The American College of Sports Medicine suggest the following guidelines:
“Generally, exercise in the postpartum period may begin four to six weeks after delivery and with permission from a physician. Women who deliver via cesarean section may require more than six weeks after delivery to begin exercise. Deconditioning typically occurs during the initial postpartum period, so women should gradually increase exercise until prepregnancy physical fitness levels are achieved.”
A woman who has given birth for the most part falls within the population of “apparently healthy.”
Exercises that involve strengthening the musculature of the axial skeleton (a.k.a. the core) and then working on the musculature of the appendicular skeleton would be a good approach.
If you apply the principles of designing an exercise prescription as they apply to the components of total fitness in a progressive manner, the healthy postpartum client will get back into shape.