Epidurals and other medications to relieve labor pain

An epidural involves injecting medications through a thin tube ( catheter) into a part of the lumbar spine in the lower back, called the epidural space. These medications stop pain signals from being sent from the spinal cord to the brain. Once in place, you feel no pain – or hardly any pain – in your lower body. But you remain awake and fully aware of what is happening.

The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The medication that is injected into the epidural space through the catheter numbs the spinal nerves to block the pain.

The pain-relieving effect is typically felt about 10 to 20 minutes later.

After using a local anesthetic, a small catheter is inserted into the epidural space near the lumbar spine. It is held in place with a sticky patch to stop it from moving.

The catheter is attached to a small pump that is used to deliver the medication continuously. The dose of the anesthetic is usually increased gradually to avoid injecting too much at once. Sometimes there is a patient-controlled pump. This means that you can give yourself more medication if the pain gets worse. If needed, the doctors can also manually give you the medication through the catheter.

A small tube (cannula) is usually put into your arm as well, so that a drip can be attached to it. This is a safety precaution in case your blood pressure drops. Then you can be given the right kind of medication to correct it through the cannula.

Epidurals are very effective and almost always relieve pain better than other medications do. Most women who have an epidural feel little or no pain. Research has found the following:

• About 75 out of 100 women who had an epidural were very satisfied with the pain relief.
• In comparison, 50 out of 100 women were very satisfied with the pain relief from opioids.

Only 1 out of 100 women who had an epidural needed additional painkillers during labor.

An epidural can be used to deliver various types of anesthetic, which also differ in the side effects that they cause. The anesthetist will explain things in detail beforehand.

The common, usually temporary, side effects observed in research included:

• Low blood pressure: In about 13 out of 100 women, the epidural caused blood pressure to drop, which can lead to dizziness or nausea.
• Fever: Epidurals caused fever in about 15 out of 100 women. By comparison, fever occurred in only about 6 out of 100 women who were given another type of pain treatment.
• Problems urinating: About 18 out of 100 women had problems urinating (peeing) because of the numbness in their lower body. A catheter is then sometimes used to release the urine from the bladder.
• Itching: About 3 out of 100 women experienced this side effect.

If the injection goes too deep, it might make a hole in the protective layers around the spinal cord, and spinal fluid can leak out. If too much fluid is lost, it can cause severe headaches that may last up to a few days. This happens in about 1 out of 100 women who have an epidural.

Some women are worried that epidurals might cause long-lasting back pain. But current research has shown that there’s no difference between epidurals and other pain-relief medication here: Back pain was not more common after having an epidural. Permanent damage from injuries to the spine or inflammation resulting from the procedure are extremely rare.

Some women can’t have an epidural – for instance, because they have a blood-clotting problem or an allergy to anesthetics.

Any medication that a woman is given during labor enters the child’s body as well, through the umbilical cord. This includes pain-relieving drugs used for epidurals. Epidurals aren’t associated with any known special risks or long-term negative effects for the child.

But an epidural can influence how the birth goes:

• Length of the birth: Births using epidurals typically last a bit longer – possibly because some children then take longer to turn into the right position for birthing.
• Need for a vacuum or forceps delivery: Women who have an epidural are somewhat more likely to need an assisted delivery using a suction cup or forceps. Then an episiotomy (cut made at the back of the vagina) is usually needed as well, and that has to be sewn afterwards.
• Urge to push: Many women don't feel when or how they should push because of the epidural. The midwife or doctor will then have to tell you when to start pushing.

Epidurals do not increase the chances of needing a Cesarean section. If you need to have one, though, the epidural remains in place and can then simply be used with a higher dose of medication.

The dose used with an epidural is usually low enough that you can get up and walk around. Depending on the exact dose, your legs might feel numb and weak, and you might temporarily not be able to stand up or feel unsteady on your feet.

If a Cesarean section is needed, the dose is increased. Then the entire lower half of your body is completely numb and you can’t move your legs for some time.

Spinal anesthesia (also known as a spinal block) works in a similar way to epidurals, but the anesthetic is injected even closer to the spinal cord: into an area called the subarachnoid space. This causes the entire lower half of the body to feel numb. Unlike an epidural, no catheter is used, so anesthetic drugs can't be added later.

Spinal anesthesia has a faster effect than an epidural. For this reason, it's used if a Cesarean section needs to be done after the birthing process has begun but it's too late to start an epidural.

It is also possible to combine a spinal block and an epidural. Then the pain relief is faster than if the epidural is used on its own. The combination is more likely to cause itching and nausea, though.

Something known as a pudendal nerve block can be performed during the last phase of labor. This involves injecting an anesthetic into the vaginal and perineal tissue (the tissue between the vagina and the anus). But this is usually only done if the birth isn't progressing properly, and the child needs to be delivered with the help of a suction cup or forceps.

Painkillers can also be injected directly into the bloodstream or inhaled (breathed in). These affect the woman’s whole body, not just her lower body. One advantage over an epidural is that a catheter isn't needed. But these painkillers aren't as reliable as epidurals, and some also have more side effects.

Opioids can be injected into muscle tissue or “dripped” into the bloodstream using an infusion (a drip). Some women are given a PCA (patient-controlled analgesia) pump that allows them to give themselves a dose if needed.

Although opioids don't relieve pain as effectively as epidurals do, they can help in some women. But studies show that as many as two thirds of women who are given opioids still have moderate to severe pain one or two hours later. Possible side effects include a drop in blood pressure, nausea, vomiting and drowsiness. The higher the dose, the greater the risk of side effects.

Opioids can also affect the baby’s breathing after birth. Then the baby may be given a drug called an opioid antagonist to counteract this effect. Sometimes the mother is given this drug too. But opioid antagonists not only reduce the side effects of the opioid; they reduce the pain-relieving effects as well.

Painkillers can also be breathed in (inhaled) through a mask. Laughing gas (nitrous oxide) may be used for this purpose. Although this approach is still common in some countries, it is very rarely used in Germany and other countries nowadays because it's not as reliable as other pain-relieving drugs. One advantage, though, is that women can regulate how much of it they breathe in. Laughing gas has a rapid effect, but it also wears off quickly.

It may cause nausea, vomiting, drowsiness or dizziness. There are no known side effects for the baby.

Other medications like acetaminophen (paracetamol), non-steroidal anti-inflammatory drugs (NSAIDs) or sedatives are rarely used to treat labor pain. Compared with the other available options, they aren't very effective.