How Does an Epidural Work?

You’ve probably heard of an epidural, which is also called epidural anesthesia. If you’re planning to give birth in the hospital, you will probably have access to an epidural during your labor if you choose it for pain relief. Many people who give birth in the hospital take advantage of epidurals, but what are they and how do they work? In this post, we’ll discuss how epidurals work, the pros and cons, and what actually happens when you request one.

How epidurals work

Epidurals are anesthesia that numbs your body from your belly button to your legs, which can provide pain relief to the abdomen and back during labor. To place an epidural, an anesthesiologist or nurse anesthetist inserts a needle into the space around your spinal nerves—known as the epidural space—and then threads catheter (a slim, flexible plastic tube) along the needle into that space. The needle is then removed and the plastic tube stays in place, so that medicine can be supplied to your spinal nerves continuously. The medicine blocks the pain signals from traveling from your spinal nerves to your brain.

Medicines usually used for epidurals include a combination of a local anesthetic, such as bupivacaine or ropivacaine, and an opioid like fentanyl. The two medicines work together, providing more rapid effects and using lower drug levels than local anesthetic alone.

Pros and cons

The pros of epidural anesthesia include relief from pain with properly working epidurals, increased alertness compared to other pain relief techniques like intravenous pain medications, and the opportunity to rest. When the pain of labor is so bad that you’re unable to sleep, but are not making progress, an epidural might be a really good idea. Other positives of epidurals include that you can receive an epidural at most points during labor in contrast to IV pain meds, which are not usually given when birth is imminent due to their possible effects on baby’s alertness, and that, if you have an epidural, you likely will not need to be given general anesthesia (which puts you to sleep) for an emergency C-section.

The cons of epidural anesthesia include possible adverse effects—things like shivering, itchiness, fever, and severe headache that can last days after removal. It’s also possible that an epidural will lower your blood pressure beyond what’s advisable for you and baby, at which point you’d need to be treated with a different medication to help increase your blood pressure. And depending upon how dense your epidural is—that is, how strongly it effects you—you may lose feeling of not only pain but also sensations like pressure that help you know when and how to push. Epidurals usually require continuous fetal monitoring, which require you to be hooked up to some kind of monitor that can constantly report baby’s heart rate, and often it’s difficult or impossible to move with an epidural in place. Because movement is one thing that helps labor progress, that means an epidural may slow down your labor. And the lack of movement also means that you’ll have to have a urinary catheter inserted to help drain your bladder, which can be a risk for infection. Finally, many hospital policies do not allow people receiving epidural anesthesia to eat. You can likely still have clear liquids and things like popsicles, but often solid food is discouraged.

What happens when you get an epidural?

If you decide to receive an epidural, you will also likely have an IV put in place if you don’t already have one, usually in your arm or hand. Then the nurse will probably give you what’s called a bolus of IV fluids, which is a large amount of fluid quickly. This bolus helps offset the drop in blood pressure that is likely during an epidural. You’ll also wear a blood pressure cuff and an oxygen monitor (usually in the form of a small sticker worn on your finger) so that your care providers can monitor your heart and lung function while you have the epidural.

Before the anesthesiologist arrives, your nurse will sit you up on the edge of the bed so that you can curl your body around your baby and push your lower back out like a mad cat. This position is one that you should hold throughout the epidural placement as it allows the anesthesiologist to access the epidural space in your back. Holding this position and being still throughout the epidural placement when you’re in the midst of painful contractions can be one of the most difficult things about an epidural.

When the anesthesiologist shows up, she or he will clean your back and place a piece of fabric or plastic, so that the area remains germ free. Then they will inject numbing medicine into your back. This injection can feel like a big bee sting and make your back tingle or burn while the numbing medicine takes effect. Then the anesthesiologist places the epidural catheter and administers a test dose of medication to make sure the catheter is threaded into the correct place and then an initial dose of medicine to help with your labor pain relief. They’ll then put a dressing over the catheter and usually secure it with tape. Then the catheter is connected to a bag of medicine that can continually drip into the catheter and provides ongoing pain relief.

At that point, your nurse will likely encourage you to lay back on the bed with your legs out straight so that the medicine, which is distributed throughout your body by gravity takes effect evenly. Once the initial numbness sets in (usually within 30 minutes), you can change positions or your nurse, birthing partner, and doula can help you change positions to help continue to move the baby down. After birth, your epidural will be turned off and the epidural catheter removed.

Abby Olena
Dr. Abby Olena has a PhD in Biological Sciences from Vanderbilt University. She lives with her husband and children in North Carolina, where she writes about science and parenting, produces a conversational podcast, and teaches prenatal yoga.

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