From the Guidelines
Newborns should gain 17-20 grams per kilogram per day, which translates to approximately 119-140 grams or 4.2-4.9 ounces per week, to prevent growth failure and ensure proper development, as recommended by the most recent and highest quality study 1. This rate of weight gain is crucial for very low birth weight infants, and it is essential to monitor their weight closely to ensure they are meeting this target.
- The initial postnatal weight loss is a normal phenomenon, but it is vital to regain this weight by 10-14 days of age.
- Adequate feeding, whether through breastfeeding or formula feeding, is necessary to support this growth rate.
- Regular weight checks during well-baby visits are essential to monitor this aspect of infant development and identify any potential issues early on.
- The recommended weight gain is based on a strong recommendation and strong consensus, with a level of evidence (LOE) of 2+, and a recommendation grade (RG) of 0, indicating a high level of confidence in the recommendation 1.
- It is also important to note that the energy needs of newborns may vary, and the use of breast milk fortifier, preterm formulas, and preterm follow-up formulas may be necessary to meet these needs, as suggested by other studies 1.
From the Research
Expected Weekly Weight Gain for Newborns
The expected weekly weight gain for newborns can vary depending on several factors, including their birth weight, gestational age, and feeding method.
- A study published in 2020 found that the time it takes for a newborn to regain their birth weight is a strong predictor of their growth velocity 2.
- Another study published in 2019 found that healthy, full-term, breastfed newborns typically lose 6-7% of their birth weight by 2 days after birth, and 7-8% by 3 days after birth, with the nadir of lost birth weight occurring on days 2,3, or 4 after birth 3.
- By 10-14 days, most newborns regain their birth weight, with a weekly weight gain of around 150-200 grams per week for exclusively breastfed infants 3.
- A study published in 2014 noted that all infants lose weight after birth, but the amount and timing of this weight loss can vary, and supplemental feedings may be considered if the weight loss is excessive 4.
Factors Affecting Weight Gain
Several factors can affect a newborn's weight gain, including:
- Birth weight: Newborns with lower birth weights tend to have higher growth velocities 2.
- Gestational age: Premature infants may have different growth patterns than full-term infants 5, 6.
- Feeding method: Exclusively breastfed infants may have different weight gain patterns than formula-fed infants 4, 3.
- Nutritional intake: Adequate nutrition is essential for healthy growth and development, and nutritional supplements may be beneficial for some newborns 5, 6.