Medications for Pain Relief

By OBOS Pregnancy & Birth Contributors | October 15, 2011

Pain medications can be extremely helpful at certain times and in certain situations in labor. They can dramatically ease the pain of labor and can be vital in managing complicated or difficult labors. Yet, like most medical interventions, they have some risks for mothers and babies and should be used only with full knowledge of all options and alternatives as well as of the risks and benefits.

Medications do not take the place of emotional support, encouragement, and comfort measures, which are essential regardless of whether you are using medication or not (see Non-medication Coping Strategies). These medications are not available at outside-of-hospital births; if you are giving birth at home or in a freestanding birth clinic, you will have to transfer to a hospital if at some point you need or want them.

There are two basic ways that pain medications are used during labor: systemically, that is, affecting the entire body, and regionally, affecting a targeted area. The systemic medications are usually opioids (also known as narcotics), but they also include nitrous oxide. Epidurals use a mixture of local anesthetic (numbing medicine) and usually add an opioid.

Systemic Medications

Injectable or Intravenous Opioids

Opioids (also called narcotics) are the most commonly used systemic medicines given to relieve pain during labor. They include morphine (usually used only in early labor to help women get some sleep when this stage of labor is long), meperidine (Demerol or Pethidine), nalbuphine (Nubain), butorphanol (Stadol), and fentanyl (Sublimaze). Specific medicines used vary by provider and location.

When used systemically, opioids are given through an intravenous line (IV) or by an injection into your arm, leg, or buttock. They work by being absorbed into the bloodstream and going to the receptors in your body that diminish pain perception. In general, they make you feel relaxed, sleepy, and possibly a little dizzy, and you tend to feel your contractions less. They may make it easier for you to rest for longer periods of time between the contractions.

Each opioid works for only a limited length of time and can be safely given only at certain times during labor. After a peak of effectiveness, the medicine begins to wear off. The length of time varies from one medicine to another. One to two hours is common, with the peak often being less than half an hour after the medicine is given.

Advantages and Disadvantages of Opioids

One advantage of systemic medicines is that they are short-acting. They therefore can be used at a time in the labor when you just need some help to make it through a challenge. The use of morphine for women who are exhausted in early labor is one example. Another common example is a one time dose of systemic medicine if you are in the middle of labor and feel exhausted or like giving up; it may be what you need to get through this short but tough time. Mothers who try this may get a second wind and do fine without further medication. Others may have an even harder time coping with labor because of the way the medication makes them feel (“high” or disoriented). Another advantage of using systemic medicine over regional medicine such as an epidural is that you can either avoid the possible adverse effects of the epidural altogether or delay getting the epidural until later in the labor, which may diminish the impact of some of the epidural’s negative effects.

The main disadvantage of systemic opioids (narcotics) is that their use in labor has generally been found to have limited effect on controlling women’s pain. They are also much less effective for pain relief than epidurals. They will not take the pain away completely. The medicine may “knock you out” between contractions, or it may “take the edge off” by decreasing the intensity of the contraction at its strongest. Some women experience a welcome feeling of relaxation; others feel a bit out of control.

Other disadvantages of opioids are:

  • The use of these medicines may decrease the production of your own endorphins (hormones that reduce your perception of pain).
  • They are short-acting, and there is a time limit for when you can get another dose. So after you have been given one dose, there is usually a waiting period before you can have more if the first dose doesn’t work as well as you want. Some women find this waiting period very difficult.
  • Just as they circulate throughout your body, systemic medicines get into the baby’s circulation. There, they have the same effect on the baby that they do on you. If a baby is born too soon after this type of drug is given to the mother, she or he may need help to breathe or may have to be given medication to wake up. For this reason, many care providers will not give systemic pain medication if birth is likely to occur soon.
  • Babies of mothers who receive these medicines can also have trouble initiating breast-feeding successfully and may not be able to suck correctly during the first few hours or days of life.

Nitrous oxide (N2O) is an odorless, tasteless gas that you inhale through a mask. You may know nitrous oxide as “laughing gas” or a tool for pain relief during dental care. Exactly how nitrous oxide works is not well understood, but many women who use it during labor find it beneficial. In the United Kingdom, where midwives use it in hospitals and carry it with them to home births, N2O is the most commonly used form of analgesia, with three of every five women using it at some time during labor.

Used with current equipment and procedures, nitrous oxide is safe, is effective for many women, and has important advantages compared to other much more commonly used methods of labor analgesia. It provides better pain relief than opioid medicines and doesn’t have any of the adverse side effects for mothers or babies that can occur after using opioids or epidurals. N2O takes effect very quickly (about a minute after breathing in the gas), wears off quickly, and is controlled by the laboring woman.

Unfortunately, nitrous oxide is rarely available for use in labor in the United States. In 2010, the American College of Nurse-Midwives issued a position statement calling for an increase in the availability of nitrous oxide for laboring women. A growing number of advocates and care providers are working to make nitrous oxide widely available to birthing women in the United States.

Reginal Medications

Epidurals and Spinals

Epidurals and spinals cause numbness below the level of the back at which they are placed. In an epidural, medicine is infused just outside the outermost of the two membranes covering the spinal cord (the epidural space); in a spinal, the medicine is injected between the two membranes. Either epidurals or combined spinal-epidurals are offered for labor pain. These methods may involve the use of local anesthesia, which works by taking away sensation through a numbing effect on nerves. Or it may involve opioid medications only or a combination of local anesthesia and opioid medications.

To place an epidural or spinal, an anesthesiologist or nurse-anesthetist first numbs a small area of skin on your back. For an epidural, she or he uses a needle to place a catheter (a tiny, flexible plastic tube) into the epidural space. With the catheter in place, an anesthetic, or more usually a combination of anesthetic and opioid, can be infused through a pump that controls the dose and the rate throughout your labor. In patient-controlled epidural anesthesia, you have access to a button that activates the pump. (It has controls that won’t allow you to overdose yourself.)

A spinal is a single injection usually used for short-term pain relief in situations when pain control is needed faster. A spinal uses local anesthetic and sometimes an opioid that is injected into the spinal fluid that surrounds the spinal cord. Loss of feeling below the site of injection occurs quite quickly. Spinals are often used for cesarean surgery and sometimes for forceps or vacuum extraction deliveries.

Some hospitals offer a combined spinal-epidural: a one time dose of opioid or anesthetic is injected into the woman’s spinal fluid, and then a catheter is left in place in the epidural space for use when the spinal medicine wears off. The advantage of the combined spinal-epidural is that the spinal component offers relief without numbing, and if relief wears off before the birth, the anesthesia staff can add anesthetics to the epidural catheter and avoid a second procedure.

An epidural or a spinal will be accompanied by continuous electronic fetal monitoring of the baby. In addition, women who have an epidural or spinal will have an IV and equipment to monitor blood pressure. Most women will need a temporary urinary catheter to empty the bladder and will be confined to bed, because this type of medication also affects the nerves that control the hip and leg muscles.

Advantages and Disadvantages of Epidurals and Spinals

The greatest advantage of epidurals (and spinals) is that they can take away the greater part of the pain in labor and while giving birth for most women who use them. An epidural can provide much-needed rest for an exhausted mother, especially when other approaches have failed. An epidural can be helpful in the case of a very long labor. Psychological issues or individual circumstances may make experiencing the physical sensations of labor too difficult for some mothers at some point. Finally, some women choose epidurals simply to eliminate all labor pain.

However, regional analgesia can change the course of labor in many adverse ways. The disadvantages of regional medications used for labor pain include:

  • Sometimes the insertion of the epidural is ineffective, and the process has to be repeated. Epidurals sometimes fail to work or fail to relieve pain in a small area of your abdomen or back (also known as an epidural window). Such areas sometimes can be anesthetized with higher doses of medication but some women never do get complete pain relief.
  • You are more likely to have a short episode of low blood pressure right after the epidural or spinal is injected, which may be associated with a drop in the baby’s heart rate. If this happens, your providers will increase fluids through the IV, help you change position, or administer medicine to raise your blood pressure. If the drop in the baby’s heart rate lasts for more than a few minutes, your provider will likely give you oxygen and may place an internal monitor (which involves breaking your membranes, if they are not already broken) to better track the baby’s response. These episodes of low blood pressure usually resolve quickly and do not cause any lasting effect on you or the baby.
  • Spinal and epidural opioids can cause itching. This is generally mild but can be quite bothersome for some women.
  • This type of medication can increase the amount of time that you are in labor, including a longer pushing phase.
  • You may be more likely to receive Pitocin, a synthetic form of the hormone oxytocin, to make your contractions stronger.
  • The longer you have an epidural, the more likely you are to develop a fever during labor. Because your providers cannot know if a fever is from an infection or from the epidural, if you get a significant fever in labor, your providers will start antibiotics and your baby may be separated from you and subjected to more tests in the first hours after birth.
  • You are more likely to have forceps or vacuum delivery. Instrumental vaginal deliveries are more likely to lead to tears into or through the anal sphincter muscle.
  • Between one and two of every one hundred women who get an epidural, and fewer than one of every one hundred women who receive a labor spinal, get a severe headache called a spinal headache. The headache usually doesn’t start until the next day; if it occurs, effective treatment is available.

Evidence is mixed on whether there is an association between epidurals and problems in establishing breastfeeding; such problems seem more likely to be linked to epidurals that include high-dose opioids in the mixture.