Pain management during labor: Clinical sciences

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Introduction0:00–0:35

Labor is defined as the onset of regular uterine contractions that cause the cervix to efface and dilate. Pain is a natural component of labor and each person experiences it differently.
Supporting your patients’ desires on how to manage their pain in labor is an important part of obstetric care, and all available options should be discussed with each patient, including non-pharmacological or pharmacological options; a combination of both; or they may choose to have no pain interventions.Alright, let’s first talk about when your patient presents with pain during labor, and assessment of their desire for pain management intervention.

Assessing patient desires0:35–1:14

Often, the options for pain management are discussed during prenatal care visits or birthing classes. Some of your patients will have specific desires and plans, while others will take a “let’s see how labor goes” approach and are open to suggestions.
Remember that your patient's desires may change throughout their labor course. It’s completely okay if your patient starts out wishing to avoid all medications and then later in their labor course requests an epidural or another pharmacological option!Okay, let’s review what can be offered when your patient desires non-pharmacological pain management.

Non-pharmacological pain management1:14–1:54

There are lots of different options to help labor pain that are non-pharmacological pain management. These include massage, movement, immersion in water during the first stage of labor, acupuncture, relaxation, aromatherapy, and hypnotherapy.
These can be performed in any order and one isn’t necessarily better than another. Some patients choose to hire a birth doula, or professional labor coach, to provide one-on-one support during labor.
This can be very helpful, especially in patients who want to avoid pharmacological interventions. Next, let’s discuss what can be offered when your patient desires pharmacological pain management.

Pharmacological pain management1:54–2:14

Keep in mind the difference between analgesia and anesthesia. Analgesia is when pain is reduced or relieved.
Anesthesia refers to a pain-free state with or without loss of consciousness. First, let’s talk about parenteral or systemic analgesia.

Parenteral or systemic analgesia2:14–3:28

These include fentanyl, morphine, nalbuphine, butorphanol, and remifentanil. There’s no great difference between these various opioids, and you will find that protocols at different facilities use different types and doses of opioids.
The benefits of opioids include that they’re inexpensive and no advanced expertise is needed to administer. However, their effectiveness is limited, as they do not take away all labor pain completely and wear off after a couple of hours.
The major maternal side effects are nausea and vomiting, and you will need to monitor for respiratory depression. Also keep in mind that, since opioids cross the placenta, you’ll need to watch for changes in the fetal heart rate as well as neonatal respiratory depression.Here’s a clinical pearl!
Opioid agonist–antagonist medications, such as butorphanol and nalbuphine, should be avoided in patients who are taking an opioid agonist as part of opioid use disorder maintenance, since they can precipitate acute withdrawal.Another analgesia option is the inhaled agent nitrous oxide, which has gained a lot of popularity recently.

Inhaled agents3:28–4:06

It’s self-administered using a mouthpiece or facemask in a 50% blend of nitrous oxide and oxygen. Benefits include maternal control over the administered amount, as well as the fact that movement is maintained, additional monitoring is not required, and its effect quickly wears off once the mask is removed.
The main side effects are nausea, vomiting, dizziness, and drowsiness. Of note, it can also be used during repair of vaginal lacerations after delivery.Next are regional or neuraxial analgesia and anesthesia options, which include an epidural or spinal.

Regional/neuraxial analgesia and anesthesia4:06–5:38

Regional and neuraxial methods vary from other options as they require placement by a qualified anesthesia provider. Epidural analgesia is administered by placing a catheter into the epidural space.
Having the catheter in place allows for continuous infusion of medication that will last through labor and repair of vaginal lacerations if needed.
An epidural can also be used in the case of c-section delivery by bolusing the already placed catheter with medication. On the other hand, spinal anesthesia is a single injection into the intrathecal space that provides rapid onset of a dense sensory block.
It is not continuous and wears off after a couple of hours, so it’s commonly used for c-section deliveries only rather than management of labor pain.
Both are a combination of a local anesthetic, such as bupivacaine or ropivacaine, with an opioid like fentanyl or sufentanil.
Lower concentrations of the local anesthetic cause less motor blockade. There are some absolute contraindications, including coagulopathy and space-occupying brain lesions.
Lastly, thrombocytopenia is a relative contraindication, and spinals and epidurals are generally considered safe if the platelet count is above 70,000.An additional option for pain management is local anesthesia like pudendal nerve block or local infiltration.

Local anesthesia5:38–6:28

In a pudendal nerve block, local anesthetics like lidocaine are injected transvaginally into the vicinity of the pudendal nerve, which is located below the ischial spines.
This causes desensitization of the vagina, pelvic floor, and perineum, which are innervated by the pudendal nerve. A pudendal nerve block is generally used in the second stage of labor as the fetus descends.
It can also be used prior to episiotomies, which are only done if absolutely necessary, or for repairs of vaginal lacerations after delivery.
On the other hand, local infiltration of tissue is another option for local anesthesia when repairing lacerations. Finally, let's talk about general anesthesia, which plays a role in pain management during labor, but is usually limited to emergency c-sections when no epidural is available.

General anesthesia6:28–7:04

General anesthesia can also be used when neuraxial anesthesia fails or cannot be performed. However, it is avoided in other situations due to the increased risk of aspiration in labor patients and because the inhaled volatile agents can affect uterine tone.
In addition, a rare but potentially lethal complication of certain anesthetics is malignant hyperthermia. Now that we’ve covered all the options, here are a couple of considerations to keep in mind when discussing pain management with your patients.

Considerations7:04–9:33

First, maternal request for pain medication is a sufficient indication for pain medications. That being said, if your patient is requesting pain medication, it’s a good idea to assess the cervix for dilation.
Generally, if a patient is close to delivery or 10 centimeters dilated, you want to avoid parenteral opioids or an epidural.
This is because of the effect of parenteral opioids on newborns, especially if given close to delivery; while an epidural might not take effect quickly enough.
Also, take note that pharmacological pain management methods do not appear to increase the risk of needing a c-section delivery.
Additionally, while there isn't a formal stepwise approach to pain medications in labor, ultimately the gold standard is the epidural.
Regardless of desired interventions, all high-risk patients should have an anesthesia consultation, either on presentation or prenatally, to aid in quality patient care.
High-risk conditions include cardiac disease such as cardiomyopathy, and congenital or acquired disorders like repaired tetralogy of Fallot; hematological abnormalities such as immune or gestational thrombocytopenia; or patients not desiring blood transfusions, such as Jehovah’s witnesses.
Other high risk conditions include spinal, muscular, and neurological diseases such as prior spinal cord injuries; prior vertebral surgeries; arterial-venous malformations; aneurysms; and Chiari malformations.
You should also think about chronic renal insufficiency; and liver diseases such as hepatitis or cirrhosis, that can result in abnormal coagulation studies.Now, there are also some risk factors for anesthesia complications, such as an anticipated difficult airway, obstructive sleep apnea, and malignant hyperthermia; as well as obstetric complications that might affect anesthesia, such as placenta accreta or nonobstetric surgery during pregnancy.
Lastly, think about other high risk factors, such as body mass index greater than 50, myasthenia gravis, dwarfism, and history of solid organ transplantation.

Review9:33–10:16

Alright, as a quick recap… Pain management during labor is an important part of obstetrical care. Remember, labor can be painful!
Non-pharmacological options include massage, movement, immersion in water during the first stage of labor, acupuncture, relaxation, aromatherapy, and hypnotherapy.
On the flip side, pharmacological options include parenteral analgesia with opioids, inhaled agents like nitrous oxide, regional or neuraxial analgesia and anesthesia with an epidural or spinal, and local or general anesthesia.
Always keep in mind that maternal request is sufficient indication for the administration of pain
Pain management during labor: Clinical Sciences | Osmosis