There are many different types of scars that may develop during and after your pregnancy. However, there are essentially two main types of external scars. The first type of pregnancy scar is formed as a result of having a Caesarian section. This scar is often quite large and while the natural regeneration of skin will diminish its appearance over time, it will never completely heal naturally. The other main type of scar that occurs after pregnancy is striae, which is commonly known as stretch marks. This type of scarring occurs when the skin experiences rapid growth such as the expansion ofskin around the abdomen during pregnancy. Stretch marks may also occur the legs, chest, buttocks as well as any other area of the body that experiences a sudden change in size.
If you have external scars as a result of a pregnancy, remember that you are not alone and that you have nothing to be embarrassed about. While you may feel self-conscience about the appearance of your pregnancy scars, remember that there are solutions. As previously stated, the skin will begin naturally healing itself after the wound subsides. However, since scars develop when there is trauma to the skin, some aspect of the scar will always remain unless it is treated. Thankfully, there is a wide variety of scar treatments available on the market. Recently, studies have shown that silicone scar treatments have a very high success rate as well as being cost effective when compared with more expensive surgical scar removal treatments such as collagen injections and laser treatments.
source: http://www.scartreatmentassociation.com/pregnancy-scars.html