The exercises shown are sometimes called "functional movement enhancers" because they increase the strength of the muscles that you use for everyday functions such as walking, carrying, lifting, sitting, and standing. The workout can be used alongside walking, swimming, or other cardiovascular exercises and can be done around 2-3 times a week.
The biceps is an important muscle for carrying and lifting. You can use 3-5 lb (1-2 kg) weights for this sequence if you're a regular exerciser. Stand with feet hip-width apart, knees slightly bent, back straight, and arms at your sides. Breathe in, then exhale as you bend one elbow, raising your hand to shoulder level. Alternate arms until you've done 20 curls each side (40 in total). If you find this easy, try doing a total of 60 curls.
These (and the forward lunges,) strengthen the abdominal and thigh muscles. Start with hands on hips, legs hip-width apart. Step one leg out to the side, bending the knee. Keep the other leg straight. Step back to the starting position, keeping the tummy pulled in and torso straight. Do 10 lunges on each leg.
Start with hands on hips, feet hip-width apart. Step one leg forward; bend the opposite knee toward the floor, allowing the heel to lift off the floor. Return to the starting position. Do 10 lunges on each leg.
This exercise works your bottom, hamstrings, and inner thighs, and builds strength in your lower body to support your growing belly. Lie on your back with your feet flat on the floor and knees slightly apart. Raise your hips (this relieves pressure on your back and is safe in the second and third trimesters). Keep your hands on the floor next to you, arms straight. Slowly bring your knees together while clenching your bottom; open and close your knees 10 times. Slowly lower your hips and roll onto your left side to end.