Most cases of carpal tunnel syndrome are caused by a combination of factors. Studies show that women and older people are more likely to develop the condition. Other risk factors for carpal tunnel syndrome include: Heredity. This is likely an important factor. The carpal tunnel may be naturally smaller in some people, or there may be anatomic differences that change the amount of space for the nerve — and these traits can run in families. Repetitive hand use. Repeating the same hand and wrist motions or activities over a prolonged period of time may aggravate the tendons in the wrist, causing swelling that puts pressure on the nerve. Hand and wrist position. Doing activities that involve extreme flexion or extension of the hand and wrist for a prolonged period of time can increase pressure on the nerve. Pregnancy. Hormonal changes during pregnancy can cause swelling that results in pressure on the nerve. Health conditions. Diabetes, rheumatoid arthritis, and thyroid gland imbalance are conditions that are associated with carpal tunnel syndrome.