The abdominal wall is made up of three main structures from a practical point of view; the muscle or strength layer, the fatty layer and the skin. Each of these layers are affected and impacted differently in each pregnancy. The skin and muscle have an incredible ability to stretch. Skin is not a supportive structure but a veneer. It will gradually expand when placed under continuous pressure to accommodate the developing baby. The ability of the skin to tighten after a pregnancy is dependent on many factors such as genetics, amount of weight gained during the pregnancy and what number pregnancy it is. You are more like to achieve your pre baby tummy with the first pregnancy than the third.
We have all blown up a balloon and let the air out noticing the balloon returned to its original shape, by the third time the deflated balloon is clearly stretched and unable to return to its original form. Stretch marks can also form during the pregnancy when the tensile strength of the skin is exceeded. The skin is intact but the dermal layer has been stretched beyond repair. There is a difference in the thickness of skin in these areas, which creates the contouring irregularities, and color change we commonly see.
As the baby grows the abdominal muscles, which are together in the midline are separated. There is a strength layer investing the muscles so hernias usually do not develop but it is this fascial layer that does not return to its original tightness. You can exercise all you want, the muscles will be strong but they will not be in the optimal position. You can check this by putting your ankles together and raising them about 6 inches off the ground. If you see a dome like fullness above the belly button you have what is called a rectus diastasis. This is not symptomatic or dangerous but a flatter tummy can only be corrected with surgery when this condition persists.
Lastly, the fatty layer we are all too familiar with will vary depending on the amount of weight gained. The fat stores acquired can be diminished with appropriate diet and exercise in the postpartum period. But remember it took 10 months to put the weight on so give yourself time to get it back off.
Supporting your postpartum tummy can be achieved with the use of proper postparutm support garments, designed specifically for the postpartum period. As used successfully in a variety of body contouring procedures to facilitate healing, mothers may also benefit greatly from the use of compressive support garments during the postpartum healing and recovery periods, both in the short term immediately following childbirth, and again in the later stages where body shape is a concern.