How can I be sensitive to my sister's struggle TTC?

TL;DR my sister miscarried a year and a half ago and is struggling to get pregnant. How can I best be sensitive to her pain after becoming pregnant the first try?

My sister and her husband had a miscarriage about a year and a half ago. They've been struggling to conceive since. We got pregnant the first month we tried and are 7-8 weeks along.

They recently moved to California for his job, which neither of them was overly happy about. I waited until my mom was down there to tell her. She was happy for me, but my mom said she cried after she got off the phone. I feel so bad for her and I don't want to talk too much about the baby. She did ask the other day, but I don't bring it up otherwise.

Any advice on how I can be kind and sensitive toward her?