Why does your skin sag after pregnancy?

Loss of elasticity: As the skin expands to accomodate the growing pregnancy, it will lose some of it's elasticity. Every woman is different and therefore will be affected by this differently. Somewhat obviously, the larger the baby, or with multiples, the skin will stretch more and this may ultimatley result in more sagging.

Many reasons: Skin sags for many reasons after pregnancy. One you gained weight and then lost it, the skin was stretched to allow the baby to grow and you put the weight on rather quickly.