Advice for telling sister

So I just found out I’m pregnant (we were trying) so yay!

But my sister has been struggling with infertility and has done a few rounds of

IVF

...

She knew we were trying and I know she’ll be happy for us but I know it will sting too. I just don’t know the best way or when to tell her.

I just need advice.

She also lives half the US away from me so in person isn’t a choice.