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• Related Issues
• Specifics

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Summary

Birth weight is the first weight of your baby, taken just after he or she is born. A low birth weight is less than 5.5 pounds. A high birth weight is more than 8.8 pounds.

A low birth weight baby can be born too small, too early (premature), or both. This can happen for many different reasons. They include health problems in the mother, genetic factors, problems with the placenta, and drug use by the mother.

Some low birth weight babies may be more at risk for certain health problems. Some may become sick in the first days of life or develop infections. Others may suffer from longer-term problems such as delayed motor and social development or learning disabilities.

High birth weight babies are often big because the parents are big, or the mother has diabetes during pregnancy. These babies may be at a higher risk of birth injuries and problems with blood sugar.

Centers for Disease Control and Prevention

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

Related Issues

• 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 (National Institutes of Health)
• ClinicalTrials.gov: Infant, Small for Gestational Age (National Institutes of Health)
• ClinicalTrials.gov: Large for Gestational Age (National Institutes of Health)

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

• Article: Association of Birth Weight With Foveolar Thickness in Adulthood: Results From...
• Article: Infant Formula Based on Milk Fat Affects Immune Development in Both...
• Article: The influence of maternal blood glucose during pregnancy on weight outcomes...
• Birth Weight -- see more articles

Find an Expert

• Eunice Kennedy Shriver National Institute of Child Health and Human Development 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