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Low Birth Weight and Very Low Birth Weight

Narrative

Infants born at low birth weight (less than 2,500 grams or 5.5 pounds) and especially very low birth weight (less than 1,500 grams or 3.25 pounds) are more likely to experience physical and developmental health problems and to die in the first year of life than are infants of normal birth weight. The developmental problems of low birth weight infants exact a significant emotional and financial toll, often requiring increased levels of medical, educational, and parental care. The majority of very low birth weight infants are born prematurely, whereas those born at moderately low birth weight include a mix of prematurity as well as fetal growth restriction that may be related to factors such as maternal hypertension, tobacco smoke exposure, or inadequate weight gain during pregnancy.1

In 2010, 8.15 percent of infants were born at low birth weight, including 1.45 percent who were born at very low birth weight. After steady increases, rates of low and very low birth weight peaked in 2006 at 8.26 and 1.49 percent, respectively, and have declined only slightly since then. Reasons for the increase in low birth weight may mirror those behind increases in prematurity, including increases in obstetric interventions, maternal age, and fertility treatments.2 A rise in multiple births, which increase with maternal age and fertility treatments and are at high risk of low birth weight, has strongly influenced the rise in low birth weight; however, rates of low birth weight have also increased for singleton births.2

Infants born to non-Hispanic Black women have the highest rates of low and very low birth weight (13.53 and 2.98 percent, respectively), levels that are about two or more times greater than for infants born to women of other racial and ethnic groups. For example, low and very low birth weight rates among non-Hispanic Whites were 7.14 and 1.16 percent, respectively. Given their heightened risk of death, the large disparity in very low birth weight is a major contributor to the mortality gap between non-Hispanic Black and White infants.3

1 March of Dimes. Low Birth Weight. Accessed: July 2, 2012.

2 Martin JA, Hamilton BE, Sutton PD, Ventura SJ, et al. Births: Final data for 2006. National vital statistics reports; vol 57 no 7. Hyattsville, MD: National Center for Health Statistics. 2009.

3 Wise PH. The anatomy of a disparity in infant mortality. Annu Rev Public Health. 2003;24:341-62.

Graphs

This image is described in the Data section.

infant low birthweight by maternal race graph

This image is described in the Data section.

infant low birthweight by maternal race graph

Data

Low and Very Low Birth Weight, 1990-2010
Year Percent of Live Births
Low Birth Weight, <2,500 grams Very Low Birth Weight, <1,500 grams
Sources: Martin, JA, Hamilton BE, Ventura SJ, Osterman, MK, Wilson, EC, Mathews, TJ. Births: Final data for 2010. National vital statistics reports; vol 61 no 1. Hyattsville, MD: National Center for Health Statistics. 2012. Martin JA, Hamilton BE, Ventura SJ, et al. Births: Final data for 2009. National vital statistics reports; vol 60 no 1. Hyattsville, MD: National Center for Health Statistics. 2011.
1990 6.97 1.27
1995 7.32 1.35
2000 7.57 1.43
2005 8.19 1.49
2010 8.15 1.45
Low and Very Low Birth Weight, by Maternal Race/Ethnicity,* 2010
Race/Ethnicity Percent of Live Births
Low Birth Weight, <2,500 Grams Very Low Birth Weight, <1,500 Grams
*Includes Hispanics.
†Separate data for Asians and Native Hawaiians and Other Pacific Islanders not available.
Source: Martin, JA, Hamilton BE, Ventura SJ, Osterman, MK, Wilson, EC, Mathews, TJ. Births: Final data for 2010. National vital statistics reports; vol 61 no 1. Hyattsville, MD: National Center for Health Statistics. 2012.
Non-Hispanic White 7.14 1.16
Non-Hispanic Black 13.53 2.98
Hispanic 6.97 1.20
American Indian/Alaska Native* 7.61 1.28
Asian/Pacific Islander*† 8.49 1.17