My Toddler 1.5 yo keep waking up night every 2hrs sometime every 1hr

My Toddler 1.5 yo keep waking up at night every 2hrs sometime every 1hr. Is it because she eat less and drink less milk? She still drink from small bottle 120ml. Also when she sleep she drink abit sleep back 1hr later drink abit 30ml sleep back. How to make her sleep longer without wakeup many times :s. Anyone experience the same as my toddler?