One of the side effects of childbirth can be the weakening of your pelvic floor. During your pregnancy the hormone progesterone is used to help soften and relax your muscles and ligaments so that your baby can make their way out of your pelvis and vagina. The side effect of this is that it can stretch those muscles a great deal. This means that many moms can often experience a weakness of the bladder when they laugh, sneeze or even when they lift something.