/agree with LaRue on this.
Especially taking into account abdominal muscles- many people come into “toning”, “cutting”, or “spot reduction”.
Emphasize that the best way to lose abdominal fat is through total body fat percentage. Lowering it overall throughout the body will lead to a loss in the abdominal area.
Personally, depending on how long ago her pregnancy was I’d personally train muscular endurance and stabilization for back, shoulders, arms and legs.
Usually women go with the “off your feet, eat for two” mentality. Getting them back into shape usually means watching the portion size of meals and working on easy stress to the muscles.
It would also depend on what type of delivery she had. A c-section vs a vaginal birth effect the rectus abdominal differently.
I would first train with stabilization of the entire core. Much of this area changes during pregnancy and then afterward since the client is doing a lot more sitting for breastfeeding, changing diapers and holding a cranky, sleeping infant. Focusing on proper alignment while sitting and standing will also help the mom become more aware of their posture and how that affects their musculature.