Advice please

My mother in law is extremely religious while I'm an atheist. My husband and I are TTC and it's been over a year and half. I've got PCOS and we're currently trying medical intervention to get pregnant. Just today my MIL says that I'm not getting pregnant because I don't pray. She insists that I do the morning prayers in the house. In spite of knowing my beliefs.

She's an extremely lovely person and we get along very well except for our beliefs. I've always respected her beliefs but I just feel like she's never respected mine. I've politely pointed this out several times but I still have to hear comments like this.

It's silly but it's just so frustrating when you're already stressing out over TTC. How do I deal with this?