Megan Atwood 
Attack of the Nightmare Nappies [PDF ebook] 

In the midst of a boring summer, schoolgirl Angie Del Mar discovers something amazing about the eccentric woman who’s just moved into town. She is actually a mad scientist who plans to take over the world by enlarging and controlling insects! With the help of her friends Cooper, Genevieve and Harvey, Angie nabs the mixture and flees. But before they reach safety, the friends encounter a nursery where the mixture is accidentally released. Soon the town is overcome by gigantic toddlers! Can the friends save the town, defeat the scientist and restore the bawling, blubbering behemoths to their cute and cuddly size?