How to tell a friend

I have a friend who suffers from a condition that makes it very difficult from her to get pregnant. She has a daughter, so it’s possible for her, but she’s been trying for the better half of last year and has failed to conceive. I recently found out I’m pregnant, after 5 months of trying, and I’m so afraid to tell her for 2 reasons. For one, I feel so bad for her that she’s been trying to get pregnant and hasn’t been able to. I hate to think I’m rubbing it in her face that I’m pregnant. And for 2, she gets very upset over things like this. She told me about another friend of hers that’s pregnant and said she’s very sour about it, then started making fun of the name her friend picked out for their baby. My friend is a very good friend that has my back through anything, but when she gets mad she gets seriously passive aggressive and just plain mean. So how do I go about telling her in the softest way possible?