Prenatal massage is therapeutic bodywork which focuses on the special needs of the mother-to-be as her body goes through the dramatic changes of pregnancy. Just as mom and baby share the constantly changing pregnant body, they can also share the therapeutic benefits of massage.

Shifts in the center of gravity, may result in tension and pain to the neck, low-back and hips. Massage therapy enhances the function of muscles and joints, improves circulation and can reduce swelling.

But many of massage's most powerful effects come with the relief it brings from anxiety, stress and depression caused by pregnancy's hormonal changes. Reducing anxiety and stress also helps prevent complications associated with pregnancy. "Studies have shown that women with high levels of anxiety and stress have more complications, such as nausea and vomiting, longer labors, spontaneous abortions, postpartum complications, maternal illness and toxemia."
http://pregnancytoday.com/reference/articles/prenatalmassage.htm