job interview and yoga while pregnant

okay so i’m 16 weeks pregnant and in desperate search of a new job. i applied to and had a phone interview for a sales supervisor position at a yoga studio. it went well but she said she’d like for me to try a class and then have an in person interview. i’m not really sure how to approach this as i didn’t really plan on mentioning i was pregnant. i googled it and you can do yoga but are supposed to avoid certain poses. what should i say to the hiring manager ?