The epidural demonstrated its efficiency a long time ago in relieving labor and delivery pain. This undeniable relief is also very popular for women in labor. In Quebec, nearly 70% of all women giving birth demand the injection. It is the highest rate in Canada.
With the epidural, the contractions are sometimes felt as a mere pressure on the abdomen.
What is the epidural?
First, let’s take a look at the point of injection. It is located in the spinal cord where the nerve roots (spinal nerves) relaying pain messages from the uterus to the brain are attached. The spine bathes in cerebrospinal fluid, inside the dura mater (the membrane that protects the spinal cord).
During the perfusion, the needle is inserted into the epidural space (epi=around, around dura mater). The medication is then injected through a catheter attached to the needle. The effect is felt after 15 to 20 minutes and lasts until delivery through a continuous perfusion of the drug in the catheter.
The liquid painkiller that subsequently diffuses in the epidural space is composed of a local anaesthetic (similar to the one used by the dentist) and a narcotic. “This narcotic increases the analgesic potential to eliminate or reduce pain” says Dr Christian Loubert, anaesthesiologist at the Maisonneuve-Rosemont Hospital. The local anaesthetic, however, doesn’t only inhibit the pain signal transmission; it also disrupts the motor functions of the nerve. A higher dose can cause partial paralysis of the lower body. For this reason, anaesthesiologists have substantially reduced the dose over the past ten years, says Dr. Loubert.
The risks
- Several studies have shown a link between the epidural and a higher rate of C-sections but other studies have shown otherwise. According to Dr. Loubert, the absence of a link between the two is commonly accepted among the scientific community.
- The epidural would also interfere with some labor and delivery hormones, some of which induce the final and powerful contractions, the ones that would enhance the bond between the mother and her baby.
- The epidural would also affect the action of adrenaline and noradrenaline that give the energy to push the baby out.
- The Maisonneuve-Rosemont anaesthesiologist tones down these conclusions. While admitting that the epidural can slow down the two first stages of labor, he argues that we should rather wonder if it harms the mother or the baby and it is not the case.
- Other studies have also shown that the epidural numbs the pelvic floor muscles that, among other things, guide the baby’s head in the right position to come out. The baby would be four times more likely to present as breech in the last stages of labor. According to Dr. Loubert, this risk is very low since the epidurals are made with reduced concentrations of anaesthetics, preserving the pelvic floor tone.
- The paralysis that can occur when the needle penetrates a blood vessel – for example when a patient suffers from clotting problems – only happens in very rare cases.
- It is also possible – in about one woman in 100 – that the needle pierces the dura mater. The cerebrospinal fluid escapes and spreads in the brain. Because the brain doesn’t “float” any longer, the gravity pulls it downward, causing headaches that can last up to one week.
- About half of all women using the epidural experience a slight decrease of blood pressure and they are five times as likely to present with a fever of more than 38 degrees.
- They are also twice as likely to bleed after delivery and two women out of three can experience difficulties to urinate and suffer from an itchy skin.
