For any Mom considering Plastic Surgery such as a "mommy makeover", I always advise women to achieve their weight loss goals prior to seriously considering surgery.
You should have lost as much weight as you feel is reasonably realistic, be physically fit, and have healthy nutrition as part of your lifestyle.
There should also be "calmness" in your personal and/or professional life. Chaos is never a good fit with surgery!
Most Moms seek a full abdominoplasty (tummy tuck), which removes excess lower abdominal skin and fat (including some stretch marks!), tightens the muscles of the abdominal wall back together, and decreases the waist line. Sometimes liposuction of the flanks and/or upper abdomen are added to the procedure, if needed.
For women who have not yet reached their ideal weight but who have a large overhang of skin and fat (a "pannus") in their lower abdominal region, it is possible as an interim procedure, to do a limited "panniculectomy". This will only remove the overhang but will not address the abdominal muscles or the upper abdomen.
Be sure to visit a Board-Certified Plastic Surgeon with a great deal of experience in these types of procedures!