Why Is Your Baby not Growing Well?
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Why Is Your Baby not Growing Well?

You expect your baby to grow. From time to time, your pediatrician weighs and measures your baby to make sure their growth is normal. Most babies gain in weight and length steadily, to your doctor’s satisfaction (and yours!)

Nevertheless, this doesn’t always happen. Some babies don’t grow well. Their weight increases very slowly or even decreases from one weighing to the next. Undoubtedly, this is a worrisome situation.

What is your baby’s expected growth? Your baby should gain 30 grams (one ounce) a day in the first three months, or 900 grams (2 lb) a month. This number is just the average, of course. Your baby may gain somewhat more or less than this number and still be perfectly healthy.

However, if your baby’s growth is significantly less than this, your pediatrician will look for the cause.

Poor growth can be the first sign of a serious disorder

Why Do Babies Not Grow?

  • Inadequate feeding
  • Improper formula
  • Sucking difficulty
  • Swallowing difficulty
  • Excessive vomiting
  • Indigestion or poor absorption
  • Metabolic and developmental disorders

Inadequate Feeding

This is the most frequent cause of a baby not gaining weight adequately, hard as it is to believe. Deliberately underfeeding a baby is rare, but several reasons result in inadequate feeding.
Poor lactation. You want to breastfeed your baby, but may not be able to produce enough milk. This can be because of sickness, exhaustion, or other reasons.
Not enough formula. Some babies just need more than the chart on the tin says. Remember, your baby must leave a little in the bottle. If they’re emptying the bottle, they’ve not had enough.
Expressed breastmilk not enough. If you’re back to work and pumping milk before leaving, it may not be enough for the time you’re away.

Improper Formula

Ready-to-drink formula eliminates errors, but is the most expensive. Formula concentrate and powdered formula are cheaper, but you must prepare them with care. Follow the instructions exactly. Some sources of errors are:

  • Not measuring the water or formula concentrate/powder.
  • Diluting the formula because you think your baby has gas or indigestion.
  • Making your own formula at home, which may not have enough nutrients.
Commercially available formula is best, and must be prepared carefully

Sucking difficulty

Breastfeeding needs effort. Babies need to latch on efficiently, creating an airtight seal to generate enough negative pressure to draw milk. Some babies are unable to do it:

  • Premature and other low birth weight babies
  • Babies with cleft lip or palate
  • Anomalies of the jaw or tongue

Swallowing difficulty

Sucking and swallowing in a coordinated manner are needed to draw milk into the mouth and pass it down into the stomach. Some disorders make it difficult for a baby to swallow efficiently:

  • Cerebral palsy
  • Neuromuscular disorders
  • Oesophageal anomalies
  • Chromosomal disorders like Down’s syndrome and others like Pierre-Robin syndrome

Babies with swallowing difficulties often choke while feeding or aspirate milk into the windpipe and lungs. If this is happening, your pediatrician will try to identify the cause of the swallowing difficulty.

Excessive Vomiting

Spitting up a small quantity of milk after feeding is quite normal. Your baby brings up a small amount of breastmilk or formula, which dribbles out of the side of the mouth. Your baby is not troubled by this.

Vomiting is forceful, and large amounts of breastmilk or formula are brought up. Your baby may cry or show other signs of distress. If this happens several times a day, weight gain is affected.

Such repeated vomiting can have underlying disorders:

  • Gastroesophageal reflux
  • Hypertrophic pyloric stenosis

Indigestion or poor absorption

Some babies are unable to absorb the nutrients in breastmilk or formula. Consequently, they don’t grow well. Some reasons:

  • Birth anomalies like malrotation and short gut
  • Diseases like cystic fibrosis
  • Specific nutrient digestion disorders like lactose intolerance

Metabolic and Developmental Disorders

Children with developmental disorders often don’t grow well. Several metabolic disorders are also associated with poor growth and weight gain.

False alarms about a baby’s growth are frequent. A spurt in length often makes a baby appear thinner till the weight gain catches up.

Babies lose up to 10% of their birth weight in the first three or four days. By the age of ten days, they recover from this loss and then start gaining weight. Weighing a baby in the first week often finds a weight less than they were born with.

On the other hand, genuine failure to thrive and weight loss does occur. If you feel your baby is growing poorly, talk to your pediatrician. Several disorders first show up as poor growth, and your alertness can help diagnose them early.


Engel-Hoek, et al. Feeding and Swallowing Disorders in Pediatric Neuromuscular Diseases: An Overview.

Goh LH, et al. Failure to thrive in babies and toddlers.

Homan GJ. Failure to Thrive: A Practical Guide.

Krugman SD and Dubowitz H. Failure to Thrive.