At last count, I’ve worked with over 20 mothers at various fitness levels who wanted to do what they could to make their pregnancies, deliveries, and recoveries as safe and successful as possible. Through my collective experience, I’ve learned that movement is, indeed, medicine—and that a safe exercise program can help both an expectant mother and her baby in many ways, as long as it follows well-established and science-backed guidelines. Here are some of the most important principles that have led to success in my work over the years.