Low Birth Weight

Low birth weight (LBW) is defined as a birth weight of an infant between 1,500 and 2,500 grams (3 pounds 5 ounces – 5 pounds 8 ounces). Very low birth weight (VLBW) refers to infants born between 1,000 and 1,500 grams (2 pounds 3 ounces – 3 pounds 5 ounces).

LBW/VLBW is either the result of preterm birth (commonly defined as younger than 37 weeks of gestation) or of the infant being small for gestational age (a slow prenatal growth rate), or a combination of both. Additionally, LBW/VLBW can co-occur with other conditions such as Fetal Alcohol Syndrome, Congenital Heart Disease, or Failure to Thrive. LBW/VLBW is caused primarily by maternal factors, such as maternal disease or infection, smoking, alcohol and drug use, problems with the uterus or placenta, stress, and poor nutrition. Adoptive families can’t go back and change these factors, but they can strive to provide the best possible nourishment and nurturing environment for a LBW/VLBW child to grow.


LBW/VLBW is an important predictor of newborn health and survival and is associated with a higher risk of infant and childhood mortality. It is important that LBW/VLBW infants and children have their growth closely monitored by a pediatrician.

Special growth charts exist for infants born prematurely with low or very low birth weight. In order to use these growth charts, an adjustment will need to be made for gestational age. This adjustment requires knowing how many weeks premature a child was born.

If a child is assessed to have low birth weight the following growth charts may be used by a health care professional. These charts provide context and instructions for use.

Low Birth Weight – Girls

Low Birth Weight – Boys

If a child is assessed to have very low birth weight the following growth charts may be used by a health care professional. These charts provide context and instructions for use.

Very Low Birth Weight – Girls

Very Low Birth Weight – Boys

Many adoptive families may not have the benefit of knowing their child’s birth weight. Depending on a child’s situation, the birth weight may have been estimated by physician at the institution or omitted from their records altogether. Under such circumstances, it is important that the child be thoroughly assessed by a pediatrician at the initial post-adoption check-up <link to page>.

Feeding Low Birth Weight Babies

Feeding LBW/VLBW babies can be challenging. They can easily fall into a cycle of not getting enough to eat, becoming weaker, and as a result becoming even harder to feed. LBW/VLBW babies are at risk of malnutrition. In addition, LBW/VLBW babies may require more calorically dense feedings than full terms infants in order to grow.

Potential Problems:

Potential Solutions:

Work with your pediatrician or a pediatric speech therapist to determine the best solution(s) for your child.

Low Birth Weight Implications beyond Infancy

Many adopted children are past infancy when they arrive home. And so, many families may not know if their child had a low or very low weight at birth. If a child is known to have been LBW/VLBW, it is important that parents consider a child’s adjusted age when weaning or introducing complementary (solid) foods. Download a handout with instructions on how to calculate adjusted age. If you’re unable to determine the adjusted age, talk with your pediatrician to determine when is appropriate to introduce new foods and textures to your child.

LBW/VLBW is associated with inhibited growth and cognitive development, and chronic diseases later in life. As a toddler or in childhood, LBW/VLBW may affect your child in several ways:

It is important to work with a team of professionals – pediatrician, nutritionist, occupational therapist, psychologist, etc. – to determine solutions for addressing your child’s specific needs.

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