It is normal for newborns to seem to strain when they have a bowel movement. Sometimes their face turns red too.  Having a bowel movement is complicated. One needs to tighten the stomach muscles while relaxing the anal sphincters.  When your baby gets that feeling, he needs to get his whole body involved to figure it out.  As long as the bowel movement is soft when it comes out (not thicker than soft-serve ice cream) then all is OK.   Formula fed babies usually need to go once a day.  Breast fed babies initially go every time they are fed, but over the first few weeks may slow down and even skip several days between bowel movements.