5.5 month baby suddenly waking?

[KimchiLaLa]

DD has been a decent sleeper and from about 4 months was sleeping through, with some random wake ups in between which I put down to development leaps. However for the past three nights she has woken at 1.30ish (and 4am one night). I thought she may be teething but when she wakes she just talks to herself, doesn't cry. Yesterday I fed her and put her back down, then she settled herself. I'm not sure she needed feeding so may not feed her if she wakes again tonight. The one change I've made is switching from ready made to powder formula - could it be affecting her tummy? She's not crying when she wakes but maybe it has done something?

Sleep regression - you will find a million articles about it on the internet.
Not hunger, teething, overtired, undertired, needing weaning, changing... just pure good old sleep regression.
Every other thread on here seems to be about it... welcome to the crappy club
Seems to vary wildly with how long it lasts though and mixed opinions on what to do to help, if anything

It's probably hunger related.

That said, I would not reintroduce night feeds after so long without them. The simplest way to deal with this is give more daytime feeds.

I assume you so ready give bottles that contain more formula than baby will drink, so there us always an excess left over? In which case the way to get more milk into baby is to make bottles closer together so that you add one or two extra feeds in per day.

For example if you usually feed 3 hourly, try 2 hourly. Or feeds ever 2h30m. This may mean 7 bottles throughout the daytime.

Also make sure you feed-wind-feed again at every feed. Reoffer the bottle after a break for winding.

It's not unusual for night feeds to return around weaning age (I note you are not far off). This is because there are more easily accessible calories in milk that anything else you can give baby. So ensure daytime milk feeds are maintained when weaning. Don't give food instead of milk. Give food as well as milk. Otherwise baby will end up hungrier due to a calorie deficit.