will the newborn baby's weight will decrease after 2 weaks from their born day

A. Yes, at first. Babies are born with some extra fluid, so it's normal for them to drop a few ounces when they lose that fluid in the first few days of life. A healthy newborn is expected to lose 7% to 10% of the birth weight, but should regain that weight within the first 2 weeks or so after birth.