Pudendal Block: Complete Guide to Pain Relief During Childbirth

What Is a Pudendal Nerve Block?

A pudendal nerve block (PDB) is a type of regional anesthesia that numbs the pudendal nerve, which supplies sensation to the vagina, vulva, and perineum. Local anesthetic is injected through the vaginal wall near where this nerve passes through the pelvic floor, blocking pain signals during the final stage of delivery.

The pudendal nerve is one of the main nerves responsible for transmitting pain signals from the lower genital area. It originates from the sacral spine (S2-S4 nerve roots) and travels through the pelvis, passing near a bony landmark called the ischial spine. This consistent anatomical location makes it possible for healthcare providers to accurately target and block the nerve with local anesthetic.

During childbirth, significant pain occurs as the baby passes through the birth canal and stretches the vaginal tissues and perineum. The pudendal nerve carries these pain signals to the brain. By blocking this nerve, a pudendal block can significantly reduce the pain experienced during the second stage of labor—when you push and deliver the baby—as well as during any necessary repairs afterward.

Pudendal block has been used in obstetrics for many decades and remains a valuable pain relief option, particularly in situations where epidural anesthesia is unavailable, insufficient, or contraindicated. It provides targeted pain relief exactly where it's needed most during delivery, while allowing the mother to remain alert and actively participate in the birthing process.

Anatomy of the Pudendal Nerve

Understanding the pudendal nerve's anatomy helps explain why this block is so effective for childbirth. The pudendal nerve is formed from branches of the sacral plexus, specifically the S2, S3, and S4 nerve roots. It exits the pelvis through the greater sciatic foramen, wraps around the ischial spine (a bony projection you can feel inside the vagina), and then re-enters the pelvis through the lesser sciatic foramen.

From there, the pudendal nerve travels along the pelvic sidewall in a channel called Alcock's canal, giving off branches that supply sensation to the clitoris, labia, perineum, and lower vagina. It also provides motor function to muscles of the pelvic floor, including those that control urination and defecation. This is why a pudendal block can occasionally cause temporary urinary retention.

The ischial spine serves as the key anatomical landmark for performing a pudendal block. The nerve passes very close to this bony prominence, making it relatively easy for experienced practitioners to locate and inject anesthetic near it. The injection is typically performed bilaterally (on both sides) to ensure complete pain relief.

How Is a Pudendal Block Performed?

During a pudendal block, you lie on your back with knees bent and legs apart. A midwife or doctor inserts a needle through the vaginal wall and injects local anesthetic near the pudendal nerve on each side. You may feel a brief stinging sensation when the anesthetic is injected, but the procedure is generally well-tolerated.

The pudendal block procedure is typically performed when the cervix is fully dilated and the baby is moving down the birth canal. At this stage of labor, the baby's descent creates the intense pressure and stretching sensations that the pudendal block aims to relieve. The timing is important because administering the block too early means it may wear off before delivery is complete.

Your healthcare provider will begin by positioning you properly. The standard position is lying on your back (supine) with your knees bent and legs spread apart in a lithotomy-like position. This provides the best access to the vaginal canal and allows the provider to accurately locate the ischial spines on both sides.

Next, the provider performs a vaginal examination to identify the ischial spines—the bony landmarks that indicate where the pudendal nerve is located. Using one or two fingers to palpate inside the vagina, they can feel these projections on each side of the pelvis. The nerve passes just behind and below each ischial spine, making this the target area for the injection.

The Injection Process

Once the ischial spine is located, the provider guides a needle through the vaginal wall toward the nerve. Many practitioners use a specialized needle guide called an Iowa trumpet or a similar device, which helps protect the vaginal tissues and ensures accurate needle placement. The needle is typically 10-15 centimeters long and is inserted about 1 centimeter below and behind the ischial spine.

Before injecting the anesthetic, the provider typically aspirates (pulls back on the syringe) to ensure the needle is not in a blood vessel. If no blood returns, they slowly inject the local anesthetic—usually lidocaine or similar agents in doses of 5-10 mL on each side. The anesthetic spreads around the pudendal nerve, blocking pain signal transmission.

You may feel several sensations during the injection: pressure as the provider locates the ischial spine, a brief sting as the needle penetrates the vaginal wall, and a sensation of fullness or stretching as the anesthetic solution is injected. These sensations are usually mild and brief. The entire procedure takes only a few minutes per side.

Alternative Injection Routes

While the transvaginal approach described above is most common during labor, pudendal blocks can also be administered through the perineum (the skin between the vagina and rectum). This transperineal approach is sometimes used after the baby has already been born, when access through the vagina may be difficult or when repairs to the perineum are needed.

In the transperineal technique, the provider injects through the skin of the buttock area, aiming for the same target—the pudendal nerve near the ischial spine. This approach may cause slightly more discomfort initially but achieves the same end result of blocking pain signals from the pelvic floor region.

How Does a Pudendal Block Relieve Pain?

Pudendal block works by depositing local anesthetic around the pudendal nerve, which blocks the transmission of pain signals from the vagina, vulva, and perineum to the brain. The anesthetic prevents the nerve from sending electrical signals, effectively numbing the entire area supplied by this nerve.

Local anesthetics like lidocaine work by blocking sodium channels in nerve cell membranes. Nerves transmit pain signals through electrical impulses that depend on sodium ions flowing into the nerve cells. When local anesthetic molecules bind to these sodium channels, they prevent sodium from entering the cells, effectively stopping the electrical signal in its tracks.

The pudendal nerve is a mixed nerve, meaning it carries both sensory signals (pain, touch, temperature) and motor signals (muscle control). When blocked, you lose sensation in the areas it supplies—primarily the lower vagina, vulva, clitoris, and perineum. Some motor function may also be temporarily affected, which is why you might notice some weakness in pelvic floor muscles.

The extent of numbness depends on several factors: the type and concentration of local anesthetic used, the volume injected, and how accurately the solution is placed near the nerve. When performed correctly, a pudendal block provides excellent pain relief for the stretching and pressure of delivery, as well as for any cuts or tears that need to be repaired.

What Areas Does the Block Cover?

The pudendal nerve provides sensation to a specific region of the pelvis, and the pudendal block numbs precisely these areas. The main areas affected include the lower two-thirds of the vagina, the labia majora and minora, the clitoris, the perineum (the area between the vagina and rectum), and the skin around the anus. This coverage makes the block ideal for the final stages of delivery and for perineal repairs.

Importantly, a pudendal block does not numb the uterus or the upper vagina. This means that you will still feel uterine contractions, which can actually be helpful for knowing when to push. The block primarily targets the pain from vaginal stretching and perineal pressure during crowning (when the baby's head emerges) and delivery of the shoulders.

Because the block doesn't affect the upper birth canal or uterus, it's often used in combination with other pain relief methods. For example, some women use nitrous oxide (laughing gas) during contractions while the pudendal block handles the delivery-related pain. This combination approach can provide comprehensive pain relief throughout labor.

When Is Pudendal Block Used During Labor?

Pudendal block is used during the second stage of labor when the baby is about to be born. It's particularly useful for assisted deliveries with vacuum extraction, for perineal repairs after delivery, and for women who want pain relief for pushing but haven't had or don't want an epidural.

The timing of a pudendal block is crucial for its effectiveness. It's typically administered when the cervix is fully dilated (10 centimeters) and the baby has descended well into the birth canal. At this point, the intense sensations of pushing and the baby moving through the vagina become the primary source of pain—exactly what the pudendal block targets.

One of the most common indications for pudendal block is instrumental delivery. When a vacuum extractor (ventouse) or forceps is needed to help deliver the baby, a pudendal block provides the necessary pain relief for these procedures. The instruments must be placed inside the vagina and around the baby's head, which would be very painful without anesthesia.

Another key use is for perineal repair after delivery. Many women experience some degree of tearing during childbirth, or may have had an episiotomy (a surgical cut to widen the vaginal opening). Repairing these tears requires stitches, which would be quite painful without adequate anesthesia. The pudendal block provides excellent numbness for this repair work.

Ideal Candidates for Pudendal Block

Pudendal block is an excellent option for women who arrive at the hospital in advanced labor and don't have time for an epidural. It can be administered quickly and provides effective pain relief within minutes. Unlike an epidural, which requires careful placement in the spine and typically takes 20-30 minutes to set up and take effect, a pudendal block can be performed bedside in just a few minutes.

Women who want to avoid epidural anesthesia for various reasons may also choose pudendal block. Some women prefer to maintain more mobility during labor, while others have medical conditions that make epidural placement risky. Pudendal block offers an alternative that provides significant pain relief without the systemic effects of an epidural.

Additionally, pudendal block can be useful when an epidural is already in place but isn't providing adequate coverage for the perineal area. This "patchy" epidural situation is not uncommon, and adding a pudendal block can fill in the gaps in pain relief specifically for delivery.

How Long Does a Pudendal Block Last?

The pain-relieving effects of a pudendal block typically last between 1 and 4 hours, depending on the type and concentration of local anesthetic used. This duration is usually sufficient to cover the delivery and any necessary repairs to tears or episiotomy.

The duration of a pudendal block depends primarily on which local anesthetic is used and its concentration. Lidocaine, the most commonly used agent, typically provides 1-2 hours of pain relief. Longer-acting agents like bupivacaine can extend this to 3-4 hours or more. Some practitioners use a mixture of agents to achieve both rapid onset and prolonged duration.

For most uncomplicated deliveries, the block lasts long enough to cover the critical period of crowning and delivery, plus any immediate repairs needed afterward. If the repair takes longer than expected or if the block begins to wear off, additional local anesthetic can be injected directly into the perineal tissues—a technique called local infiltration.

After the anesthetic wears off, sensation returns gradually. You may notice tingling or pins-and-needles sensations as the nerve function returns. Full sensation typically returns within a few hours after the block wears off. Any discomfort from delivery or repairs can then be managed with oral pain medications as needed.

What Are the Benefits of Pudendal Block?

Pudendal block offers several advantages: it provides effective pain relief for delivery and repairs, has minimal effect on the baby, allows the mother to remain alert and push effectively, can be administered quickly when needed, and doesn't require specialized anesthesia equipment or personnel.

One of the primary benefits of pudendal block is its targeted pain relief. By blocking only the nerves that supply the pelvic floor, it numbs exactly the area where pain is most intense during delivery while leaving other sensations intact. This means you can still feel uterine contractions, which helps with timing your pushes effectively.

The minimal effect on the baby is a significant advantage over systemic pain medications. When mothers receive IV pain medications like opioids, these drugs cross the placenta and can affect the baby, potentially causing respiratory depression or drowsiness after birth. With a pudendal block, the local anesthetic is injected directly into the mother's tissues and very little enters the bloodstream, meaning almost none reaches the baby.

Pudendal block allows the mother to remain completely alert and awake throughout delivery. Unlike epidurals, which can sometimes cause significant motor block and difficulty pushing, pudendal block primarily affects sensation rather than muscle strength. Many women find they can push more effectively with a pudendal block because they have some sensation preserved while the intense pain is blocked.

Additional Advantages

The procedure can be performed quickly in urgent situations. When a baby needs to be delivered rapidly—for example, if there are signs of fetal distress—there may not be time to wait for an epidural to take effect. A pudendal block can be administered in minutes and provides almost immediate pain relief, allowing necessary interventions to proceed without delay.

Pudendal block doesn't require the specialized equipment and monitoring needed for epidural anesthesia. It can be performed by trained midwives and physicians using only a needle, syringe, and local anesthetic. This makes it a valuable option in settings where anesthesiologists aren't immediately available, such as smaller hospitals or birth centers.

There are no restrictions on movement or position after a pudendal block. Unlike epidurals, which typically require bed rest due to leg weakness and monitoring requirements, a pudendal block doesn't affect your legs or ability to move. You can change positions as needed to find the most comfortable position for pushing and delivery.

What Are the Risks and Side Effects?

The most common side effect of pudendal block is that numbness may make it harder to feel when and how to push. Rare complications include allergic reactions to the anesthetic (extremely rare), local infection, bleeding at the injection site, or temporary nerve injury. Serious complications are very uncommon.

The most frequently reported side effect of pudendal block is interference with the natural pushing sensation. The pudendal nerve provides much of the sensation that triggers the urge to push and helps you know how to direct your pushing efforts. When this nerve is blocked, some women find it harder to push effectively because they can't feel the pressure and stretching that guides them.

However, this effect varies considerably between individuals. Some women find the pain relief allows them to push more effectively because they're not distracted by intense pain. Others find the reduced sensation challenging. Your healthcare provider can help coach you through pushing even if your sensation is diminished.

Allergic reactions to local anesthetics are possible but extremely rare. True allergy to amide-type local anesthetics (like lidocaine) occurs in fewer than 1% of the population. Symptoms would include skin rash, difficulty breathing, or cardiovascular symptoms. If you've ever had a reaction to local anesthetics (such as at the dentist), be sure to inform your healthcare team.

Potential Complications

Infection at the injection site is a potential risk, though it's minimized by using sterile technique. The vaginal environment contains normal bacteria, so there's always some theoretical infection risk with any vaginal procedure. Clinical experience suggests that actual infections from pudendal block are rare when proper technique is used.

Bleeding or hematoma (blood collection) at the injection site can occur if the needle damages a blood vessel. The pelvic area has a rich blood supply, and some minor bleeding is not unusual. Significant hematomas are uncommon and usually resolve on their own without treatment.

Temporary nerve injury is possible if the needle directly contacts or damages the pudendal nerve. This might cause prolonged numbness, tingling, or weakness in the affected area. Such injuries are typically temporary and resolve within days to weeks as the nerve heals. Permanent nerve damage is extremely rare.

Can Pudendal Block Be Combined with Other Pain Relief?

Yes, pudendal block can be used alone or combined with other pain relief methods. It works well alongside nitrous oxide (laughing gas), TENS, massage, water therapy, and other non-pharmacological methods. It can also supplement an epidural that isn't providing complete coverage.

Many women use multiple pain relief methods during labor, and pudendal block fits well into this multi-modal approach. During early labor, you might use non-pharmacological methods like movement, warm water, massage, or TENS (transcutaneous electrical nerve stimulation). When delivery is imminent and these methods are no longer sufficient, a pudendal block can provide the additional relief needed.

Nitrous oxide (laughing gas) is commonly used alongside pudendal block. Nitrous oxide helps take the edge off contractions and provides a calming effect, while the pudendal block targets the specific pain of vaginal stretching and delivery. Together, they can provide comprehensive pain management for women who don't have or don't want an epidural.

If you have an epidural that's working well for contraction pain but not adequately covering the perineal area, a pudendal block can fill this gap. This situation isn't uncommon—epidurals sometimes provide better coverage to certain areas than others. Adding a pudendal block ensures you have good pain relief for the actual delivery.

Complementary Non-Medical Methods

Pudendal block combines well with supportive care measures that don't involve medication. Continuous labor support from a partner, doula, or midwife has been shown to improve birth outcomes regardless of what pain relief is used. Breathing techniques and relaxation methods remain helpful even when medical pain relief is in place.

Warm compresses applied to the perineum during delivery can provide comfort even with a pudendal block in place. While you may not feel the warmth as intensely due to the numbness, the heat helps relax the tissues and may reduce tearing. Many providers continue using this technique whether or not a block has been administered.

Different positions for pushing can still be used with a pudendal block. Unlike an epidural, which may limit your mobility, a pudendal block doesn't affect your legs or overall ability to move. You can try upright positions, side-lying, or hands-and-knees as preferred—whatever helps you push most effectively.

When Is Pudendal Block Not Recommended?

Pudendal block may not be recommended if the baby has descended too far for safe needle placement, if there's infection at the injection site, if you're allergic to local anesthetics, or if you have a bleeding disorder. Your healthcare provider will assess whether the block is appropriate for your situation.

The most common practical limitation is the baby's position. If the baby has descended very low in the birth canal and is close to being born, there may not be enough room to safely insert the needle and administer the injection. In these cases, delivery may be imminent anyway, and other options like local infiltration can be used if needed.

Local infection at the proposed injection site is a contraindication because introducing a needle through infected tissue could spread the infection deeper. This situation is uncommon, but if there's an obvious infection or abscess in the vaginal or perineal area, alternative pain relief methods would be used.

True allergy to local anesthetics would prevent use of pudendal block. However, as mentioned earlier, true allergy to amide local anesthetics is extremely rare. Many people who believe they're allergic actually experienced other side effects (like rapid heart rate from epinephrine) rather than true allergic reactions. If there's any question, allergy testing can be performed.

Relative Contraindications

Bleeding disorders or anticoagulant medications increase the risk of bleeding complications from the injection. The pudendal area has a rich blood supply, and there's inherent risk of needle damage to blood vessels. If you have a clotting disorder or take blood thinners, your healthcare provider will weigh the risks and benefits of the procedure.

Certain anatomical variations might make pudendal block technically difficult. If the ischial spines are hard to palpate due to body habitus or anatomical differences, the provider may not be able to accurately target the injection. In these cases, alternative methods might be preferred.

Patient preference is always respected. Some women prefer to experience delivery without regional anesthesia, or may have philosophical objections to the procedure. Your wishes regarding pain relief should be discussed with your healthcare team in advance as part of your birth plan.

Being Involved in Your Care Decisions

You have the right to be fully informed about your pain relief options and to participate in decisions about your care. Ask questions about the benefits and risks of pudendal block, discuss alternatives, and express your preferences. Your healthcare team should provide clear information to help you make informed choices.

Understanding your pain relief options before labor begins can help you make better decisions during the intense experience of childbirth. Consider discussing pudendal block and other options with your healthcare provider during prenatal visits. Learn what's available at your chosen birth location and what circumstances might make one method preferable over another.

During labor, your healthcare team should explain any proposed interventions, including pain relief, and obtain your consent before proceeding. You should understand why a pudendal block is being recommended, what the alternatives are, and what to expect from the procedure. Don't hesitate to ask questions or request more information.

If you have difficulty understanding medical information due to language barriers, stress, or other factors, support is available. Interpretation services can help ensure you understand what's being discussed. Having a support person present who knows your preferences can also help advocate for you during labor.

Your comfort and preferences matter. While healthcare providers will recommend options they believe are best for your situation, the final decision about pain relief methods rests with you. A good healthcare team will work with you to find an approach that balances effective pain management with your personal values and goals for your birth experience.