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Average Baby Weight By Month: Is Your Baby Growing Normally?

Average Baby Weight

The birth weight of a normal term newborn is usually between 5.5 and 8.8 pounds. Babies then generally gain an ounce a day for the first couple of months and about a pound a month after that. Check with your doctor if your baby’s growth pattern changes considerably.

While it’s amazing watching your tiny newborn grow, as a parent you might also be wondering if they are growing “normally.” Well, first of all, much like adults, babies do come in a range of shapes and sizes. And your baby will have their own unique rate of growth dependent on factors ranging from genetics to nutrition. But it is a good idea to keep an eye on the typical growth pattern to figure out if your little one is developing as they should. Here’s what you need to know.

Newborns Weigh Between 5.5 And 8.8 Pounds

At birth, a baby typically weighs between 5.5 and 8.8 pounds. A birth weight less than 5.5 pounds is considered to be low and one greater than 8.8 is considered to be high. There may not be any cause for concern if your newborn is heavier or lighter than average, but your doctor will pay extra attention just to be sure that there are no issues.

A low birth weight can be caused by many factors such as maternal health issues, problems with the placenta, genetic factors, premature birth, or substance abuse by the mother. And sometimes, a low birth weight baby may have a greater chance of developing infections or have delayed motor development or learning disabilities. Meanwhile, high birth weight can be caused when the parents are big or if the mother suffers from diabetes during pregnancy. A baby with high birth weight may have a greater chance of birth injuries or issues with blood sugar.1 2

Newborns Will Lose Some Weight In The First Week After Birth

It is normal for breastfed babies to show about 7–10% weight loss in the week after birth. Formula-fed babies will experience a 5% weight loss.3

During the first few days after birth, normal term babies usually lose around 5–8% of their birth weight. Newborns tend to carry excess fluid which they will shed in the initial days. This weight is typically regained by the end of the second week.

After this, babies generally gain an ounce a day for the first couple of months and about a pound a month after that. But they may not grow at a steady rate. Often babies experience a growth spurt at around 7 to 10 days and at 3 weeks and 6 weeks.4 5

Baby’s Weight Ranges From 7 Pounds In Month 1 To 26 Pounds in Month 12

The tables below can be used as a guideline to look at how your baby is growing. It is based on the World Health Organization (WHO) standards which describe the pattern of growth of babies in conditions conducive to optimal growth. The growth pattern of babies who were mostly breastfed for at least 4 months and continue to be breastfed at 12 months is reflected here.6

Percentiles, which are used here alongside weight, help you compare your baby with other babies of the same age. Here’s an idea of what exactly they mean:

  • If your baby is on the 85th percentile for weight at 2 months, 85% of 2-month-old babies weigh the same as or less than your baby and 15% weigh more.
  • If your baby is in the 50th percentile, they fall squarely in the middle.
  • If they are in the 15th percentile, 15% of babies of that age weigh the same as or less than your baby and 85% weigh more.

Most babies will double in weight by 3–4 months.7

Being in a lower percentile means that your child is smaller than other babies that age while being in a higher percentile means that they are bigger. Weight below the 3rd percentile and above the 97th percentile may, however, be monitored by your doctor as they are considered the cutoff values for appropriate weight.8 9

Premature Babies Are Smaller

Premature babies are typically smaller and weigh less than normal term babies. Their weight is mostly based on how early they were born. A premature baby needs to catch up on the “growing” time they missed in the womb and typically receive special medical care immediately after they are born.10

Being In A Low Percentile For Weight Isn’t Automatically Bad

There isn’t anything necessarily wrong if your baby is in a low percentile for weight. For instance, if you and your partner are smaller than average, it’s normal for your baby to consistently rank in a lower percentile as they grow up. However, if the percentile your baby is in changes considerably, that is they move from one percentile range to another drastically, it could mean that their growth rate is slowing down and you should talk to your doctor. However, do note that your doctor will usually take more than one measure of growth into account while figuring out why your baby’s growth rate has changed.11

Head Circumference And Length Are Also Used To Track Growth

All babies have a growth rate that’s unique to them. Your doctor will regularly measure aspects like weight, length, and head circumference to make sure that they are growing in accordance with their individual growth pattern. But here’s a reckoner that can give you an idea about how your baby is growing.

  • Length: Typically, normal tern babies increase around 30% in length during the first 5 months. By 12 months they are more than 50% longer than they were at birth.
  • Head circumference: This is also an important measurement that doctors track as it can indicate whether the baby’s brain is growing normally. When a baby is born the brain is one-fourth the size it will be as an adult and they should have a head circumference of around 14 inches. By the time your baby is a year old, their brain is three-fourth the size of their adult brain.12

If Your Baby Feeds, Pees, And Poops Normally, There’s Generally No Cause For Worry

If you’re worried about whether your baby’s gaining weight normally, don’t hesitate to speak to your doctor. How much a baby feeds and how often they need a diaper change can provide an indication of whether everything’s alright.

  • Feedings: Breastfed babies typically feed 8 times or more within 24 hours and spend about at least 10 minutes nursing each time. Meanwhile, formula-fed babies feed less often, generally once every 3–4 hours and may have about 3–4 ounces each time.
  • Diaper Changes: Initially a breastfed baby may have a couple of wet diapers in a day as the mother’s milk is still coming in but by 3–5 days all babies have around 6 wet diapers. This ranges between 6 and 8 wet diapers after that. Typically, breastfed newborns pass stool several times a day and formula-fed babies have fewer stools.13

References   [ + ]

1, 4, 10, 13. Your Newborn’s Growth. Nemours Foundation.
2. Birth Weight. National Institutes of Health.
3, 7. Monitoring Your Newborn’s Weight Gain. American Pregnancy Association.
5, 12. Physical Growth of Infants and Children. Merck Manual.
6. WHO Growth Standards Are Recommended for Use in the U.S. for Infants and Children 0 to 2 Years of Age. Centers for Disease Control and Prevention.
8. Growth Chart Training : Using the WHO Growth Charts. CDC.
9. Child growth standards. WHO.
11. Growth charts. Victoria State Government.

Disclaimer: The content is purely informative and educational in nature and should not be construed as medical advice. Please use the content only in consultation with an appropriate certified medical or healthcare professional.