Babies may start out smaller or larger than other healthy newborns, but all of them should grow in an expected pattern in the first year of life. Regularly measuring their weight, length and head circumference and documenting them on growth charts is a regular part of well-baby care. This helps you and your baby's health-care provider monitor their overall health.
Growth and weight gain
All newborn babies lose weight in the first few days of life and regain it in about 10 to 14 days. Once they regain their birth weight, most healthy babies who are born full-term will continue to gain weight according to the following pattern:
| Age | Weight gain per day | Weight gain per month |
|---|---|---|
| One to three months | 30 g | 900 g |
| Three to six months | 20 g | 600 g |
| Six to 12 months | 10 g | 300 g |
A useful rule of thumb is that most healthy, full-term newborn babies double their birth weight by four months and triple it by their first birthday. Keep in mind, though, that all babies grow at their own pace. The rate of weight gain in the first few months of life is also affected by infant feeding, with differences seen between breastfed infants and formula-fed infants. Breastfed infants may gain weight faster in the first three months and slow down afterwards. Your baby may gain weight faster or slower than the rates mentioned above. A small or large baby may be perfectly healthy.
Babies have growth spurts and fluctuations in their rate of weight gain. Therefore, your baby might not stay at the same percentile for weight or height every time you bring them for a well-baby visit. If your baby was very large at birth, chances are that they will grow quite slowly for the first few months. By six to eight months, they will probably be close in weight to other babies their age. If your baby was small due to prematurity, they may catch up to a normal weight over the first year of life.
How do I know if my baby is growing well?
The best way to keep track of your baby's growth and weight gain is to bring them to their regularly scheduled well-baby visits. Their health-care provider will carefully measure and plot their weight, height and head circumference over time, and will compare the measurements to standardized growth charts.
Some babies do not gain weight as expected, and there are many reasons why that may happen. Read about poor weight gain for more information.
Head circumference
Along with your baby's weight and height, their head circumference will be measured at every well-baby visit. Your child's health-care provider will measure around your baby's head at its largest area: above the eyebrows and ears, and around the back of the head. The measurement will be recorded and compared with their previous measurements, and with the normal ranges for babies of the same age. Head growth generally relates directly to brain growth.