Physical development between 1 and 12 months of age
Babies grow rapidly during the first year of life. Weight, length, and head circumference measurements are plotted on growth charts to monitor your baby's growth over time. Most babies:
- Grow about 3 in. (7.6 cm) to 4.5 in. (11.4 cm) in length by 4 months of age. Although growth may slow slightly between 4 and 7 months of age, by 12 months of age most babies have grown a total of about 10 in. (25.4 cm) in length since birth and measure somewhere between 28 in. (71.1 cm) to 32 in. (81.3 cm).
- Gain an average of about 4.5 lb (2 kg) to 6 lb (2.7 kg) by 4 months of age. Birth weight usually doubles by 6 months of age and triples somewhere between 9 and 12 months of age. This is an average gain of 0.5 oz (14.2 g) to 1 oz (28.4 g) per day for the first 6 months.
- Head circumference grows about 0.25 in. (0.6 cm) to 0.5 in. (1.3 cm) per month.
The soft spots, or fontanelles, on top of a baby's skull begin to close at 6 months but won't completely grow together until sometime between the 9th and 18th month.
When your baby is about 6 months old, teething may also begin. Teeth may not yet break through the gums at this age, but your may baby drool, chew on objects or hands, and act fussy from the pressure of new teeth coming in.
It is important to keep in mind that each baby is different, and growth patterns can change between routine well child checkups. If you have concerns, talk to your health professional about the many factors that can influence your baby's growth. Normal and expected physical growth requires adequate nutrients and a nurturing environment.
| Author: | Amy Fackler, MA | Last Updated: April 14, 2006 |
| Medical Review: | Michael J. Sexton, MD - Pediatrics Louis Pellegrino, MD - Developmental Pediatrics | |
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