Restorative yoga can provide great benefits during pregnancy; yoga poses for lower back pain are particularly helpful. We have some suggestions to work into your daily exercise routine.
Yoga Precautions During Pregnancy

It's common for regular yoga practitioners to follow a modified pregnancy routine right up to the baby's birth. But, if you're new to yoga or don't practice often, please note the following precautions:

If you attend a yoga class, tell the instructor you're expecting. She or he will guide you to modifications best suited for your condition.
Most instructors advise mothers not practice Hot Yoga, Power Yoga or Bikram Yoga during pregnancy. These styles have a far greater intensity, and are often performed in hot rooms. These conditions raise your internal temperature and may put the baby at risk.
Poses to avoid while pregnant include deep bends, abdominal twists, and inverted postures. You should also refrain from performing Corpse Pose/Relaxation Pose after the first trimester.
Gentle Pregnancy Poses for Lower Back Pain

Hormonal changes, pregnancy weight gain, and the baby's growth and repositioning can really put a strain on your spine. Doing some simple pregnancy yoga poses for lower back pain can provide relief. Here are a few to try.

Cat/Cow Pose: The combination of Cat Pose and Cow Pose work well to release pressure on the spine. Get on all fours and open your legs a little wider than hip-distance apart. Arch up into Cat by tucking the chin down to the chest as you curve the back. On your next inhale, ease into Cow by lifting the chin and the tailbone up to the ceiling. Alternate positions by moving with your breath.
Child's Pose: This is a great posture for lower back pain or even just to unwind for a few minutes. From all fours, sink down onto your heels. Use a pillow or folded blanket behind your buttocks to make this more comfortable. Open your knees to accommodate your belly, and fold forward, resting your arms and head in front of you. You can use a pillow under your head. Sink into the floor and breathe deeply, and if you are content, hold Child's Pose for a few minutes.
Cobbler's Pose: This posture opens the hips and relieves pressure on the lower spine. Draw your legs together at the bottoms of the feet. Place folded blankets or blocks under each knee. If you can, gently hold each ankle. Straighten your back and inhale, letting your shoulders fall from the ears. Exhale deeply. Continue to sit quietly for a few minutes following your natural breath rhythm.
Transitioning between Cat Pose and Cow Pose helps release tension.
Downward Facing Dog Pose: By elongating the spine in Down Dog, you release tension throughout the back. Start in Mountain Pose, arms at your sides and legs together. On an exhale, fold forward at the waist and walk your hands forward, dropping the chest and head between the upper arms. Lift your tailbone high as you bring your heels closer to the floor. Hold for 20-30 seconds. To come out of the posture, walk your legs forward to meet your arms. Place your hands on your shins and support your rise by moving your hands up the legs until you return to Mountain Pose.