Expected Baby Weight at 3-6 Months

Newborns gain weight rapidly at first, but as the months pass, the gain slows down. The goal isn’t to get as big as possible as fast as possible, but rather to maintain a steady rate of growth over the long term. Normal weight varies widely for babies. Rather than comparing one child’s size to other children, compare to the child’s previous weight. Here’s a look at what to expect regarding the weight for your baby.

Newborn Weight

A healthy, full-term newborn generally weighs between six and nine pounds, although anywhere from 5.5 to 10 is perfectly normal. Low birth weight refers to babies who weigh less than 5.5 pounds at birth and encompasses premature babies. Most newborns also lose about 10% of their body weight before they come home from the hospital, but that should return within two weeks. If your newborn continues to lose weight, you may need to supplement breastfeeding with formula or look for other reasons for a failure to thrive. Talk to your pediatrician if you are concerned.

Normal Growth Patterns

On average, newborns return to birth weight by week two. For the first month, most babies gain about an ounce a day, or one-and-a-half to two pounds per month until the third or fourth month. By three to six months, this slows down to about half an ounce each day or one to two pounds a month. Most babies double in weight by six months and triple by twelve months. So, if your baby weighs an even 7 pounds at birth, expect him to lose about .7 pounds (11.2 ounces) in the first day or two. By two weeks, he should weigh seven pounds again, 14 pounds by 6 months, and 21 pounds by 12 months. Furthermore, breastfed babies tend to be leaner than formula-fed infants between 4 and 12 months by about a pound, according to a University of California at Davis study. This is normal and should not be cause for concern.

Factors that Impact Weight Gain

Just like adults, all kinds of factors can impact how much weight babies gain -- temperament, body shape, and genetics, in particular. Babies who are fussy or more active burn more calories and gain weight more slowly than calm and content babies. Some babies gain inches faster than pounds, while others do the opposite and gain weight before a big growth spurt. As long as your little one is healthy, happy, and thriving, there’s usually little cause for concern.

Understanding Growth Charts

Growth charts were developed by combining the measurements of tons of kids to find average ranges of height, weight, and growth. If your child is in the 50th percentile for weight, 50% of the babies are lighter and 50% of the babies are heavier. “Normal” ranges from the 10th to 90th percentile -- or as long as height is fairly consistent with weight.

For example, concerns arise when a child is in the 5th weight and 30th height percentiles, which means he or she isn’t gaining rapidly enough. Concern can also arise from the opposite end -- 75th weight and 15th height, which means your child is growing too rapidly. Additionally, a baby in the 20th percentile at one check-up and the 60th at the next (or vice versa) is cause for concern as well.

Last Updated: April 06, 2018