It's not normal, no, especially if a baby loses more than one pound. A baby doesn't have many pounds to begin with, so losing weight could be dangerous.
I suggest the baby and the mother be taken to the doctor that oversees the two of them. There could be a problem with the breast milk, but there could also be a problem with the baby.
The previous poster is wrong. It is expected that babies lose weight after birth. It is only a cause for concern if they lose more than 10% of their birth weight. The normally gain it back in the next couple of weeks.
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