Many women receive IV fluids during labor and/or childbirth. The baby also receives this fluid while still inside the woman, causing the baby to be born with an extreme excess of bodily fluid. The baby's body will get rid of this excess fluid, or diuresis, over the next several days after birth, causing a noticeable decrease in the baby's weight. This is not a true weight loss or cause for concern, bur rather a sign the baby's body is responding to correct this fluid overload.