Sciatica in pregnancy- symptoms & causes

True sciatica is rare in pregnancy with some studies only showing 1% of pregnant women experiencing posterior pelvic pain having sciatica. Sciatica is a term that describes a set of neurologic symptoms associated with irritation and/or compression of the nerve roots that eventually form the sciatic nerve or sciatic nerve proper. There are many different causes for irritation or compression of the sciatic nerve.  As there are many differing causes of sciatica, with a range of differing symptoms and intensities. In the child bearing age group the two most common causes of true sciatica are piriformis syndrome  and a disc prolapse. Most commonly women who think that they have sciatica have one of the pelvic girdle pain in pregnancy conditions.

Primary Symptoms of sciatica in pregnancy

• The primary symptoms are all neurological or nerve based due to the compression on the sciatic nerve or nerve roots, one or more of these symptoms need to be present in order for the diagnosis to be sciatica.
• Pain that starts in the low back or buttock, and radiates down the thigh and typically into the lower leg and/or the foot.
• The pain experienced tends to be a sharp pain, as opposed to a throbbing or dull ache. Words people often use to describe sciatic nerve pain include burning, searing, sharp pain.
• In addition to pain, other common symptoms include heaviness, tingling, pins and needles, numbness and weakness in the thigh, leg or foot.
• Pain levels can range from dull to extreme.

Secondary symptoms of sciatica in pregnancy

• Decrease in reflexes may be picked up by your Doctor or therapist.
• Symptoms typically only occur in one leg.
• Difficulty is walking due to foot drop caused by neurologic weakness.
• In extreme cases loss/change in bladder and bowel control.
• Acute muscle spasms/cramps.

Please ensure that you speak to your GP, Obstetrician, midwife or other therapist if you are experiencing any of these symptoms.

What is happening and why

The sciatic nerve is the biggest nerve in the body. It is formed by lumber nerve roots L4 and L5 and the sacral nerve roots S1, S2, S3 off the spinal cord. These roots then join together at the level of the piriformis muscle in the pelvis to form the sciatic nerve. The nerve then travels into the leg and divides into further to supply the lower leg and feet.

Sciatica is a term that describes a set of neurologic symptoms associated with irritation and/or compression of the nerve roots or sciatic nerve proper. Sciatica proper is a radicular pain or radiculopathy. This is when pain is experienced in the dermatome or region of the body that the particular nerve supplies. Most commonly it is the L4 or L5 nerve root that is affected as a disc bulge or prolapse is the most common cause of sciatica.

The L4 dermatome or area that the symptoms may be experienced is shown on the left side image. In the anterior and lateral aspect of the thigh, medial to the knee, the medial aspect of the leg and the medial aspect of the foot.

The L5 dermatome is the most commonly effected and is shown on the right image. Symptoms are experienced in the centre of the buttock, down the posterior aspect of the thigh, the lateral and posterior aspect of the leg, the top of the foot and under the big toe. As everyone is slightly different, take these images as a general guide, you may not experience symptoms with this exact distribution.

The two most common causes for sciatica are a disc bulge and piriformis syndrome as other causes are more serious or unlikely to occur in the child bearing age group such as spinal canal stenosis, spondylolisthises, degeneration or arthritis.

If you have had a history of low back pain, it may be beneficial to:

• Do some rehabilitation with a physiotherapist, pilates instructor or personal trainer to ensure that your core, lumbar and pelvic musculature is strong and functioning as best as possible prior to getting pregnant.
• Get treatment from your chiropractor, osteopath, myotherapist, acupuncturist or physiotherapist to ensure your pelvis and low back are in good working order before trying to get pregnant.
• Act as soon as you start to experience symptoms they tend to worsen as the pregnancy progresses.
• It has been suggested that having a 2 year gap between pregnancies enables the body to recover and decreases the chance of re-occurrence.
• Studies have shown that Women who are physically fit have a lower risk of getting lumbar pain in pregnancy.