Epidural
An epidural is the most common form of pain medication used by women during labor and delivery; women have various options available, from the type of epidural received to the dosage administered.
Although there are risks associated with the use of an epidural, these are rare, the failure rate is low, and many risk-prevention techniques are in place to avoid complications.
In addition, although epidural use is commonly associated with the prolongation of the second stage of labor, if fetal health signs are reassuring, epidural use does not directly increase the need for assisted delivery (forceps/vacuum) or cesarean section.
Further, any concerns regarding the latter can be prevented by starting with a lower dose of medication, controlling gradual incremental doses, and even stopping the epidural as full dilation nears.
Background
Women have more options for pain control during labor than previous generations, and significant advances to the epidural have been made since the 1970s and 80s. The use of lower concentrations of anesthesia, and more modern techniques that are patient controlled, give women more adequate pain relief without completely taking away all feeling or ability to push.
An epidural delivers pain medication that stops pain signals traveling from the spine to the brain. An epidural is considered the gold standard for pain relief during labor and is the most common method used in the United States (U.S.).
Epidurals block pain to where the woman feels nothing from the waist down. However, the amount of medication used can vary, ranging from complete numbness to a low-dose form where contractions are made tolerable, but women can also feel their legs and push effectively. Epidurals can also be controlled by the woman – known as “patient controlled epidural analgesia” (PCEA). Further, epidurals already in place can be “topped up” to provide the medication necessary for a cesarean section.
Procedure
An anesthesiologist is the type of HCP who performs epidurals (or a nurse anesthetist). An anesthesiologist is a physician with 12 to 14 years of education (including medical school) and 12,000 to 16,000 hours of clinical training. Anesthesiologists speak to women either before labor, after admission, or during labor to inform them of their pain relief options. Women may also be offered a combination of options.
If a woman chooses to have an epidural, the anesthesiologist will ask her to sit up (most common) or lie on her side while keeping the lower part of her back curved towards the HCP. It is usually recommended that women hug a pillow or their partner to help create this curve that allows the anesthesiologist to better view the anatomy of the spine.
Women need to remain as still as possible during the procedure and therefore the anesthesiologist will likely attempt to perform the procedure immediately after a contraction. If a woman has a contraction while the procedure is still in process, a labor and delivery nurse will help her breathe through it. Epidural placement only requires a few minutes.
At the start of the procedure, the anesthesiologist will numb the area of the back with a local anesthetic (brief sting; usually lidocaine) to lessen any discomfort during the procedure. A long, thin, hollow needle with a plastic catheter will go through the back (pressure) into the space between the spinal cord and spine – known as the epidural space (image here).
Anesthesiologists use saline to help determine if they are in the right place. If the tip of the needle goes too far or is in a ligament, the anesthesiologist will feel resistance when saline, air, or both (harmless) is injected through the needle, and a second attempt can be made. If the anesthesiologist injects saline and feels no resistance, they needle is correctly within the epidural space.
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The needle is removed, but the flexible catheter will remain (see image above) and eventually gets taped to the back (see image below). A small amount of anesthetic is then injected into the epidural space of the spine which is “soaked up” by the nerves. These nerves carry pain signals from the body to the brain. These signals are blocked by the medication.
Pain relief is typically felt within 10 to 20 minutes and women should no longer feel all or part of their lower body. Women with higher doses of anesthetic may not be able to feel or move their legs at all, but will have complete pain relief. Women with lower doses may be able to still feel and move their legs slightly. They may also feel the presence of a contraction but very little pain.
Both opioids and local anesthetics are used in epidurals. Fentanyl (opioid) and bupivacaine (anesthetic) are the most common drugs used in epidurals in the U.S.
The dose of the anesthetic is usually increased gradually to avoid injecting too much at once. The epidural may be attached to a small pump that automatically supplies a small continual dose, which can be stopped at any point. Some women may also be given a pump to administer more medicine when they need it (also stops women from using too much).
Women may wish for the epidural to be stopped as they get closer to 10 cm, to ensure they have a strong ability to push. However, contraction pain from 8 to 10 cm can be the most intense (known as the transition phase).
When the epidural is stopped, the numbness usually lasts about two hours before its effects begin to wear off, which may manifest as a tingling sensation. This is also largely dependent on the types of medications used. Women who wish to get up or walk around will need to ask for assistance.
Women may also receive a urinary catheter, as an epidural can numb the sensation as well as the ability to empty the bladder. If the catheter is placed after the epidural, women will not feel its placement.
Side Effects/Complications
Overall, epidurals have about a 98% satisfaction rate. An epidural may not block all pain, but women can be offered additional medications. Causes of potential failure include the catheter location, the anesthesiologist’s experience, the woman’s anatomy, or labor progresses more quickly than expected and the epidural does not set up in time. Usually when an epidural “fails” (about 12% to 14%), the vast majority can be adjusted or replaced.
It is possible the anesthesiologist has a difficult time getting the injection into the correct space (curvature of the spine, body mass index (BMI)) and may abandon the procedure. The distance between the skin and the epidural space varies depending on age and/or weight. It may be 4 cm in normal-weight adults to potentially 8 cm or more in women with a high BMI.
Epidural use does present with risks of side effects and complications (rare), that are mostly related to the amount of anesthetic used; these can also be minimized if the anesthesiologist starts off with a smaller dose, and then increases it slowly due to a woman’s tolerance.
Potential side effects/complications include:
Itchy skin: Most common side effect, due to opioid administration.
Low blood pressure: Hypotension occurs in about 10% of women; this can make women feel nauseous, but additional medication and fluids can be given through the hand/arm intravenously to alleviate this, including antiemetics (anti-nausea medications). A woman’s blood pressure is constantly monitored during labor.
A study published in November 2020 included participants of greater than 2 cm dilation with or without a request for epidural. Ultrasound studies of the uterine arteries, umbilical artery and fetal middle cerebral artery were performed before insertion of the epidural, and 30, 60 and 90 min after; maternal blood pressure was also continually measured.
Although maternal blood pressure did decrease, preplacental, fetoplacental and fetal blood flow remained stable (decrease in the mother's blood pressure due to epidural use did not appear to affect the fetus).
Headaches: Less than 1 in 100 women will have a headache for a few days after an epidural. A severe headache can be caused if the bag of fluid that surrounds the spine is accidentally punctured, which requires treatment.
A procedure known as a blood patch may be used to seal the puncture, by taking blood from the woman and injecting it into the space. As the blood thickens and clots, it seals the puncture and the headache stops.
Nerve damage: The needle or epidural tube can damage nerves, but this is uncommon and is considered temporary.
Slow breathing: Certain drugs used in the epidural can cause slow breathing or drowsiness; women are monitored for this and it is easily treated.
Fever: Epidurals cause fever in about 23 out of 100 women (compared to 7 of 100 women who use another type of pain medication).
Infection: Infection can occasionally develop around the skin next to the epidural tube but usually does not spread.
Any medication that a woman uses during labor can affect the baby prior to delivery. With any opioid use, the baby can experience a change in heart rate as well breathing problems, drowsiness, and/or reduced muscle tone, but these are temporary.
Epidural use is not expected to have any detrimental effects to the baby, even if breastfeeding begins after delivery – especially with low-dose epidurals.
In very rare cases, an epidural may lead to permanent loss of feeling or movement in one or both legs; when this occurs its usually from direct damage from the epidural needle or catheter, infection, or bleeding in the epidural space. However, anesthesiologists go through extensive training to avoid these complications – women should feel free to ask about the anesthesiologist’s experience with epidurals and how many they have completed.
In addition, one large case-series study determined the risk of permanent nerve damage from epidural use was 1.2 in 100,000; for comparison, the risk of permanent damage from labor and delivery itself is estimated to be 1% (1 in 100).
An epidural is not recommended for women with blood clotting problems, who use blood thinning medications, have neurological disorders, are at risk of heavy bleeding, or in women who had certain prior back surgeries.
Many studies show that an epidural may slow the progress of labor, therefore increasing the risk of assisted delivery or cesarean section. However, prolongation is no longer the primary driver behind assisted delivery. Further, as long as fetal vital signs are reassuring, assisted delivery cannot be directly tied to epidural use, especially when several other options may be tried prior to vacuum or forceps (delayed pushing, oxytocin, lessened epidural).
Additionally, the American Society of Anesthesiologists indicates there is no evidence that epidurals, when used properly, are directly related to an increased risk in the slow progression of labor or cesarean delivery.
Action
Women should direct all questions and concerns regarding epidurals to their HCP.
Anesthesiologists have extensive training and experience; however, women should feel free and comfortable to ask about the anesthesiologist’s experience with epidurals. Women should also be forthright about the type of epidural/dose they would prefer.
Women who desire to have an epidural but are afraid of needles can read more here. Women should also note that after the initial injection of lidocaine, women often feel very little for the rest of the procedure.
Resources
The ASA provides a PDF version of a “Pain Relief Birth Plan”. The second page is most useful as an addendum to a woman’s current birth plan and can be downloaded here.
Medications for Pain Relief During Labor and Delivery (American College of Obstetricians and Gynecologists)
Obstetric Analgesia and Anesthesia (American College of Obstetricians and Gynecologists)