Brother And Sister In Law Never Happy For Us..?

Agree. But in family dynamics such as what you have described (BIL tripping over himself to inform your MIL about your good news), it is better to take the high road, share news at one time to all, and assume that they are as happy for you as you are for them. Forgive the temporary lack of enthusiasm.. maybe they were confident they'd have a second child before you did... whatever.. As long as one is not living in the same house, such matters can be small stuff not to be sweated. Learn from it, fine tune your interactions and move on.

Strongly disagree. Parents do not always try to do what's best for their children. Unlearning that belief takes so many avoidable bitter experiences for the adult child. If a mother or MIL promises the pregnant woman and father-to-be that she will keep her mouth shut till 12 weeks or whenever.. she should follow that. The reason is that no matter how logical we are, when it comes to pregnancy, we want to err on the side of superstitions and not share the news too early. As to the constant digs... as the mother of two almost adult children, I have learnt how to deal with digs of any kind. After being temporarily shocked on couple of occasions at how could close friends make such insensitive comments about temporary real/perceived setbacks or delays in my children's lives, I became the devil incarnate, issuing fitting retorts and if needed ruthlessly editing out of my life people and events that don't help me.

Do I not blab about my children's stuff to my close friends? Yes, I do. Sometimes my friends know more than my husband does about some issue my child and I are fighting over/about. But, there is a line at which such sharing stops. As the children grow into adults, such lines become even more distinct. I plainly tell people who ask nosy questions about stuff related to my children, "That is her/his story to share. Ask her/him."