Nine months full of hopes and projects: for mothers expecting a baby, the period of pregnancy is particularly intense and full of emotions, but it is also tiring. Choose the best pregnancy pillow for stomach sleepers. The continuous physical transformations and the weight of the growing baby are the main reasons why expectant mothers often feel sleepy and feel the need for a little rest. Finding the right position is, however, a challenge, especially when the belly starts to grow. Experts recommend lying on the left side.