The left hand is always numb in pregnancy, which may be related to the following reasons: 1. It may be caused by cervical spondylosis, many pregnant women are used to sitting and standing for a long time during pregnancy, or playing with cell phones for a long time, so that the physiological curvature of the cervical spine gradually changes, straightens or even produces an anti-arch. At this time, if neurogenic cervical spondylosis occurs, it may produce a series of symptoms such as radioactive pain, numbness and weakness in one of the upper limbs. 2. It may be caused by the compression of peripheral nerves, for example, during pregnancy, if the patient often uses the left hand to support the ground or the left elbow joint to support the table, it may cause some peripheral nerves, such as the median nerve or ulnar nerve, to be compressed, and some areas of the left hand may become numb. 3. It may be caused by vascular-related lesions, such as cold or lack of activity, which may cause the small blood vessels in the left hand to contract, resulting in poor blood circulation and making the patient feel numb.