From Web MD:
A pre-natal massage typically lasts an hour. Some practitioners use a pregnancy massage table. That's a table designed to accommodate a woman's pregnant belly. Others use specially designed pillows called bolsters to position a woman comfortably on her side. This helps especially during the later stages of pregnancy. Lying on your side is often the most comfortable position.
Only a handful of small studies have focused on massage in pregnancy. No definite benefits have been established. But one study at the University of Miami School of Medicine suggests that massage therapy might have multiple positive effects, including:
In another study of pregnancy massage in depressed women, researchers found:
Research has shown that, for the general population, massage has other potential benefits. It may relieve pain, or it may boost the immune system’s ability to fight off viruses and tumors.