DD2 has just come through week 55. I think she hits them all early, having been born 2+ weeks beyond 40. I don't know because I lose track of how many weeks old she is, but I do notice the leaps once they're over. I'm really lamenting week 55, she's jumped right out of babyhood!

DD1 made it far clearer when she was in a WW. I think there's a good buffer either side anyway. But most of ours have been pretty accurately spaced.

FYI: cancel all engagements for week 18/19.