Does your belly stick out no matter how hard you try to suck it in? Are sit-ups and crunches more difficult now? This may be because of a combination of abdominal muscle weakness and separation. There are several abdominal muscles affected by pregnancy, but the rectus abdominis muscle takes the hardest hit. It not only thins out and widens, but it also rubberbands and lengthens vertically. It also separates in the midline where the belly button is. As a result, the belly button can look distorted, wrinkled, large, and hollow and the bulge in the lower belly can resemble a three- to four-month pregnant belly. A tummy tuck can repair abdominal muscles, smooth out and tighten skin, and restore the pre-pregnancy appearance of the belly button.