They will ALWAYS be changing their sleeping patterns!. Just as you get used to a pattern, it can literally change overnight. When you think of all the factors affecting their sleep patterns, its hardly surprising. Growth spurts, developmental leaps, teething, illness. I found a book called 'the wonder weeks' incredibly reassuring and interesting. It tells you when the main developmental leaps happen and how it changes your babies brain. Changes in sleep patterns often go hand in hand with increased grizzlyness and clinginess and its all explained really well in wonder weeks.