Sciatica is the common name given to a set of symptoms caused by compression and irritation of the sciatic nerves. Excess pressure on any of the five lumbar nerve roots may also lead to the symptoms as they are the origins of the sciatic nerves. Sciatic nerves originate from the lower back region, travelling down the back of the legs before branching out to the feet. They are responsible for the feelings of touch and pain as well as muscle movements in the legs.
One of the most common causes is a slipped disk or a herniated disc (rupture in a spinal disk that causes the gel inside to leak out) due to the additional pressure put by the growing uterus on the sciatic nerves and the spine. However, slipped disk is not the only cause of the condition. During the third trimester, the baby starts shifting into the birth position which may place the baby directly on the nerves leading to severe symptoms of sciatica. 
The signs and symptoms are similar to those caused by pelvic girdle pain during pregnancy. However, those associated with sciatica are usually more severe, affecting just one side of the body. The similarity of the symptoms often leads pregnant women to believe they are suffering from sciatica when in reality they have pelvic girdle pain.  The common symptoms usually include:
In most cases, there are no preventive measures for the symptoms. But, women in the habit of regular exercising throughout their lives are less prone to this nervous damage during their pregnancy. Regular exercise helps to maintain healthy muscle tones, enabling them to better support the weight of the uterus. Avoiding overeating prior to conception and during the early stages of pregnancy (first trimester) may also help.
It does not usually require any diagnostic tests as the symptoms are enough for the doctors to identify the condition. However, imaging tests like MRI may be necessary in case it affects the functioning of the sciatic nerves.
The main object of treatment is to reduce the pressure on the sciatic nerves that helps to deal with the symptoms.
Doing regular stretches and exercises can help to manage the pain by strengthening the spine, stomach muscles, hips, pelvic floor and back. In case of persistent sciatica, one needs to continue the exercises even after the baby is born. The pain may refuse to go away for months after delivery, with following a proper exercise routine being the most effective remedy. Exercises generally recommended during pregnancy include:
It is important to consult an expert before practicing any of the above exercises.
In most cases, the symptoms subside within six weeks, while some may take around 12 weeks to recover completely. For some women, mild symptoms may persist for about 6 months after delivery, causing temporary disability.
The ICD-9 code for Sciatica is 724.3 while its ICD-10 code is M54.3 -M54.4