My DH and I had been married about three years, and we had to live with my in-laws briefly in between moves. His mother began CONSTANTLY dropping hints about having grandchildren. Well, lo and behold, I got pregnant while we were living there, in their basement (we slept on the fold-out sofa bed.) We were trying to hold off telling them immediately, but just a day or so later, MIL was harassing us again about how she is never going to have grandchildren. My DH turned to me and "I have to tell her before I explode!" So he did. I have never seen that little woman jump and dance and scream and cry so much. It was great. But it was funny when she finally calmed down and realized exactly WHERE the baby must have been conceived.
I don't think I've seen her sit on that sofa since. 
It's amazing how people can draw a line in their minds between
give me grandkids!!! and
have intercourse with your partner!! 
Your MIl basically ordered you to have unprotected sex but for goodness' sake not in her basement. *shakes head* You weren't teenagers or newlyweds anymore either.
That's why I think it is the height of rudeness to pester people about their reproductive choices above and beyond saying: "Do you want kids some day?"
I'm glad your MIL was so happy though!

Waltraud
PS: Speaking of Royal Audience: When Louis and Marie Antoinette tried for Royal Grandkids, at least a dozen servants were present. And when Empress Elizabeth and Emperor Franz had their wedding night, both MIL's (who were sisters at the same time) kept watch in front of the door all night. So no pressure there!