I have bought my DD 'There's a House Inside my Mummy' and she just loves it but I think it is a little obscure to understand the concepts so I also have another book called 'The New Baby'. It is an Usborne First Experiences book. It follows the story of the Bunn family and what happens when they have a new baby. How they prepare for it, what happens when the baby comes and Grandma & Grandad come to look after the kids while mum goes to hospital (it doesn't go into detail so probably not ideal if you are planning on having your toddler at the birth or if you aren't going to the hospital . . . ) and what happens when the baby comes home. There is a picture of the mum breastfeeding and although it doesn't say much in the text, I have talked to DD about what will happen when I bf our new baby.

It is a simple book, with a simple story but easy enough to talk about with a toddler.

I think reading a few different books has helped DD to understand better what is going on. My SIL had a baby last week which has also helped because DD recognised that her tummy wasn't big anymore and there was a baby. I think it is a whole heap of little things that help the concept to sink in.