Question: how much weight should newborn gain by one month?
Answer: Remember that most babies lose some weight during the first few days of life, but usually regain this weight over the next few days so that within a week to 10 days they're back to their original birth weight. 1 to 4 months: Babies usually gain 1 1/2 to 2 pounds and grow 1 to 1 1/2 inches each month.