My second baby is just five months (Today actually!) and for the past few weeks we've been having split nights. She wakes up at around 1am or 2am, wide awake and will stay so for about two hours. She's not unhappy but is if I try and put her back down. Has anyone else had this, I've tried doing longer naps / shorter naps, changing bed times, morning etc. no joy yet. Any advice or experience appreciated?! Does it sound like part of the four month sleep regression, it's been going on for a while now! Zzzz