How to tell an infertile family member

I've been having mixed feelings about this. They have been trying for about two years and she has a low egg count. We already have one child and are now expecting our second. I don't know how to tell her without the awkwardness. My sister in law had 3 kids in 3 years and when our family member that is having issues found out about her expecting the last one it got really awkward. I love her and don't want to hurt her but I also don't feel like I should hide my pregnancy to accommodate her! What do I do?!?