How to tell sister in law?

Melissabride09

I have a question and I was hoping others could help.  My sil and I started trying for our first around the same time as each other a few years ago.  This weekend, I found out I'm pregnant with our second and my sil and brother are still waiting for their first.  I've seen several other posts where the general consensus is to tell them in a text or email so they're free to react and say whatever they want.

 I guess my question is, is there anything specific I should or shouldn't say?  She and I have a great relationship, I just don't want to say anything that I might think would be well-meaning, but might hurt her.  I feel sick for them and I don't want to say or do anything that might add to their pain.