Low birth weight

Low birth weight babies may have health risks

A low birth weight baby was born weighing less than 2,500 grams (5 pounds, 8 ounces). On this portal, low birth weight is limited to singletons (single births, as opposed to twins, triplets, etc.) that were born at or above full-term (37 completed weeks of pregnancy or more).

A very low birth weight baby weighs less than 1,500 grams (3 pounds, 5 ounces), regardless of length of pregnancy.

A baby can be born at a low birth weight because the baby was born too soon, but the data shown here measure low birth weight only among babies who were born full-term. Very low birth weight (at the bottom of the page) includes all babies, born full-term or premature. Compared to infants of normal weight, low birth weight infants may have more health problems.

Low birth weight infants may become sick during the first weeks of life, develop infections, or have longer-term health complications such as delayed motor and social development or learning disabilities. Infant mortality rates are much higher for low birth weight infants than for infants of normal weight.


Full-term low birth weight births in Minnesota

 
 
Limited to full-term (37+ weeks), singleton births. * Change in gestational age definition beginning in 2012. Source: Minnesota Center for Health Statistics. 

In Minnesota, full-term, low-weight births are below levels in the U.S. Among 2018 singleton full-term births in Minnesota, 1.9% were born low birth weight, which was about 1,100 babies.

The proportion of low birth weight births in Minnesota is consistently below the U.S. national average. In 2018, 1.9% of Minnesota full-term singleton births were born at a low birth weight, compared to 2.5% nationally.


Full-term low birth weight births in Minnesota by mother's race/ethnicity

 
 
Limited to full-term (37+ weeks), singleton births. Categories are non-Hispanic unless noted. Data are for 2014-2018. Source: Minnesota Center for Health Statistics.

There are racial and ethnic inequities in low birth weight babies born in Minnesota. Compared to the average rate of prematurity, a mother is more likely to have a low birth weight baby if she identifies as: Black or African American, Asian or Pacific Islander, or American Indian.


Full-term low birth weight births in Minnesota by mother's age

 
 
Limited to full-term (37+ weeks), singleton births. Data are for 2014-2018. Source: Minnesota Center for Health Statistics.

In Minnesota, teens and women over age 40 are more likely to have a low birth weight baby (among full-term, singleton births)  compared to the average for all Minnesota mothers.


Very low birth weight births in Minnesota

 
 
Limited to singleton births. Source: Minnesota Center for Health Statistics.

Among 2018 singleton births in Minnesota, 0.9% were born with very low birth weight, which was about 550 babies. This chart showing very low birth weight includes babies born after any length of gestation, unlike the charts above that are only for full term births.

The proportion of very low birth weight births in Minnesota is consistently below the U.S. national average. In 2018, 0.9% of Minnesota singleton births were born at a low birth weight, compared to 1.1% nationally.

Some women are at greater risk of delivering a low birth weight baby

Some of the following things make a low birth weight baby more likely:

  • Inadequate weight gain during pregnancy
  • Placenta problems
  • Smoking or drinking alcohol during pregnancy

Other possible risk factors:

  • A mother's age and income level:
    • Teenagers and women older than 35 years
    • Low income
  • Stress
  • Exposure to air pollution
  • Exposure to drinking water contaminated with lead

Last updated June 2020.