A school friend on FB is posting that her baby was up for fives hours last night, grizzling. He is six weeks old. So more than likely it is the six week growth spurt, She has decided to try and put him into a four hour routine of 6oz she is EFF. Comparing this to my daughter's six week spurt where she BF constantly it seems so wrong. Not the FF in itself of course - that is her choice - but trying to force a young, growth spurting baby into a routine. I wish there was better education for formula feeders around growth spurts and demand feeding - rather then people simply following the schedules on the back of the boxes :-(