The carpal tunnel is formed by the wrist bones and a ligament that stretches across these at the front of the wrist. A major nerve to the hand, called the median nerve, passes through the carpal tunnel at the wrist.
Carpal tunnel syndrome occurs when the nerve is compressed. It is characterised by numbness in the thumb, index and middle fingers. In more severe cases it can cause pain, and later, weakness in the thumb.
About 7% of pregnant women will experience carpal tunnel syndrome. It is due to increased fluid retention and hormonal changes in pregnancy, and so, it is more common in the second half of pregnancy and in warmer months. Women often wake with burning, numbness, and tingling in the hand and report shaking the hand to relieve the discomfort. In 75% of women it affects both wrists.
In the non-pregnant woman, corticosteroid injections and surgery are the common methods of treatment as the condition does not normally go away. In pregnancy, conservative treatments are used as the condition tends to resolve after delivery over a period of weeks to months. Symptoms may recur in subsequent pregnancies.
Pressures within the carpal tunnel are least when the wrist is in a neutral position and greatest when the wrist is bent forward or backward. When we sleep, our wrists tend to bend and this is why carpal tunnel syndrome tends to wake women at night.
The mainstay of treatment is to splint the wrist or wrists in a neutral position at night. This allows women to have a good night’s sleep. If women are affected by carpal tunnel syndrome during the day, they can wear the splints day and night.