14month old sleeping issues

So it doesn't happen all the time, but quite often baby wakes up in the night and seems irratable. She will fuss around and eventually go back to sleep, some night's

it's not so bad but other nights she wakes up so frequently like every hour or so. She's doesn't need changing and I don't want to give her milk because she definitely eats enough during the day. We find that it's best just to leave her alone and let her go back to sleep. If we disturb her too much, likelihood is she won't go back to sleep and we're all shattered in the morning. Does anyone have any idea why this could be happening? She has been constipatied recently... And she naps roughly 2 hours during the day. Its been going on for a few weeks now. She seems perfectly fine during the day, no sign of being unwell and generally very happy and normal... I know babies can have odd sleep patterns but just concerned if anything could be causing. Any advice will be much appreciated xx