Why Has My Baby’s Weight Gain Slowed?

Your baby was growing by leaps and bounds – he’s a huge, plump breastfed baby. But now that he’s a little older, it seems like he’s not gaining weight as fast. And you’re worried that he’s not getting enough milk or that your milk supply is disappearing. So, what’s going on?

From birth to six months, breastfed babies average about 4-7 ounces (113-142 grams) of weight gain each week. But from six months to one year, that weight gain normally slows to about 2-4 ounces (50-80 grams) per week. Other resources suggest babies gain about one pound (1/2 kilogram) per month from six months to one year. Your baby should regain his birthweight by 10 to 14 days of age, double his birthweight by 4 months and triple his birthweight by one year.

If you are tracking baby’s weight gain on growth charts, be sure the ones you are using are the most currently WHO growth charts for your country, which are based on the average growth of breastfed babies. Tracking baby’s weight gain on older charts that were developed using formula fed babies can make it seem like baby isn’t gaining enough.

Some things that could impact your baby’s weight gain include:

  • Your baby’s genetic body type and metabolism: For example, long, lean babies tend to be above average for length but below average for weight on growth charts.
  • Your baby’s temperament: Calm, laid back babies may burn fewer calories so gain weight faster; while their more active counterparts use up more energy and seem to gain less weigh overall.
  • Your baby’s developmental stage: As your baby starts crawling and walking, more calories are being expended on movement and are no longer just being stored as fat.
  • Your baby’s breastfeeding pattern: Babies who are fed on cue (including throughout the night) tend to grow faster – and this growth is appropriate. Babies whose feedings are scheduled and who are trained to sleep through the night tend to have slower growth.

Sometimes a baby’s weight gain does slow due to a dip in mom’s milk supply. If you think this is the case for you, nurse or pump more often to boost supply, and consider these possible causes:

  • Have your periods recently returned? Hormonal changes may cause a dip in supply for some moms.
  • Have you started using hormonal birth control? Again, the change in hormones can lead to low milk supply.
  • Are you pregnant? The hormonal changes necessary to sustain pregnancy do cause a milk supply to diminish.
  • Are you taking any medications? Some medications can impact milk supply, especially antihistamines and pseudoephedrine.
  • Are you recovering from illness? Some moms see a decrease in supply if they have been sick, especially if they have been at all dehydrated.
  • Is your baby getting a bottle more than occasionally? Any decrease in breast stimulation will lead to a decrease in supply.
  • Has your baby just started sleeping through the night? Again, those missed nighttime feedings can cause milk supply problems.

If you suspect baby’s slowed weight gain is due to milk supply challenges, the help of a lactation consultant can be essential.

For most babies, though, slow weight gain in the second half of the first year of life is completely normal, especially if they stay on a similar growth percentile as plotted on a WHO growth chart.

Written by Michelle, childbirth instructor, lactation consultant, and mother to 4 busy kids

This information is not intended to replace the advice of a trained medical doctor. Health & Parenting Ltd disclaims any liability for the decisions you make based on this information, which is provided to you on a general information basis only and not as a substitute for personalized medical advice.  All contents copyright © Health & Parenting Ltd 2016. All rights reserved.