You’re in your eighth month of pregnancy and all keep saying to fully enjoy these oh so magical and wonderful last moments of pregnancy. But for you, these moments have nothing to do with magic and wonder. You feel like you weigh a ton, that your pelvis wants to split in two to let baby through. The pain in your low back down and your buttocks leave you with little rest; it even goes down into your calf. What’s going on? What to do?
Sciatica, a condition that results in pain in the path of the sciatic nerve, is one of the most common physical ailments of pregnancy1. It can occur at any time during pregnancy, but it is more common in the last trimester.
The sciatic nerve is the largest and longest nerve in the human body and we have one on each side of the body. It consists of the nerve roots of the lower lumbar region and sacrum (L4, L5, S1, S2, and S3) which meet in the buttock before descending along the rear part of the thigh and on the side of the leg to the ankle.
Sciatica is an irritation of this nerve which can cause pain in any of those parts. Several causes can lead to an irritation of the sciatic nerve: a herniated disc, joint inflammation of the last lumbar vertebrae, an imbalance of the pelvic joints, muscle spasms, etc. However, during pregnancy, several cases of sciatica are caused by the sacroiliac joints (those that unite the bones of the pelvis to the spine) and the muscles that support them.
During pregnancy, the body secretes a hormone called relaxin, which aims to increase the elasticity of the joints to prepare the pelvis to widen during the passage of the baby during delivery. This release, combined with the increased weight of the baby, promotes stretching of the sacroiliac joints. This distension may be asymmetric and incidentally, it can cause an imbalance of the joints. The side where the joint is stretched more is most likely to cause inflammation, which can cause local pain in the buttocks and even widespread pain behind the thigh1.
The muscles that run through the sacroiliac joint, however, contract in order to stabilize it. If muscle tension becomes excessive, the sciatic nerve can be compressed as it is under these muscles2. Nerves being very sensitive to compression, it is usually enough to cause pain throughout the course of the nerve.
In addition, weight gain especially around the belly creates significant postural changes. In particular, the center of gravity is moved forward and lumber lordosis (swayback) is increased. These changes combined with, again, the action of relaxin may promote a decrease of normal mobility of lumbar vertebrae, excessive stretching of the lumbar muscles and ligaments and even cause or exacerbate a herniated disc. All of these situations may cause back pain and create irritation to the sciatic nerve or a nerve root component.
Relief…
To prevent the occurrence of such pain, it is better to avoid wearing high heels during pregnancy and not to sit cross-legged. Your chiropractor will recommend adequate sleep postures; including the use of a cushion to space your knees when you sleep on your side might be suggested.
The chiropractor will perform a chiropractic examination, neurological and orthopedic to determine the indication of care. Then, with treatment, they can help prevent and alleviate this problem by ensuring that the pelvic bones are aligned and promoting a more balanced mobility of the sacroiliac joints, correcting subluxations in the lumbar vertebrae by helping spasmed muscles and stretched ligaments relax. These corrections will aim to restore normal mechanics of the pelvis and lumbar spine and reduce or eliminate factors causing irritation of the sciatic nerve1,3.
When the sciatic nerve is acting up, one must however be patient. While chiropractic is often very effective in relieving sciatic pain, it is often recurrent, which may require regular monitoring to prevent its recurrence or relieve recurrence.
References:
- Fallon, Joan, Orthopedic and neurological conditions of pregnancy and chiropractic management of care, ICA review, jan/feb 1993.
- Jonathan S. Kirschner, Patrick M. Foye et Jeffrey L. Cole,« Piriformis syndrome, diagnosis and treatment», in Muscle & Nerve, vol. 40, no 1, 2009, p. 10-18
- Lisi, Anthony J.,Chiropractic spinal manipulation for low back pain of pregnancy: a retrospective case series, Journal of midwifery & women’s health, vol 51, no 1, 2006.
