I know the 45 minute waking thing is very common. My sister has a 4 week old and he wakes after 45 mins for every nap and some of the night. Could you try the wake to sleep method or is that not the right solution to this problem? She has been doing the s/p but he still wakes like clock work at 45 mins every time. She even tried doing s/p as soon as he starts stirring (going in before the 45 min mark to be ready for it right away), but he wakes all the way up, screams and cries and takes a long time to put back to sleep. When he does go back to sleep she has to hold him because when she tries putting him back down he starts up again. When she holds him he will stay asleep until the 3 hour feed time, have a good feed and not be too OT. Anything else she can try? How long should the s/p take to work?