My sister-in-law and close friend just had a miscarriage at 4 weeks pregnant a couple of weeks ago. I just found out that I am pregnant for the first time and would really like to share the news with her, but am waiting for the right time to share. She is not one to seek sympathy or mope, but she still has a heart and I know she's been hurting. Her mood seems much better, but I don't want this to "re-injure" her and remind her of her loss. On the other hand, I'm worried that if I wait several weeks she'll wonder why I didn't tell her sooner. 

 (Note: Her first pregnancy ended in a miscarriage, then she had two healthy boys, and most recently she had her second miscarriage.)

How and when do you think I should tell her? Any experience with miscarriage and how your healing went about?