How much weight should my baby gain each day?

For preterm babies, weight gain is one of the best signs that they’re growing well. The exact amount depends on the baby’s gestational age, size, and health, but here are general guidelines most NICUs use:

• In the NICU:

  • Babies are expected to gain about 15–20 grams per kilogram of body weight per day.

  • For example, a 1 kg (2.2 lb) baby would ideally gain 15–20 grams per day, while a 2 kg (4.4 lb) baby would ideally gain 30–40 grams per day.

• General ranges:

  • Very preterm babies (<32 weeks): may gain a little less at first, but the goal is to “catch up” to what they would have grown inside the womb.

  • Late preterm/near term babies (34–37 weeks): often gain more steadily, closer to 20–30 grams per day.

• Big picture: The goal is for preterm babies to grow at a rate similar to a baby still in the womb at the same age. That means steady weight gain, along with head growth and length growth. Look at the graph below to see how your medical providers track your baby's growth each week.