An infants birth weight is considered low if it is less than ________ pounds.

Birth weight is the first weight of your baby, taken just after being born. A low birth weight means that the baby is less than 5 pounds, 8 ounces. A high birth weight means that the baby is more than 8 pounds, 13 ounces.

What can cause low birth weight?

A baby with a low birth weight can be born too small, too early (premature), or both. This can happen for many different reasons. They include:

  • Health problems in the pregnant parent
  • Taking certain medicines during pregnancy
  • Substance use during pregnancy
  • Infections during pregnancy
  • Being pregnant with multiple babies
  • Problems with the placenta, the organ that brings oxygen and nutrients to the baby
  • Having small parents
  • Genetic conditions in the baby
  • Birth defects

What problems can low birth weight cause?

Babies with low birth weight may be more at risk of certain health problems. They include immediate problems, such as:

  • Breathing problems
  • Infections
  • Hypoglycemia (low blood sugar)
  • Jaundice
  • Trouble keeping warm

There is also a higher risk of longer-term problems, including:

  • Delayed motor and social development
  • Learning disabilities
  • Certain health conditions as an adult, such as heart disease, high blood pressure, diabetes, and obesity

What can cause high birth weight?

Causes of high birth weight can include:

  • Having big parents
  • Diabetes in the pregnant parent
  • Certain genetic conditions
  • Too much weight gain during pregnancy

What problems can high birth weight cause?

High birth weight can be a concern because it can make delivery of the baby difficult and raise the risk of birth injuries. The baby is at higher risk of problems with:

  • Blood sugar
  • Breathing problems
  • Jaundice

Can birth weight problems be prevented?

You may be able to prevent some birth weight problems by:

  • Getting regular checkups during pregnancy
  • Getting the right amount of nutrition and calories during pregnancy
  • Controlling your blood sugar if you have diabetes
  • Avoiding substance use during pregnancy

Start Here

  • Growth and Your Newborn (Nemours Foundation) Also in Spanish
  • Tracking Your Baby's Weight and Measurements (American Academy of Pediatrics) Also in Spanish

  • Intrauterine Growth Restriction (American Academy of Family Physicians) Also in Spanish
  • Intrauterine Growth Restriction (IUGR) (Nemours Foundation)

Specifics

  • Fetal Macrosomia (Mayo Foundation for Medical Education and Research) Also in Spanish
  • Large-for-Gestational-Age (LGA) Newborn (Merck & Co., Inc.)
  • Low Birthweight (March of Dimes Birth Defects Foundation) Also in Spanish

Statistics and Research

  • FastStats: Birthweight and Gestation (National Center for Health Statistics)

Clinical Trials

  • ClinicalTrials.gov: Infant, Low Birth Weight
    An infants birth weight is considered low if it is less than ________ pounds.
    (National Institutes of Health)
  • ClinicalTrials.gov: Infant, Small for Gestational Age
    An infants birth weight is considered low if it is less than ________ pounds.
    (National Institutes of Health)
  • ClinicalTrials.gov: Large for Gestational Age
    An infants birth weight is considered low if it is less than ________ pounds.
    (National Institutes of Health)

Journal Articles References and abstracts from MEDLINE/PubMed (National Library of Medicine)

  • Article: Ambient temperature and term birthweight in Latin American cities.
  • Article: Neonatal head circumference by gestation reflects adaptation to maternal body size:...
  • Article: Risk scores for predicting small for gestational age infants in Japan:...
  • Birth Weight -- see more articles

Find an Expert

  • Eunice Kennedy Shriver National Institute of Child Health and Human Development
    An infants birth weight is considered low if it is less than ________ pounds.
    Also in Spanish
  • KidsHealth (Nemours Foundation)
  • March of Dimes Birth Defects Foundation Also in Spanish

Patient Handouts

  • Large for gestational age (LGA) (Medical Encyclopedia) Also in Spanish
  • Neonatal weight gain and nutrition (Medical Encyclopedia) Also in Spanish
  • Small for gestational age (SGA) (Medical Encyclopedia) Also in Spanish

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An infants birth weight is considered low if it is less than ________ pounds.

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MEDICAL ENCYCLOPEDIA

  • Appropriate for gestational age (AGA)
  • Intrauterine growth restriction
  • Large for gestational age (LGA)
  • Neonatal weight gain and nutrition
  • Small for gestational age (SGA)

  • Fetal Health and Development
  • Premature Babies
  • Uncommon Infant and Newborn Problems

National Institutes of Health

The primary NIH organization for research on Birth Weight is the Eunice Kennedy Shriver National Institute of Child Health and Human Development

Other Languages

Find health information in languages other than English on Birth Weight

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Is 6 lbs considered low birth weight?

A birthweight less than 2,500 grams (5 pounds, 8 ounces) is diagnosed as low birthweight. Babies weighing less than 1,500 grams (3 pounds, 5 ounces) at birth are considered very low birthweight.

What is normal low birth weight?

'Low birth weight' (LBW) has been defined as first weight recorded within hours of birth of <2500 g. Very low birth weight (VLBW) is accepted as <1500 g and extremely low birth weight (ELBW) is <1000 g [1].

Is 5.5 pounds a small baby?

A low birth weight means that the baby is less than 5 pounds, 8 ounces. A high birth weight means that the baby is more than 8 pounds, 13 ounces.

Is 6 lbs too small for a newborn?

Low birth weight is a term used to describe babies who are born weighing less than 5 pounds, 8 ounces (2,500 grams). An average newborn usually weighs about 8 pounds. A low-birth-weight baby may be healthy even though he or she is small. But a low-birth-weight baby can also have many serious health problems.