Is newborn need to drink plain water?

When my older daughter born, this question never occurred to me, so somehow I never gave her any plain water. However, later on, I sometimes saw a mother gave her baby plain water. Then it hits me. Does baby, specially newborn, need plain water beside the one already mixed in the formula milk?

Then the other day, my mother in law told me to give my new born daughter plain water, since she “seems thirsty”.

I tried to googled that question, and this is my findings:

Baby less than 6 months are not suppose to drink plain water. They should have enough water from the one that mixed in the formula milk or from your breast milk. The reason is because water has no nutrient and giving water will fills their tummy so they don’t want any milk.

Of course, if your baby has constipation, or some other problem and your pediatrician advise you to give extra plain water, you must follow.