The fact that your daughter is passing adequate amounts of urine rules out the possibility of not getting enough breast milk; if you are having constipation yourself, this could explain why she is constipated. Another possibility is that she is not tolerating the milk formula well in terms of digestion (in case you are also supplementing her with formula milk). The short term solution would be to administer a Glycerine nourisson suppository: split it in halves vertically, coat it with Vaseline petroleum jelly, and gently introduce it into your baby's behind. For more sustained results and prevention of recurrent constipation in your child, make sure that you yourself do not get constipated, and if you are indeed giving her supplemental milk formula, try shifting to the Comfort subgroup of the same brand in case the constipation recurrs or persists.