I have tried about eight different pregnancy workouts,and have found this to be the only one that feels like a real WORKOUT. So many of them are nice and relaxing and teach you about breathing, kegels, etc., but the exercises are incredibly easy. This one got my heart-rate up a bit, and left me sore the next day (in a good way). It's great for someone who already has an established exercise routine. Erin O'Brien is a wee bit annoying, but what I like is that she's doing the workout in her own living room, using the couch, coffee table, and wall as props, and she works you hard. She combines a few aspects of pilates and yoga with her cardio and strength exercises and leaves you feeling like you did something good for your body.