D.K.
I am three months along with my sixth child. Everyone thought we were done because our fourth child died 31 weeks after conception and our fifth died 14 weeks after conception. To be honest we weren't expecting the sixth. Burying our two was very hard and I am now forty years old. In my opinion, God slipped one in because we were to chicken and he knew it would make us happy. We haven't told my in-laws because my mother-in-law is not all that nice about more babies and I want to avoid all stress. My husband thought he would tell them, "since I got him a motorcycle that he thought it was only fair I should get a baby." He is silly and tends to make absolutely no since. We are praying like mad that this baby lives! My five year old is very honest. She says, "We want this one not to get dead because it isn't fun putting babies in the ground."
As for your SIL my heart goes out to her. It is very hard when people get pregnant around you after your babies have died. We had a family get together after our babies had died. They had both past away within a year. One of my Aunts made a big deal about all the babies that had been born in the year as she past out gifts to the mothers who had living babies. I know she meant well, but it broke my heart!!!! Be so careful with her! One thing that really helped me when my little ones died was a friend that made and effort to call me on their due dates and give me flowers on the anniversary of their deaths. I don't know how your SIL looks at things, but I feel that every one of my children are gifts and I love them all. I can never replace the two that died they are now my little saints in heaven, praying for me always. I will say a little prayer all goes well.