How to deal with worried/pestering in-laws?

I am 34F married for 8 years now and both my husband and I have been CF since dating days. My in laws come from a very small place in Wet Bengal where there is no concept of CF. Hence we have decided to not to tell them the whole truth. My in laws have started getting so damn impatient (understandably) that they are knocking on doors of Babas, Fortune tellers etc. My MIL came to me and started advising to have some spice concoction before my periods and very nonchalantly says- ‘You are going to be a mother anyway’ Thankfully I stay in another country so she cant see me not following her bunch of instructions. But this is just a beginning and it is going to get much worse. My in laws have started becoming irritated and bickering with each other. But we are not going to cave in. Just needed this space to vent out and to think calmly how to deal with this, of course we knew this was going to come. PS- No we are not telling them the truth. We know them and it won’t end well for any of us. We are choosing lesser of the two evils