OVERVIEW

What situations constitute overfeeding?

Overfeeding refers to providing infants with a volume of milk that exceeds their stomach capacity during the newborn or early infancy period, leading to discomfort or illness.

The newborn period spans from birth to one month of age.

When does overfeeding most commonly occur?

It frequently occurs in the early neonatal stage. A newborn's stomach capacity is very small, and the amount of milk they can tolerate within the first 7 days after birth is limited. Additionally, newborns have weak sucking reflexes and rely on primitive reflexes, making them unable to resist excessive feeding. Thus, overfeeding is more likely during this period.

Furthermore, during infancy, overfeeding may also occur if caregivers deliberately push for larger feedings.

What situations constitute underfeeding?

Underfeeding refers to situations where a baby does not receive sufficient milk.

When is underfeeding most likely to occur?

Underfeeding can occur at any time during infancy, which spans from birth to one year of age.

It is more common in the neonatal period, especially for low-birth-weight or preterm infants. Babies with low weight, younger gestational age, or fewer days since birth often have weaker sucking ability and may struggle to obtain enough milk. Their limited ability to express hunger may also lead caregivers to mistakenly assume they are not hungry.

SYMPTOMS

What discomfort can overfeeding cause?

Newborns may experience vomiting, spitting up, bloating, and persistent inconsolable crying (colic).

Long-term overfeeding in infants may lead to obesity during infancy.

What serious consequences can overfeeding cause?

• Overfeeding mainly causes discomfort in babies, leading to repeated crying and restlessness, which may cause anxiety or depression in parents.
• Long-term overfeeding can also result in infant obesity, which may persist into school age and adulthood, increasing the likelihood of metabolic syndrome later in life.

What are the possible signs of underfeeding?

Babies who do not receive enough feeding may exhibit frequent crying, reduced urination (normal newborn urination frequency is once in the first 24 hours, increasing by 2–3 times daily afterward, reaching 6–8 times per day after 5 days), dark yellow urine, reduced bowel movements, and continued passing of black or dark green meconium more than 3 days after birth.

Weight loss in the first 7 days after birth is normal, but if weight loss exceeds 10% of birth weight within 7 days or if birth weight is not regained within 10 days, it indicates underfeeding. The American Academy of Pediatrics recommends seeking medical evaluation for underfeeding if a newborn's weight loss exceeds 7% of birth weight.

What serious consequences can underfeeding cause?

• Hypoglycemia and brain damage: If a baby does not receive enough feeding for an extended period or is already underweight (less than 2.5 kg), hypoglycemia may occur. Severe hypoglycemia may cause the baby to become unusually quiet, making it harder to detect. Severe or prolonged hypoglycemia can lead to permanent brain damage.

• Severe jaundice: Insufficient feeding in newborns increases the risk of hyperbilirubinemia, making severe jaundice more likely.

• Malnutrition and developmental delays: Long-term inadequate intake can lead to protein-energy malnutrition, affecting growth and development.

CAUSES

Which feeding method is more likely to cause overfeeding?

Overfeeding is more likely to occur with formula feeding. Since breast milk can adjust its secretion according to the baby's needs, breastfeeding does not lead to overfeeding.

For formula-fed babies, parents need to judge the amount of milk, and sometimes incorrect judgments can result in the baby consuming too much milk.

Is overfeeding caused by improper formula feeding?

Infant sucking can be divided into two modes:

• One is "nutritive sucking," which requires the baby to concentrate and coordinate the palate, tongue, and jaw to suck and swallow, aiming to satisfy hunger.
• The other is "non-nutritive sucking," where the baby does not need to exert much effort to extract breast milk but uses gentle sucking motions for comfort. Non-nutritive sucking helps reduce stress, promote weight gain, and aid digestive tract maturation.

During breastfeeding, non-nutritive sucking does not lead to excessive milk intake. However, formula-fed babies use bottles, which require minimal effort to suck, so even non-nutritive sucking can result in milk intake, increasing the risk of overfeeding.

Parents often notice that after breastfeeding, if they continue bottle-feeding formula, the baby may still exhibit sucking motions, mistakenly assuming the baby is still hungry. This leads to increasing the milk amount, causing the baby to consume extra milk and eventually experience discomfort.

Which feeding method is more likely to cause underfeeding?

Exclusively breastfed babies are more prone to underfeeding, especially within the first 7 days after birth.

If the mother has undergone a cesarean section or is in a poor health condition, milk production may be insufficient, leading to inadequate breastfeeding for the baby.

If the baby has difficulty sucking, struggles to latch properly, or cannot suck effectively, they may also fail to receive enough milk.

DIAGNOSIS

How to Tell if Your Baby is Full

The following signs indicate your baby is full:

• The baby releases the nipple voluntarily after feeding, with relaxed facial muscles and hands.

• If the baby falls asleep while nursing, they won't wake up when the nipple is removed or will easily fall back asleep.

• After feeding, the baby can sleep peacefully or play for at least an hour.

• Without additional water intake, the baby's urine output is normal (one wet diaper in the first 24 hours after birth, increasing by 2-3 wet diapers daily, reaching 6-8 wet diapers per day after 5 days).

• The baby's weight gain is on track.

How to Tell if Your Baby is Hungry

Early hunger cues include sucking on hands or blankets, sticking out the tongue to lick blankets, smacking lips, and turning the head from side to side. At this stage, the baby is still calm and not crying intensely. It's best to feed them at this point to establish a positive interaction cycle.

If early hunger signals are missed, the baby may become fussy, wave limbs, and eventually progress to loud crying.

TREATMENT

Which department should I consult for overfeeding or improper feeding?

Neonatology, Child Health Department, or Pediatrics.

What should I do if I accidentally overfeed my baby?

If it's just a one-time occurrence and the amount isn't excessive, it's generally not a major issue. A baby's stomach has some elasticity and can temporarily accommodate more food. Simply reduce the next feeding amount or delay the next feeding.

How to increase breast milk supply?

• Increase skin-to-skin contact between mother and baby, which can stimulate prolactin secretion and boost milk production.

• Increase the frequency and duration of breastfeeding to ensure sufficient suckling, as suckling promotes prolactin secretion.

• Empty the breasts completely during each feeding, as this also stimulates milk production.

• If the mother cannot breastfeed directly due to inverted nipples or other reasons, an electric breast pump can help with milk expression and breast emptying.

• Stay well-hydrated, get adequate sleep, and maintain a positive mood.

DIET & LIFESTYLE

How Much Milk Does a Baby Need?

Breastfed babies do not require strict measurement of milk intake. Simply feed on demand and recognize signs of fullness. If formula supplementation is needed, refer to the following guidelines for milk volume calculation.

Generally, for formula-fed babies, newborns on the first day need 5–10 mL per feeding, increasing by 10 mL daily thereafter. Babies aged 7–30 days typically consume 90–120 mL per feeding. After that, the volume increases by about 30 mL per month until reaching 210–240 mL per feeding by six months of age.

The formula amounts mentioned above are general guidelines. Since each baby’s growth varies, adjustments may be necessary based on individual needs.

PREVENTION

How to Prevent Overfeeding?

Determining whether the baby is full is the most crucial step. For specific methods, refer to the question "How to tell if the baby is full?"

If the baby remains unsatisfied after consuming an adequate amount of milk, try offering a pacifier. If the baby calms down after using the pacifier, it indicates non-nutritive sucking for comfort rather than actual hunger.

This is especially important for formula-fed babies, as bottle feeding provides shorter sucking time, which may leave the baby without sufficient sucking satisfaction. A pacifier can meet the baby's sucking needs while preventing excessive milk intake and reducing air swallowing.

How to Prevent Underfeeding?

• Start feeding early: Initiate breastfeeding within 15 minutes to 2 hours after birth to help the baby receive colostrum and stimulate milk production.

• Recognize hunger cues: For specific methods, refer to the question "How to tell if the baby is hungry?"

• Monitor feeding frequency: Newborns may need to be fed every 1–2 hours. Feed the baby on demand as soon as hunger signs appear. If a newborn sleeps soundly for more than 4 hours, wake them for feeding.

• Master proper breastfeeding techniques: Effective sucking requires coordination between the mother and baby. If the baby struggles to latch properly and cannot suck effectively, they may not get enough milk. Hospitals have lactation consultants—seek their help if breastfeeding is challenging.

• Supplement with formula if necessary: If a professional assessment confirms insufficient breast milk, supplementing with formula while continuing breastfeeding can prevent underfeeding. Additionally, methods to increase milk supply can be found in the question "How to increase breast milk production?"