The stresses on a woman's body during pregnancy are significant and come from a variety of sources. Hormones cause the body and mind to function differently than normal in preparing the body for the rigors of bringing a baby to term and caring for a newborn. Women also experience physical changes due to a growing baby, as well as physical stress from the change in body weight distribution. Taken together, these changes can lead to a variety of symptoms, including numbness of the hands and fingers.
Many processes can produce numbness, but in general, numbness and tingling of the extremities are indications that something is interfering with a nerve's ability to sense and report sensation from the extremity back to the brain. The familiar feeling of a hand or arm having "gone to sleep," for instance, is due to reduced blood flow limiting the ability of nerves in the hand to send signals, explains MayoClinic.com.
Some causes of numb or tingling fingers during pregnancy are due to hormones. In his book, "What You Didn't Think To Ask Your Obstetrician," Dr. Raymond Poliakin notes that the hormone relaxin, released late in pregnancy to enlarge and soften the pelvic opening, causes other joints to relax as well. This can lead to pinched nerves in the shoulders and arms, leading to numbness. Further, early pregnancy hormones cause women to retain water, which may cause the carpal tunnel, or passage through which nerves pass in the wrist, to swell, causing numbness.
It's not just hormones, however, that change a woman's body during pregnancy. As her baby grows, it puts stress on the front of her body and pulls her spine forward at the lower back. This can affect posture and may throw muscles in the back and neck out of their normal alignments, which in turn may affect the neck and shoulders. Notes Dr. Poliakin, pinched nerves and finger numbness can result from postural changes.
While it may be difficult to prevent tingling and numbness in the fingers, there are several drug-free mechanisms for alleviating symptoms during pregnancy. The authors of "What To Expect When You're Expecting," Heidi Murkoff and Sharon Mazel, suggest sleeping with the hands elevated, using a wrist brace, and maintaining adequate hydration during the day to avoid swelling of the wrists and exacerbation of carpal tunnel-related numbness. Exercise and being aware of posture can reduce the symptoms of a pinched nerve.
While mild numbness and tingling in the hands and fingers are normal, it's best to contact a medical practitioner if symptoms become severe, come on suddenly or worsen significantly with time. Dr. Poliakin notes that these may be signs of an injury or other potentially serious condition, warranting a checkup. Further, pregnant women should always discuss medications, both prescription and over-the-counter, with their physicians before using them during pregnancy.