is it safe to do yogasans during pregnancy?

Yes, you can get a lot of benefits from practicing yoga.

http://s3cr3ty0stg2.wpengine.com/yoga-for-women/The-Benefits-of-Pregnancy-Yoga.html

http://s3cr3ty0stg2.wpengine.com/yoga-for-women/Kundalini-Yoga-Set-for-Pregnancy.html

Blessings