Gripe water is more for gas in stomach, not really for poop I feel. It's a bit tricky since breastmilk babies can go up to 10 days without pooping but formula fed babies should be pooping everyday or once every 2 days at least. So I guess every 3-4 days is an average. For my baby she poops every 4 days now, she's 6 months old. When she was 7 weeks she pooped only once a week; although I knew it was okay but still worrying for me. We are on full breastmilk. If it worries you, you can include prune juice in your diet and take some probiotics yourself. Also you could let her take the probiotics which is most direct. Should see results in a day or two! :) A popular brand among mummies:
If your baby appears to be fine and does not show any signs of illness, you do not have to bother too much about the frequency. My baby is entirely breastfed and she has gone without pooping for 4 days. Sometimes, she poops more than once a day. It's irregular. IF you feel your infant is suffering from constipation, a teaspoon of prune juice can be added to milk. I wouldn't bother too much about it. http://sg.theasianparent.com/your_babys_poo/
thanks