Hi OP
You sound so lovely and really considerate - please don’t feel guilt for your pregnancy, your family member won’t want that.
I was in a similar situation and got fab advice on here. My best friend had a terrible loss (well they’re all terrible but I mean she was hospitalised, the physical side lasted longer than most etc) and ultimately I text her.
The advice I received was from women who were in her shoes and so I really listened to it.
They explained pregnancy loss brings feelings like nothing else and that whilst she may ultimately be happy for me (you in this case!) that it may be masked or mingled with huge sadness, anger etc. and she may choose to step back a little while she processes.
They suggested texting and saying there was no pressure to respond but that you were there if they wanted to chat.
My friend was so incredible that I was actually a bit overwhelmed, and she’s remained completely selfless throughout my pregnancy by taking care of me, asking questions and not showing any feeling she’s may be having of it being hard on her. That doesn’t mean she isn’t feeling it so I try to be considerate without cutting her out. Others have shared stories that haven’t gone so well with the person who has lost stepping back slightly but just know this is self preservation and then managing their own emotion and self care. It doesn’t mean they don’t love you or want the best for you it’s just a coping strategy.
This is a snippet of a wider message I sent her in case it helps:
I wanted to let you know that I’m pregnant. I had my 12 week scan today and am due in March.
I’m really conscious that you may be feeling a whole raft of complicated emotions and that it’s ok for you to not text back etc. but please know I just want you to be OK. I love you and if you want to talk, I’m here xxx
Hope your conversation goes well, however you choose to do it (or have done it!!)