Hi anon - generally if you are new to yoga I would recommend being super cautious around pregnancy and also asking a health care professional. There is a lot of (often contradictory) information around yoga and falling pregnant and the only agreement is that whilst it is good to do some yoga some caution should be exercised around some postures and styles particularly the more strenuous, dynamic ones like ashtanga. Obviously it also depends on you - how fit you are, age, weight, etc and one should always defer to listening to one’s own body - thats part of the lesson in uniting body and mind through yoga.
Regards
Chris