Is it normal for my 5 month to regurgitate every single time we feed. Can be watery kind and undigested milk. One feed at least 5 times she regurgitate. Sometimes can be straight after finish milk since she was born. I have reduced her milk from 160 ml all the way to 80 ml then slowly increase back to 160 ml till she's 5 month but it happen .. What should I do?

Babies tend to burp out or spit some milk out in the first 6 months. Once they know how to sit upright on their own it gets better. It sounds like your baby has some reflux issues. My gal used to have this issue too and we tried to change her milk power to those suitable for reflux AR type but nope it made her worse. AR milk powder is thicker which makes the milk stay inside their stomach. I think it made my gal have more bloatedness. Do you burp your baby a few times during feed? Try doing that. Otherwise you have to make sure you hold her upright or at least 45 degrees for half an hour after milk feed and that includes the night feeding. Yes I did that for six months! Avoid letting baby move too much after feeding. If baby needs to sleep after feeding try to let her lay on her left side as this helps digestion and elevate her mattress. If her reflux is so serious that her weight gain is not good PD will put her on reflux Med but they usually won't do that unless the weight gain is bad. Time will solve this reflux issue so hang in there!!

was it all a sudden she started regurgitating milk or since newborn days? I would advise you to go to a doctor for proper advise to rule out any issues with baby since she is so young

Please go to the doctors and not delay. It's hard for anyone to say what could be happening. Better be safe then sorry.

I think better to bring to pd. See if it could be lactose intolerant or something