When to tell the in laws

My mother help pay for the IVF treatments & she's been helping with the shots. My in-laws haven't really been involved that I know of (my husband doesn't want me to be stressed out so idk how much he has told them). I was in the hospital for 3 day for hyperstimulation & stuck at home for 2 weeks. I didn't receive 1 phone call or visit from them. My husband want to tell them (even though I'm only 4 weeks along). He's agreed to wait until the first ultrasound (3/10) but he feels bad that my mom (not my brother or sister) knows. I obviously want to wait the 12 weeks to tell them. What should I do?