As Brenda K. Plakans writes, 'Being pregnant is almost a yoga practice in itself. You have to practice vairagya (nonattachment) for nine months with so many things: fitted clothes, favorite foods, intense physical activity. You also become aware of your responsibility to the person growing inside of you, which requires a sense of selflessness. Instead of focusing primarily on the physical, many yoginis find their practice becomes more internal as the pregnancy progresses.'
If you are lucky enough to experience a fairly healthy pregnancy, the second trimester is usually an enjoyable time for the pregnant woman. Energy levels usually improve, nausea dissipates, and you can enjoy your growing bump without feeling uncomfortable or overly large.
Yoga asanas can definitely be of benefit during this special time. By using supported postures, and modifying your asana to suit your growing belly, you are able to alleviate some discomforts you may be experiencing. Some common complaints during this time include dizziness, sleep issues, mild swelling in the hands and feet, headaches, lower back pain and perhaps even varicose veins or cramping in the legs due to extra weight.
Chest and hip openers are very nice for this time..
Tones and strengthens the muscles of the legs, ankles, feet, arms and shoulders.
Improves balance and posture.
Increases strength of the abdominal, back and torso.
Helps develop pelvic stability
If you are practicing at home or alone, make sure you know what muscles you are working in certain asanas and how to protect yourself in postures.
Make sure you protect your pelvic floor in certain postures such as wide-legged standing poses (Virabhadrasana II) as it is already straining.
After week 20, pregnant women should avoid lying on their backs for extended periods of time because the baby and uterus then put pressure on a major vein which circulates blood from the lower back area to the heart.
Try and have a bolster, block, strap and any other supporting props you may have to give you support if you need.
Not all of these poses will be suitable for everyone, if a posture is uncomfortable for you (especially during pregnancy) come out of it immediately, yoga should not be uncomfortable during this time, it should relieving for you.