For those who frown on American words, the words mom and diaper are used. Those are easy to translate to mum and nappy.
I love this book. It goes from mom being pregnant to when the parents have to go to the hospital and when they come home with a baby. It talks about the siblings feelings and how the baby will behave so it isn't a surprise. As another reviewer stated that it does talk a little bit about adoption. Also, this book also uses both gender pronouns so you can tailor it to your child and baby.
I think the most important issue the book talks about is love, mom and dad still love their first child just as much after the baby comes. I promised my daughter at least 30 minutes everyday. I will spend time with her throughout the day, but the 30 mins will be our special time as newborns are unpredictable.
My daughter is still anguish about the new baby, but this book certainly helps and it deals with emotions that are often hard to deal with for anyone.