Many women wonder if they can continue their regular activities during pregnancy. Yoga is a wonderful complement to pregnancy, and your regular practice can likely continue throughout all trimesters and after your baby's birth, keeping you fit and comfortable as your body changes to nourish your growing baby.
At any stage of pregnancy (and of life, for that matter) you should listen to your body for guidance. Each day might bring a different need or limitation. If you already practice yoga, you know how the poses normally feel, and you'll know when something feels odd. A good general rule is to not try any brand new asana during pregnancy--sticking to familiar poses will help you pick up on your body's signals when something isn't right.
If you experience dizzyness, nausea, pain, shortness of breath, irregular or rapid pulse, or other odd reactions during your practice, they are a signal to stop and rest. Call your doctor if these reactions continue after you stop, or if you have any swelling, vaginal bleeding or contractions.
A note on hot yoga: Most doctors advise to avoid elevating the body temperature above 100 degrees during pregnancy--especially during the first trimester. If you have been practicing Bikram-style hot yoga regularly for an extended period of time, you may be able to continue, but talk to your doctor to be sure, and definitely pay attention to your body, stopping practice and leaving the heated room if you experience any of the above reactions.
Some sources recommend avoiding inversions and deep twists during the early period of pregnancy to prevent injury to the developing placenta which could potentially lead to malformation or displacement of the placenta (and consequently miscarriage or necessary c-section if the placenta covers the cervix). No research currently supports or rejects this recommendation.
Talk to your doctor about the movements involved in your yoga practice. If your pregnancy is considered high risk, he will likely recommend that you avoid any strenuous activity. But for a typical pregnancy, the body of a regular yoga practitioner is well-equipped to perform inversions and twists without harming the baby or placenta.
In my own experience, although I could safely practice the styles of yoga that I did pre-pregnancy (ashtanga, power yoga and kundalini, all on the physically-demanding end of the yoga spectrum), the first trimester was exhausting. I have never felt as drained of energy as I did during weeks six through ten of my pregnancy.
When I could summon the energy for an asana-heavy class, my body did feel better. But getting adequate sleep during this period (up to 12 hours a day!) was so important. My yoga practice often consisted of a few sun salutations or spine-stretching exercises to stay comfortable, then a long savasana and welcome cat-nap.
At some point during the second trimester, you will truly begin to feel the presence of your baby. You will no longer be able to comfortably lie on your belly or twist as deeply. You may also feel a little wobbly in balancing poses as your ligaments loosen.
You can easily modify prone positions in your practice by coming to hands and knees, or even elbows and knees if you experience carpal tunnel during pregnancy. Instead of locust pose, you can come to hands and knees and extend one hand and the opposite leg to strengthen your back. Instead of bow pose, you may be able to come to hands and knees and reach your hand back to grasp your opposite foot, kicking the foot into your hand to open the front of your body as in bow.
For forward bends that tightly compress the belly, such as uttanasana or paschimottanasana, you can bring your feet hip-width apart to allow space for your belly between the thighs.
You will likely need to open your twists during this trimester. Instead of leaning forward for revolved side angle and squeezing your abdomen as you twist, you can start in a standing lunge, bring the opposite hand to your lunging knee, and reach the other hand behind you as you twist.
Balancing poses are safe to continue, but you may want to practice them near a wall or other solid object to correct your balance in case you begin to tip over.
Most women experience a surge of energy after the fatigue of the first trimester. Take advantage of this energy to remain physically active as your pregnancy progresses, so that you can remain comfortable throughout.
The hormone relaxin is released during pregnancy so that the pelvis can widen for childbirth, but it can loosen ligaments throughout your body. With this increased flexibility, you may be tempted to try the extra-bendy poses you've never been able to accomplish before. Practice caution as you stretch deeply, as overstretching can lead to imbalance, decreased support, and discomfort. If you feel discomfort after practice, it may help to stretch less deeply (think 90% instead of 100%) or to hold stretches for a shorter period of time.
You may want to avoid deep asymmetrical leg stretches, such as lizard or hanumanasana, entirely, as they can displace the pelvic bones, possibly injuring the sacro-iliac joint or leading to symptoms of Pubic Symphysis Disorder or sciatica.
To accommodate your growing belly, you can bring your legs wide for forward bends. You will likely twist more shallowly as your pregnancy progresses as well.
Inversions, such as handstands and headstands, are safe throughout pregnancy, but be careful. It is normal to lose abdominal tone and core strength as your abdominal muscles stretch. If you feel compression of your neck in headstand, you may need to avoid the pose until after your baby is born.
Most women are unable to lie on their backs for extended periods of time after (or beginning in) the second trimester as the weight of the growing baby compresses the inferior vena cava and slows blood flow back to the heart. If you experience discomfort while lying on your back, you can try elevating your right hip a few inches with a bolster, blanket or rolled towel. You can also lie on your side for savasana, supporting your top leg with a bolster to keep it as high as your top hip.
Save some extra time for pranayama and meditation before, during or after your yoga practice. Even if they are not a regular part of your practice, this quiet time can prepare you emotionally and mentally to welcome a baby into your life. A new baby comes with almost continuous needs, and although you will probably feel an upheaval in your life during the first weeks of caring for your baby, having a regular meditation practice in place can prevent these changes from becoming overwhelming.