From the Guidelines
Most babies regain their birth weight by 7-10 days of life, as stated in the 2018 Clinical Nutrition study 1. When to expect a baby to regain their birth weight is a common concern for new parents. It's normal for newborns to lose up to 7-10% of their weight in the first few days of life due to fluid loss and limited initial feeding.
- Breastfed babies may take slightly longer to regain their weight compared to formula-fed babies, with a median time to recover birth weight around 8.3 days for breast-fed infants and 6.5 days for formula-fed infants, as observed in population-based cohorts of healthy neonates 1.
- Your baby should be gaining about 0.5-1 ounce (15-30 grams) per day after the initial weight loss period.
- Regular feeding is essential for weight gain - newborns typically need to eat 8-12 times per day.
- If your baby hasn't regained their birth weight by the two-week check-up, your pediatrician may recommend more frequent feedings or supplementation.
- Adequate wet and soiled diapers (about 6-8 wet diapers and at least 3-4 bowel movements daily) are good indicators that your baby is getting enough nutrition, as suggested by the 2004 Pediatrics study 1. However, the most recent and highest quality study, from 2021, published in Blood Reviews 1, also supports the idea that babies usually regain their birth weight by 10-14 days after birth, which is consistent with the 2018 Clinical Nutrition study 1. It is essential to monitor your baby's weight gain and feeding patterns, and contact your healthcare provider if you're concerned about your baby's weight gain or feeding patterns.
From the Research
Regaining Birth Weight
- Generally, newborns can lose up to 10% of their birth weight during the first week of life and should regain it by two weeks of age 2.
- However, the time it takes for a baby to regain their birth weight can vary depending on several factors, such as whether they are breastfed or formula-fed, and their overall health 3.
- For full-term, breastfed newborns, the mean weight loss is usually 6% to 7% of birth weight by 2 days after birth, and 7% to 8% by Day 3, with most newborns regaining their birth weight by 10 to 14 days 4.
- Preterm babies typically take longer to regain their birth weight, with a median time of 18 days in one study 5.
Factors Influencing Regaining Birth Weight
- Birth weight, mode of delivery, and daily average weight gain are significant predictors of regaining birth weight among preterm neonates 5.
- The use of formula supplementation in the first 24 hours of life can impact breastfeeding rates at discharge, with early and higher volumes of formula supplementation negatively impacting breastfeeding rates 6.
- Exclusive breastfeeding rates decrease when newborns lose greater amounts of weight 4.
Variations in Regaining Birth Weight
- The time it takes for a baby to regain their birth weight can vary significantly, with some studies suggesting that term babies typically regain their birth weight in 7-10 days, while preterm babies may take 10-15 days or longer 5.
- The amount of weight loss and the time it takes to regain birth weight can also vary depending on individual factors, such as the baby's overall health and feeding habits 3.