According to What to Expect, tingling hands are a common condition during pregnancy. Pregnancy often causes swelling, which pushes on wrist nerves and leads to numbness. In serious cases, the pressure leads to carpal tunnel syndrome.
What to Expect explains that hand tingling and pain are more common when lying down at night, because fluids that have been in the lower body are free to circulate and accumulate in the wrists. To minimize swelling, a pregnant woman should not sleep on her hands. Propping them up at night on pillows helps. During the day, caffeine should be avoided. In addition, the hands and wrists should get frequent breaks to be shaken out and rotated.