Need advice!

My mother in law is really pressuring us to announce to my in laws. Aside from the fact we have told her multiple times we want to wait for our ultrasound next month, she is struggling to not let it slip.

That's not so much my issue - my issue is that we don't want to announce to them until we are able to talk to my SIL. She has been struggling with infertility for years and her sister recently announced her pregnancy... I'm dreading telling her because it hurts. I know it hurts from our experience but she laid in her closet crying for 30 minutes after her sister told her.. she is genuinely very angry over their circumstance.

Just feels cringey that we did a toast today over Easter brunch with friends but our own family doesn't know. So I guess my real question is, what are the best ways to do it? I'm not expecting her to be excited for us... I don't want to do it over text... and I want her to have space to feel whatever she needs so in person doesnt seem ok either.