I know the feeling you are having, and ironicly it is from the other point of view. I watched my sister have so many fertility problems during her 20's and early thirty's, while I just kept having babies. She had her first dd at age 18, got married at 20 and tried for 14mo, finally got her ds. For her two babies, I had 2. Then all the problems began for her. She went on to have three of four losses over the course of 6yrs, one being a tubal which resulted in the removal of the tube. Then many cysts which ended her up back on b/c pills for about 6 months to get her regular again. I had another baby while she was going through all of this and finally she had her third about 6yrs of trying for her. I became pregnant when she got pregnant with her dd at same exact time. I could not even tell her I was pg, until after we found out her baby had a heart beat. She was so mad at me for getting pg at the same time, because she was afraid of another loss and having to witness another pregnancy for me. We had our daughters 10 days apart in the end, and through the whole pregnancy she was a bit t
imid with me, becasue she couldn't shake the fear.
Its so hard when its our sisters that we are going through these things with. I remember praying to god and telling him, "if her baby does not have a heart beat, give her mine please". I never told her these thoughts, as I felt it was just to personal. Maybe your sister feels the same way