Why Your Breastfed Baby Is Not Gaining Weight

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Most breastfed babies will gain weight in a consistent and expected pattern as long as they latch on well and feed often. But if you're breastfeeding and your newborn is gaining weight slowly or inconsistently, they may not be getting enough breast milk.

Adequate nutrition is, of course, essential to your baby growing and thriving. Here's what to look for and what to do if you think your baby is not gaining weight as expected.

Typical Weight Gain for Breastfed Babies

All babies grow at their own pace, but baby weight gain does tend to follow a fairly consistent pattern. Breastfed newborns can lose up to 10% of their birth weight during the first five days of life. Then, by the time babies are 10 days to two weeks old, they should regain the weight they lost. After that, for the next three months or so, breastfed babies gain about an ounce a day. By 4 months old, babies will usually double their birth weight.

Of course, every newborn is different, and some children normally grow more slowly than others. As long as your baby is breastfeeding well and their health exams are on target, a slower weight gain may not be an issue.

But weight gain is the best sign that a child is getting enough breast milk. When a baby is gaining weight slower than expected, it could mean that they are not getting enough. If your newborn is not back to their birth weight in two weeks, or not gaining weight consistently after that, it may indicate that there's a breastfeeding issue.

At-Home Scales

Weighing your baby at home is not a substitute for taking your baby to the pediatrician. It can, however, be a great way to work with your child's doctor to be sure your baby is gaining a healthy amount of weight.

Reasons for Slow Weight Gain

There are a number of reasons why your baby may not be getting enough breast milk to gain weight consistently. Your doctor and/or a certified lactation consultant can help you determine the issue and correct it.

Poor Latch

A good latch allows your child to remove breast milk from your breast without getting tired and frustrated. If your baby is not latching on correctly or is latching on to just your nipple, they won't be able to remove breast milk very well.

Infrequent Breastfeeding

Breastfeed your newborn at least every two to four hours through the day and night for the first six to eight weeks. If they want to breastfeed more often, put them back to the breast.

Short Nursing Sessions

Newborns should breastfeed for about 8 to 10 minutes on each side. As your child gets older, they won't need to breastfeed as long to get the breast milk they need. During the first few weeks, however, try to keep your baby awake and actively sucking for as long as you can.

Pain or Discomfort

If your baby is not comfortable because of a birth injury or an infection such as thrush in her mouth, they may not breastfeed well, and therefore may be gaining weight slowly.

Low or Delayed Breast Milk Supply

Some mothers may have a delay in the onset of breast milk production, which means production is either slow or late. Other mothers experience chronic low milk supply, which can have several causes that may work individually or in combination to reduce the amount of milk a child receives when breastfeeding. The good news is that a low milk supply can often be improved fairly easily.

Although it's not as common, some medical issues can cause a true low breast milk supply. You may still be able to increase a true low milk supply, but it's more difficult. It needs to be treated and followed by a doctor.

Risk Factors for Poor Weight Gain

While most newborns and infants will breastfeed well and gain weight, some babies are more likely to have difficulty breastfeeding. When a child is at risk for breastfeeding difficulties, the chances of growing and gaining weight at a slower pace are higher.

  • Being born premature or near term: Smaller babies or those born before 37 weeks may not have the strength or energy to breastfeed for a long enough time to get all the breast milk they need. They are also more likely to be sleepy and experience medical issues which can make breastfeeding even more difficult.
  • Oral challenges: It can be difficult for any baby to latch on if his mother has hard, engorged breasts and/or large nipples. However, infants with small mouths or a physical issue such as a tongue-tie or a cleft lip and palate can have latching troubles regardless.
  • Jaundice: Newborns with jaundice may have a yellow tone to their skin. This condition can make babies very sleepy and not interested in breastfeeding.
  • Reflux: Infants with reflux spit up or vomit after feedings. Not only do they lose some of the milk from feeding, but the acid from the reflux can irritate their throat and esophagus, making it painful to breastfeed.
  • Illness: Infants with an illness or an infection may not breastfeed well. They may not gain weight or they may even lose weight, especially if they have diarrhea or are vomiting.
  • Neurological issues: Conditions such as Down syndrome can impede a baby's ability to latch and nurse properly.

How to Help Your Baby Gain Weight

If you are concerned about your child's weight gain, or lack thereof, it is essential to see your baby's healthcare provider as soon as possible. They will examine, measure, and weigh your baby and give you a sense of what is expected at their age. They also will suggest strategies that may help your baby gain weight such as perfecting their latch, breastfeeding often, avoiding pacifiers, keeping your baby awake, addressing supply issues, and considering supplementing. Here are some additional tips on helping your baby gain weight.

Check Your Child’s Latch

Make sure your baby is latching on to your breasts correctly. Ask your doctor, a lactation consultant, or a local breastfeeding support group for help. They can observe your baby and determine what changes need to be—if any.

Breastfeed Often

Nurse your baby every two to three hours and whenever they show signs of hunger. Don't put your baby on an every three- to four-hour feeding schedule like a formula-fed baby. Since breast milk is more easily digested, breastfed babies need to eat more often.

Avoid Pacifiers

If your baby sucks on a pacifier instead of nursing, they won't be getting as much breast milk. A pacifier can also tire your baby out, so they may not nurse as well when they do get to the breast. Once your baby is breastfeeding and gaining weight well, offer the pacifier if you want.

Keep Your Baby Awake

Try to keep your baby actively breastfeeding for about 20 minutes at each feeding. Try to keep sleepy newborns awake by tickling their feet, changing your breastfeeding position, changing their diapers, burping them, or using the switch nursing technique.

Address Supply Issues

If the problem is your breast milk supply, take steps to increase your milk production. Besides breastfeeding more often, you can pump between feedings, add some milk-boosting foods to your meals, or try breastfeeding herbs or teas.

Consider Supplementing

If your baby's doctor thinks it's necessary, you may have to supplement your baby with additional feedings of either pumped breast milk or infant formula. You can also try to pump and separate your foremilk from your hindmilk. Hindmilk is higher in fat and calories, which can help your baby gain more weight.

Should You Stop Breastfeeding?

As long as it's safe for your baby, you can continue to breastfeed exclusively while working closely with your healthcare provider to monitor your baby's weight gain. Depending on your situation, you may decide to partially breastfeed or breastfeed for comfort. If you do wean from the breast, you can choose to exclusively pump, switch over to infant formula, or give your child a combination of both.

Infant formula is a safe alternative. And for many moms, it's the only way to ensure that they have a healthy child who is growing and gaining weight well. Achieving that goal is what's most important. If you need to change your breastfeeding plan, feel good that you tried your best and you're doing what you need to do for yourself and your child.

4 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Academy of Pediatrics. First month: Physical appearance and growth.

  2. Neumours Children's Health. Your Baby's Growth: 4 months

  3. Stanford Children's Hospital. Slow or poor infant weight gain.

  4. Centers for Disease Control and Prevention. How much and how often to breastfeed.

Additional Reading
  • Cadwell K, Turner-Maffei C, O'Connor B, Cadwell Blair A, Arnold LDW, Blair, EM. Maternal and Infant Assessment for Breastfeeding and Human Lactation A Guide for the Practitioner Second Edition. Jones and Bartlett Publishers, 2006.

  • Dewey KG, Nommsen-Rivers LA, Heinig MJ, Cohen RJ. Risk factors for suboptimal infant breastfeeding behavior, delayed onset of lactation, and excess neonatal weight loss. Pediatrics. 2003;112(3 Pt 1):607-19. doi:10.1542/peds.112.3.607

  • Lawrence RA, Lawrence RM. Breastfeeding A Guide For The Medical Profession Eighth Edition. Elsevier Health Sciences, 2015.

  • Riordan J, Wambach K. Breastfeeding and Human Lactation Fourth Edition. Jones and Bartlett Learning, 2014.

By Donna Murray, RN, BSN
Donna Murray, RN, BSN has a Bachelor of Science in Nursing from Rutgers University and is a current member of Sigma Theta Tau, the Honor Society of Nursing.