BEFORE PHOTOGRAPH: This is a frontal view of a 21 year old woman with a BMI of 25.5 before she underwent lipoabdominoplasty, liposuction of the anterior flanks and hernia repair.
How a woman's skin is going to respond to the stretching effects of pregnancy is both variable and unpredictable. In this relatively young woman's case, her skin developed a number of stretch marks and didn't shrink down to her new body contour after pregnancy.
Liposuction alone in such an individual would probably result in an even less optimal abdominal appearance. The only way to treat a situation such as this is to remove the extra skin, which was done in her case.