the uterus does not compress the ascending vena cava and descending aorta, which can impair venous return, reduce cardiac output and blood pressure, and decrease placental perfusion.

• There to be kept in mind during this process.

  • • Hypotension is the most common side effect that occurs after administration of an epidural.  Prior to administration, a bolus of intravenous fluids are infused.

    • Oxygen should be available if hypotension occurs in spite of hydration maintenance with IV fluid and displacement of the uterus to the side.

    • Ephedrine or phenylephrine (vasopressors used to increase maternal blood pressure) and increased IV fluid infusion may be needed.

    • FHR and pattern, contraction pattern, and progress in labor must be monitored carefully because the patient may not be aware of changes in the strength of uterine contractions or the descent of the presenting fetal part.

    • The most common method is the continuous infusion epidural (CIE).  Some providers prefer to use CIE with opioids because it decreases the motor block, allowing the laboring patient more mobility in bed.

    • Patient-controlled epidural analgesia (PCEA) is another method; it uses an indwelling catheter and a programmed pump that allows the patient to control dosing.

    • An epidural may not be given if the patient's platelets are too low (usually <100K)

    • Epidural headaches could be a side effect if there is leaking after the epidural is removed.  This is evident by a patient having a severe headache when sitting upright, but it disappears when laying down.  Anesthesia is called and an Epidural Blood Patch is performed to remedy the problem.  

Combined Spinal–Epidural Analgesia

Combined spinal–epidural (CSE) analgesia is a technique sometimes referred to as a “walking” epidural. It is an increasingly popular approach that can be used to block pain transmission without compromising motor function. Opioid receptors are densely concentrated along the pain pathway in the spinal cord, brain stem, and thalamus; when opioid agonist analgesics are injected here, only a small quantity is needed to produce marked pain relief that lasts for several hours. The most common side effects of opioids administered intrathecally are pruritus and nausea.

• The CSE process is as follows:

  • • The epidural needle is inserted into the epidural space.

    • Before the epidural catheter is placed, a smaller-gauge spinal needle is inserted through the bore of the epidural needle into the subarachnoid space.

    • A small amount of opioid, or a combination of opioid and local anesthetic, is injected intrathecally to rapidly provide analgesia.

    • After, the epidural catheter is inserted as usual.

Epidural and Intrathecal (Spinal) Opioids

Opioids can also be used alone, entirely eliminating the need for a local anesthetic. Opioids administered in this manner do not cause maternal hypotension or affect vital signs. Types of opioids that can be used include fentanyl, sufentanil, or preservative-free morphine. Nonsteroidal anti-inflammatory drugs (NSAID), such as ketorolac (Toradol), indomethacin (Indocin), or ibuprofen (Motrin) may be used postoperatively as well. Common indications for the administration of epidural or intrathecal analgesics is the relief of postoperative pain.

• Epidurally administered morphine after a cesarean birth permits:

  • • Early ambulation

    • Facilitated bladder emptying

    • Enhanced peristalsis

    • Clot formation prevention (e.g., thrombophlebitis) in the lower extremities

• Side effects of opioids administered by the epidural and intrathecal routes include:

  • • Nausea

    • Vomiting

    • Diminished peristalsis

    • Pruritus

    • Urinary retention

    • Delayed respiratory depression

Respiratory Depression Due to Opioid Use

Naloxone should be readily available for use if the respiratory rate decreases to less than 12 breaths per minute, or if the oxygen saturation rate decreases to less than 89%. Administration of oxygen by nonrebreather face mask can also be initiated. 

Effects of an Epidural Block on the Newborn

Analgesia or anesthesia during labor and birth has little or no lasting effect on the physiologic status of the newborn. There is no evidence that the administration of maternal analgesic or anesthetic agents during labor and birth have a significant effect on the child’s later mental or neurologic development.

Contraindications to Spinal and Epidural Analgesia

Some contraindications to epidural analgesia include the following:

• Decreased platelets - generally anesthesia prefers the platelet count to be above 100,000

• Active or anticipated serious maternal hemorrhage. Hypovolemia leads to increased sympathetic tone to maintain blood pressure. Any anesthetic technique that blocks the sympathetic fibers can produce significant hypotension that can endanger both mother and fetus.

• Coagulopathy. If a patient is receiving anticoagulant therapy (e.g., last dose of low-molecular-weight heparin within 12 hours) or has a bleeding disorder, injury to a blood vessel may cause the formation of a hematoma.

• Infection at the needle insertion site. Infection can be spread through the peridural or subarachnoid spaces if the needle traverses an infected area.

• Increased intracranial pressure caused by a mass lesion.

• Allergy to the anesthetic drug.

• Maternal refusal or inability to cooperate.

• Some types of maternal cardiac conditions.

• IV infusion is started using an 18-gauge catheter and requires NPO. 

• Patients are premedicated with a nonparticulate (clear) oral antacid (e.g., sodium citrate/citric acid [Bicitra]) to neutralize the acidic contents. Some anesthesia care providers also order the administration of a histamine H2-receptor blocker such as famotidine (Pepcid), ranitidine (Zantac), or metoclopramide (Reglan) to decrease the production of gastric acid.

• A wedge should be placed under one of the patient’s hips to displace the uterus, preventing compression of the aorta and vena cava and allowing maintenance of cardiac output and placental perfusion. 

• The patient should also be preoxygenated with 100% oxygen by nonrebreather facemask for 2 to 3 minutes.

Informed Consent

Patients have the right to be active participants in determining the best pain-management approach to use during labor and birth. Obstetric care providers and anesthesia care providers are responsible for fully informing patients of alternative methods of pharmacologic pain relief available in the birth setting. Nurses play a part in obtaining informed consent by clarifying and describing procedures, or by acting as the patient’s advocate and asking the obstetric or anesthesia health care providers for further explanation.

Three essential components of informed consent are as follows:

1. The procedure and its advantages and disadvantages must be thoroughly explained in a manner the patient can understand.

2. The patient must agree with the plan of pain management as explained to her.

3. Consent must be given freely without coercion or manipulation from the health care provider.