“Okay, on your next contraction you are going to pull your legs as far up as you can, while I push down on your cervix to push the sacrum out of the way, and you push as hard as you can.”
It had been 20 hours of labor. I had an epidural placed when fully dilated with a cervical lip. There was an hour of pushing, a dropping fetal heart rate, and a baby stuck in the birth canal. I was laying on my back with Shawn holding one leg, the nurse or myself holding the other. I was completely numb below the waist from the epidural. So many factors in this scenario contributed to my femoral nerve damage. As a physical therapist, naturally I wanted to figure out why this happened.
Nerve Damage from Giving Birth
It’s a common misconception that those who suffer from numbness and weakness after giving birth had an epidural complication. That was the first assumption when I was unable to stand up hours after giving birth. “Wow, that was a really strong epidural,” they told me. The anesthesiologist came in to check me out, but the nerve distribution of the femoral nerve did not coincide with the placement of the epidural. Postpartum nerve injuries are reported in 1% of women who have given birth. It’s usually caused by a stretch or compression of the lumbosacral plexus by either positioning of the mother during birth, the fetus’s head compressing the nerve in the pelvis, or the use of instruments during delivery.
The lumbosacral plexus is a branch of nerves located within the pelvis that come off from the spinal cord at the lumbar and sacral levels of the spine. This branch of nerves divides into peripheral nerves that innervate the various muscles of the pelvis, hips and legs. The femoral nerve, which was the source of my injury, passes underneath the inguinal ligament.
In the commonly used Lithotomy position for giving birth, the hips are hyper flexed, abducted and externally rotated. Think frog legs while laying on your back position. This position in particular can cause compression of the femoral nerve by the inguinal ligament for a prolonged pushing phase.
The sacral plexus is located on the back side of the pelvic cavity. It is vulnerable to compression from the fetal head as it descends into the birth canal. It is more common with first time moms, large babies, narrow pelvic canal shape, and forceps delivery. This can cause trauma to multiple nerve segments.
Other Common Nerve Injuries from Birthing
Lateral Femoral Cutaneous Nerve-exits the pelvis through a split in the inguinal ligament. This nerve does not have any motor implications. It’s strictly a sensory nerve. Damage can occur with prolonged time in the traditional lithotomy birthing position. It causes numbness and tingling of the front and outside portion of the thigh.
Obturator Nerve– located in the inner border of the psoas muscle, it passes through the obturator canal on the outer wall of the pelvis. It controls the adductor muscles of the inner thigh. With damage to this nerve, it is difficult to adduct (pull leg in towards midline) with numbness of the inner thigh.
Sciatic nerve– the sciatic nerve is the largest peripheral nerve in the body and is commonly injured due to its superficial location. It passes through or above the piriformis muscle and often can be compressed due to tightness at this muscle. Damage to this nerve causes numbness to the top of the foot or back of the leg, foot drop or difficulty lifting the foot up, and weakness of the hamstrings.
Is My Pelvis Too Small to Give Birth Naturally?
There are four different pelvis shapes. Depending on the type of pelvis you have may determine the success rate of having a vaginal birth. You may have heard that you are too small to deliver a baby measuring large. The size of the person giving birth doesn’t always determine need for caesarean section. The shape of the pelvis rather than overall size of the mother is more likely to cause issues.
The four pelvis shapes are as follows:
Gynecoid- This is the most common pelvic shape in females. It is round, open and shallow and the most ideal shape for giving birth. It gives the most room for the baby to descend into the birth canal.
Android- This pelvis shape is similar to the shape of a male pelvis. It is narrower and shaped like a heart or wedge. This shape can make for a difficult labor because the decreased space for the baby to descend into the birth canal. It is more likely to result in c-section.
Anthropoid- This pelvis shape is narrow and deep similar to an egg that is upright. It has more room front to back in the birth canal, but still more narrow than the Gynecoid. This may result in a longer labor.
Platypelloid– This pelvis is flat, wide and shallow. It is the least common shape and resembles an egg on its side. The baby may have trouble passing through the canal. This shape is more likely to result in nerve damage and has a higher rate of requiring c-section.
Although some pelvis shapes are more likely to result in a difficult childbirth, it doesn’t automatically mean that it will result in a c-section. Other factors, such as baby positioning, carrying multiples, not dilating enough, and how you are positioned to give birth can play a role in determining whether a vaginal birth will be successful.
How Does an Epidural Plays a Role?
Although the epidural itself isn’t the cause of these types of injury, it can play a role. When given an epidural, the body doesn’t have its natural defense mechanism in preventing pain. In the lithotomy position, if the nerves are getting super stretched or compressed, you would normally be able to feel the pain and back off from the position. With an epidural, you are unaware of the nerve compression and continue the course of action without realizing you are further damaging the nerve.
Why is the Lithotomy Position Not Ideal?
The sacrum is the large flat bone at the base of the spine, and the coccyx, commonly called the tailbone, is at the end of it. The coccyx is able to move 16 degrees when giving birth to make space for the baby’s head. When laying on the back for the birthing process, the sacrum is in a fixed position. It has less movement because the bed is there. The coccyx in this position is only allowed about 4 degrees of movement, making the birth canal a lot less spacious.
Researchers have found that by taking the body weight off from the sacrum and coccyx it allows the pelvis to expand more to make room for the baby descending into the birth canal. Positions like hands and knees, kneeling, standing, side lying, and squatting are better at allowing the flexible sacrum to move. It’s been found that birthing in these positions, especially for first time moms, result in a lower rate of caesarean deliveries.
So Why Do Most People Give Birth on Their Backs?
Most healthcare workers prefer patients to give birth in bed on their backs despite this not being the ideal position anatomically. If you are lying in bed, it is easier for them to monitor fetal heart rate, this is often how they are trained in school, and it is easier to catch the baby in this position. A high rate of epidural use has also resulted in more births in this position. Care providers perceive that upright birthing positions are not possible with an epidural, since the person is unable to get into these positions without help.
Why Did This Happen to Me?
After I ended up with this numbness and weakness in my right leg, I questioned why did this happen? I did my research and talked to my doctors and midwives. The conclusion is that multiple factors likely played a role. I had an epidural and could not feel anything below the waist. I was placed in the Lithotomy position in the hospital bed with my legs in the fully flexed and abducted. This likely compressed my femoral nerve. If I didn’t have an epidural, I may have been able to feel the pain in this position and move out of it. I was also pushing for over an hour. That is a lot of time spent in this position.
I don’t know the position of the baby’s head and whether that was a factor, but it’s possible. The bigger issue was my pelvis. The OB had told me that the shape of my pelvis was narrow. My sacrum was tilted downward, allowing for minimal room in the birth canal. I’m not sure the exact shape of my pelvis, but it didn’t sound ideal for birthing. Since it was shaped this way, the OB was on the bed applying force to me internally downward to move the sacrum out of the way. As I now have learned, the lithotomy position doesn’t allow for much give when the sacrum and coccyx is fixed. The manual pushing of the sacrum could have put the already compressed femoral nerve on stretch causing further axonal damage.
Will This Happen to Me Again?
After I recovered from this injury after months of pain and weakness, I questioned whether this would continue to happen to me in subsequent births. It was such a traumatic experience; I was afraid to even think about going through it again. The shape of my pelvis is still the same. How would a future birthing experience be any different?
Now that I know more about the likely cause of my nerve damage, there are a few things that I would do differently. First of all, I would not get in that damn hospital bed to labor. I was told I had to get in the bed before I was even ready to push. It was uncomfortable laboring in the bed. That was part of the reason I gave in to needing an epidural. Speaking of the epidural, I would try to avoid it at all costs. It was what I truly needed in this situation, but I think that not being able to feel below the waist played a role in my nerve damage. Lastly, I would not push in the lithotomy position. If my pelvis is shaped in the way the doctor described, this sounds like the worst position for me.
Could this happen again? Sure. Knowledge is power and I feel more prepared. Will I ever give birth again? I hope so. I would love a redemptive birth. When that time comes, I’m taking back control of my experience.
To read more about my birth story click here: The Beginning
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