Telling my boss I’m pregnant

I’m 19 weeks pregnant with my second I’m kinda showing, I haven’t told my lead yet, my boss overall knows but I don’t know how to tell my lead. She can be a bit harsh at times she’s a lot older than me and has not kids or is married to understand....

Any tips on how to tell her ??? Or how to approach.

Also I been seeing a high risk doctor and have so much going on this time.