In the first few days after birth, expect your newborn to lose weight. This weight loss is primarily due to the loss of excess fluid accumulated during pregnancy, and it is normal.

Most newborns begin to regain their birth weight within the first two weeks, and your pediatrician will track your baby’s overall growth during wellness exams. You don’t need to do anything extra to help your baby regain their birth weight other than follow their natural hunger cues.

As your baby starts to gain weight back, it will be less important whether or not they hit a specific number and more important that your baby shows a steady growth pattern.

Your pediatrician will share your baby’s weight as a percentile that compares them to their peers, according to one of two infant growth charts: the WHO chart and the CDC chart. The WHO infant growth chart is based on breastfed infants' growth, while the CDC infant growth chart includes data from both breastfed and formula-fed infants.

For example, if a baby is in the 10th percentile for weight, 90% of babies of the same age weigh more than them, and only 10% weigh less. Percentiles are just statistical markers and don't necessarily indicate health concerns.

Babies come in all shapes and sizes, and as long as your baby is following their growth curve and your doctor is not concerned, being smaller or larger is nothing to worry about.