Being considerate

My sister-in-law has had 3 miscarriages (1 natural conception and 2 IVF) and I am newly pregnant (8 weeks, 1st US at 10 wks). I want to sensitive to her feelings but my husband and I are so excited to tell his parents. This will be their first grandchild. Does anyone have some good ideas on how to not make this look like we are gloating? We love her very much and she is a very kind and good person so we don’t think she will respond negatively. Any tips will be appreciated.