Ostashevskaya-Gohstand prefers a light free-weights program for clients with no discomfort in their joints, as she says they get "extra benefits like core strengthening and balance training."
Don't compromise your balance doing standing exercises, such as walking lunges, with hand weights. With the increase of the hormone relaxin, both hip and ankle joints become loose and will not give you the support you need. Additionally, your center of gravity has shifted and you won't be as stable.
Weight machines such as the leg extension, seated leg curl, lat pull, incline bench press, triceps push down, and seated shoulder press are all good choices for prenatal exercises. Always make sure that your back is supported and your weight is centered.
Pregnancy tends to put weight on in some areas more than others. Although it is impossible to take fat off one area alone, combining aerobic exercise and specific outer/inner thigh and hip exercises can decrease the chances of excess fat being stored on the hips and buttocks. Abdominal exercises can still be done, but not traditional crunches. Hand and knee cat stretches and using a fitness ball can help keep your abs strong.
Floor exercises such as side leg lifts, hip rotation, and inner-thigh lifts can keep your legs toned and fit. You can also do many exercises seated in a chair using rubber tubing. Make sure you are comfortable in whichever position you choose—your body can tell you best how it feels. Any shortness of breath, dizziness, sharp pains in the pelvic region, nausea, or swelling of your hands, feet, or ankles is not normal, and is a sign you should stop exercising and consult with your doctor.
Exercising throughout pregnancy should not add extra stress to your life. Instead, if done safely and effectively, it should help you release stress, stay healthy, and have a more enjoyable pregnancy.