I know that traditionally folks wait until the second trimester, but Sanya seemed really excited about being pregnant and wanted to share her joy with everyone else. She wanted her whole family to be part of it. Unfortunately, as you noted, miscarriage is also part of reproduction, and I think that normalization can lead to destigmatizing it and help parents feel less alone in their grief. Hopefully everyone who knew she was pregnant offered her a community of support when the pregnancy ended.

Also, we know that production often shows things out of the order they were filmed. I wouldn't be surprised if some of the announcement scenes were filmed later than the doctor's visit.