Medical Conditions

Slow Weight Regain in Newborns

Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist

Content reviewed against published AAP, WHO guidelines

Editorial policy

Last reviewed:

If your baby has been diagnosed with or you suspect slow weight regain in newborns, here is what the evidence says.

The short answer

Most babies regain their birth weight by 10-14 days of age. If your baby has not regained birth weight by 2 weeks, it may indicate feeding difficulties, insufficient milk supply, or other medical issues. Close follow-up with your pediatrician and a lactation consultant can help identify and address the problem.

Key takeaways

  • Most babies regain their birth weight by 10-14 days of age. If your baby has not regained birth weight by 2 weeks, it may indicate feeding difficulties, insufficient milk supply, or other medical issues. Close follow-up with your pediatrician and a lactation consultant can help identify and address the problem.
  • Usually normal when: Gradual weight regain that reaches birth weight by 10-14 days
  • Call your doctor if: Significant weight loss continuing after the first week, or baby not regaining any weight by 2 weeks
  • Varies by age — see the age-by-age breakdown below
“Fever itself is not an illness — rather, it is a sign or symptom that the body is fighting an infection. Fever stimulates certain defenses, such as the white blood cells, which attack and destroy invading bacteria.”
— Fever and Your Child, American Academy of Pediatrics (AAP)

Parents everywhere have the same worry. You are doing the right thing by looking into it.

What Parents Should Know

According to AAP, WHO guidelines, most babies regain their birth weight by 10-14 days of age. If your baby has not regained birth weight by 2 weeks, it may indicate feeding difficulties, insufficient milk supply, or other medical issues. Close follow-up with your pediatrician and a lactation consultant can help identify and address the problem. At 0-1 month, if your baby has not regained birth weight by 2 weeks, your pediatrician will want to evaluate feeding. Common causes include poor latch, tongue tie, insufficient milk supply, sleepy feeding, or underlying medical conditions. Your pediatrician may recommend more frequent weight checks, feeding evaluation, and possibly supplementation with expressed breast milk or formula while the underlying cause is addressed. Working with a lactation consultant is highly recommended. Adequate wet diapers (at least 6 per day after day 4) and stool output are monitored alongside weight. It is generally considered normal when gradual weight regain that reaches birth weight by 10-14 days. However, you should contact your pediatrician promptly if significant weight loss continuing after the first week, or baby not regaining any weight by 2 weeks.

Sources: [1], [2]

Normal vs. Concerning

Usually Normal
Worth Discussing
Gradual weight regain that reaches birth weight by 10-14 days
Significant weight loss continuing after the first week, or baby not regaining any weight by 2 weeks
Some babies regain slightly slower but are feeding well and producing adequate diapers
Baby shows signs of dehydration: fewer than 6 wet diapers per day, sunken fontanelle, dry mouth, excessive sleepiness, or lethargy
Steady weight gain after birth weight is regained
Baby has not regained birth weight by 2 weeks

By Age

What to expect by age

0-1 month

If your baby has not regained birth weight by 2 weeks, your pediatrician will want to evaluate feeding. Common causes include poor latch, tongue tie, insufficient milk supply, sleepy feeding, or underlying medical conditions. Your pediatrician may recommend more frequent weight checks, feeding evaluation, and possibly supplementation with expressed breast milk or formula while the underlying cause is addressed. Working with a lactation consultant is highly recommended. Adequate wet diapers (at least 6 per day after day 4) and stool output are monitored alongside weight.

1-3 months

After regaining birth weight, babies should gain about 5-7 ounces per week. If weight gain is slower than expected, continued feeding support and monitoring are important. Some babies are naturally smaller or gain weight more slowly, but consistently poor weight gain needs evaluation for feeding issues, reflux, allergies, or other medical causes.

3-6 months

Weight gain of 3-5 ounces per week is expected. If your baby continues to gain slowly, your pediatrician may investigate further with blood tests or other evaluations. Growth chart trends are more important than individual measurements.

6-12 months

With solid foods and continued milk feeding, weight gain should be steady. Babies who were slow to gain weight early may catch up, or may follow a lower growth curve consistently, which can be their normal pattern.

What to Tell Your Pediatrician

  • Describe when you first noticed slow weight regain in newborns and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if baby has not regained birth weight by 2 weeks.
  • Mention if weight gain is slower than 4-5 ounces per week in the first 3 months.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

What Should You Do?

When to take action

Probably normal when...
  • Gradual weight regain that reaches birth weight by 10-14 days
  • Some babies regain slightly slower but are feeding well and producing adequate diapers
  • Steady weight gain after birth weight is regained
Mention at your next visit when...
  • Baby has not regained birth weight by 2 weeks
  • Weight gain is slower than 4-5 ounces per week in the first 3 months
  • You are concerned about your milk supply or feeding effectiveness
Act now when...
  • Significant weight loss continuing after the first week, or baby not regaining any weight by 2 weeks
  • Baby shows signs of dehydration: fewer than 6 wet diapers per day, sunken fontanelle, dry mouth, excessive sleepiness, or lethargy

What You Can Do at Home

  • Keep track of when you notice slow weight regain in newborns — noting the time of day, duration, and any triggers can help your pediatrician.
  • Remember that gradual weight regain that reaches birth weight by 10-14 days — this is generally within the range of normal.
  • At 0-1 month, focus on observation rather than intervention unless your pediatrician advises otherwise.
  • Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
  • While monitoring at home, seek immediate care if significant weight loss continuing after the first week, or baby not regaining any weight by 2 weeks.

Normal Weight Loss After Birth

It is completely normal for newborns to lose weight in the first few days of life. Breastfed babies typically lose 5-7% of their birth weight, and formula-fed babies typically lose 3-5%. Weight loss of more than 7-10% may need intervention. Most babies regain their birth weight by 10-14 days of age.

Weight Faltering

Weight faltering (previously called "failure to thrive") describes a pattern where a baby's weight gain is significantly slower than expected, causing them to fall below the 2nd percentile for weight or drop across two or more major percentile lines on the growth chart. It is a description of a growth pattern, not a diagnosis. The most common cause in infants is inadequate caloric intake - the baby is simply not getting enough calories, whether from insufficient milk supply, feeding difficulties, or issues with solid food intake. Medical causes such as malabsorption, metabolic conditions, or chronic illness are less common but should be considered.

Newborn Not Latching

Difficulty latching is one of the most common breastfeeding challenges for new parents and newborns. Many factors can contribute, including the baby's positioning, tongue tie, flat or inverted nipples, engorgement, or the baby being sleepy or overstimulated. Most latching problems can be resolved with proper support from a lactation consultant. In the meantime, expressing colostrum or milk by hand or pump ensures the baby receives adequate nutrition.

Tool

Growth Percentile Calculator

Plot your baby's weight, length, and head circumference on WHO/CDC growth charts.

Milestone

Month-by-Month Development

Detailed monthly development guides from birth through 24 months.

Guide

When to Call the Doctor

General guide on when to call the pediatrician, visit urgent care, or go to the ER.

Frequently asked questions

Is slow weight regain in newborns normal?
Most babies regain their birth weight by 10-14 days of age. If your baby has not regained birth weight by 2 weeks, it may indicate feeding difficulties, insufficient milk supply, or other medical issues. Close follow-up with your pediatrician and a lactation consultant can help identify and address the problem.
When should I call the doctor about slow weight regain in newborns?
Significant weight loss continuing after the first week, or baby not regaining any weight by 2 weeks Baby shows signs of dehydration: fewer than 6 wet diapers per day, sunken fontanelle, dry mouth, excessive sleepiness, or lethargy
When is slow weight regain in newborns normal?
Gradual weight regain that reaches birth weight by 10-14 days Some babies regain slightly slower but are feeding well and producing adequate diapers Steady weight gain after birth weight is regained
What causes slow weight regain in newborns?
Most babies regain their birth weight by 10-14 days of age. If your baby has not regained birth weight by 2 weeks, it may indicate feeding difficulties, insufficient milk supply, or other medical issues. Close follow-up with your pediatrician and a lactation consultant can help identify and address the problem. Common explanations include: Gradual weight regain that reaches birth weight by 10-14 days. Some babies regain slightly slower but are feeding well and producing adequate diapers.
What should I mention to my pediatrician about slow weight regain in newborns?
You should mention slow weight regain in newborns at your next visit if: Baby has not regained birth weight by 2 weeks. Weight gain is slower than 4-5 ounces per week in the first 3 months. You are concerned about your milk supply or feeding effectiveness.
Is slow weight regain in newborns normal at 0-1 month?
If your baby has not regained birth weight by 2 weeks, your pediatrician will want to evaluate feeding. Common causes include poor latch, tongue tie, insufficient milk supply, sleepy feeding, or underlying medical conditions. Your pediatrician may recommend more frequent weight checks, feeding evaluation, and possibly supplementation with expressed breast milk or formula while the underlying cause is addressed. Working with a lactation consultant is highly recommended. Adequate wet diapers (at least 6 per day after day 4) and stool output are monitored alongside weight.
Is slow weight regain in newborns normal at 1-3 months?
After regaining birth weight, babies should gain about 5-7 ounces per week. If weight gain is slower than expected, continued feeding support and monitoring are important. Some babies are naturally smaller or gain weight more slowly, but consistently poor weight gain needs evaluation for feeding issues, reflux, allergies, or other medical causes.
Should I go to the ER for slow weight regain in newborns?
Seek emergency care if significant weight loss continuing after the first week, or baby not regaining any weight by 2 weeks, or if baby shows signs of dehydration: fewer than 6 wet diapers per day, sunken fontanelle, dry mouth, excessive sleepiness, or lethargy. When in doubt, call your pediatrician's after-hours line for guidance.
Does slow weight regain in newborns go away on its own?
In many cases, slow weight regain in newborns resolves on its own, especially when gradual weight regain that reaches birth weight by 10-14 days. By 6-12 months, with solid foods and continued milk feeding, weight gain should be steady. Babies who were slow to gain weight early may catch up, or may follow a lower growth curve consistently, which can be their normal pattern.
AAPWHO

References

  1. [1]American Academy of Pediatrics. Weight Gain and Nutrition. HealthyChildren.org. AAP
  2. [2]World Health Organization. Child Growth Standards. WHO

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Slow Weight Regain in Newborns.

Things to mention

  • Describe when you first noticed slow weight regain in newborns and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if baby has not regained birth weight by 2 weeks.
  • Mention if weight gain is slower than 4-5 ounces per week in the first 3 months.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

Observations to share

  • Baby has not regained birth weight by 2 weeks
  • Weight gain is slower than 4-5 ounces per week in the first 3 months
  • You are concerned about your milk supply or feeding effectiveness

Urgent signs to report immediately

  • Significant weight loss continuing after the first week, or baby not regaining any weight by 2 weeks
  • Baby shows signs of dehydration: fewer than 6 wet diapers per day, sunken fontanelle, dry mouth, excessive sleepiness, or lethargy

My notes

From ismybabyalright.com — free, evidence-based baby health guides

All content follows our editorial policy and is reviewed against published clinical guidelines.

2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members

Related Resources

Well-Baby Visit PrepGrowth Spurts TimelineGrowth Percentile CalculatorBaby Tracker

Bottom line

Most cases of slow weight regain in newborns are normal. Talk to your pediatrician if significant weight loss continuing after the first week, or baby not regaining any weight by 2 weeks.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

Share:FacebookX

Was this page helpful?

Related Medical Concerns

Normal Weight Loss After Birth

It is completely normal for newborns to lose weight in the first few days of life. Breastfed babies typically lose 5-7% of their birth weight, and formula-fed babies typically lose 3-5%. Weight loss of more than 7-10% may need intervention. Most babies regain their birth weight by 10-14 days of age.

Weight Faltering

Weight faltering (previously called "failure to thrive") describes a pattern where a baby's weight gain is significantly slower than expected, causing them to fall below the 2nd percentile for weight or drop across two or more major percentile lines on the growth chart. It is a description of a growth pattern, not a diagnosis. The most common cause in infants is inadequate caloric intake - the baby is simply not getting enough calories, whether from insufficient milk supply, feeding difficulties, or issues with solid food intake. Medical causes such as malabsorption, metabolic conditions, or chronic illness are less common but should be considered.

Newborn Not Latching

Difficulty latching is one of the most common breastfeeding challenges for new parents and newborns. Many factors can contribute, including the baby's positioning, tongue tie, flat or inverted nipples, engorgement, or the baby being sleepy or overstimulated. Most latching problems can be resolved with proper support from a lactation consultant. In the meantime, expressing colostrum or milk by hand or pump ensures the baby receives adequate nutrition.

My Baby's Head Shape Looks Abnormal

Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.

Achondroplasia (Dwarfism) in Babies

Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.

Adenoid Hypertrophy and Breathing

Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.