Intrauterine Growth Restriction (Growth Retardation): Facts & Figures

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Intrauterine growth restriction (growth retardation) occurs when an infant is born full-term (at or above 37 completed weeks of pregnancy) but of a low birth weight-- that is, a birth weight of less than 2,500 grams (or 5 pounds, 8 ounces). The traditional definition of low birth weight (LBW) includes infants born too soon (premature), too small (growth restricted) or both. Because different factors influence preterm delivery and growth restriction, limiting the definition of LBW to full-term births allows for the examination of factors influencing growth restriction. A newborn's weight at birth is closely related to its risk of early death and long-term morbidity. Compared to infants of normal weight (2,500 through 3,999 grams or 5.9 to 8.7 pounds), LBW infants may be at increased risk of perinatal morbidity, infections, and the longer-term consequences of impaired development, such as delayed motor and social development or learning disabilities.

Some risk factors for growth restriction include maternal smoking, alcohol use, poor nutrition and inadequate weight gain, stress, and domestic violence or other abuse. Because multiple births (e.g., twins or triplets) are a risk factor for growth restriction, this measure is limited to live singleton births.


Low birthweight births* in Minnesota by year

 
Year 2000 2001 2002 2003 2004 2005 2006 2007 2008
Percent 1.53% 1.60% 1.74% 1.63% 1.67% 1.65% 1.77% 1.76% 1.78%
Count 809 844 946 906 934 918 1005 991 1010

* Births are among live singleton births.

 

Annual percentage and count of low birth weight births among live singleton term births, Minnesota, 2000-2008 with U.S. low birth weight among live singleton term births, 2000-2007
*Births are among live singleton births.

The overall trend in Minnesota and in the U.S. is one of increasing low birth weight. Minnesota, at around 1.8%, is below the U.S. percentage of 2.7%.


Low birthweight births* in Minnesota by race and ethnicity categories

Year White Black Asian or Pacific Islander American Indian Hispanic (may be of any race)
2000 1.34% 3.39% 2.59% 1.43% 1.68%
2001 1.43% 3.18% 2.55% 1.80% 1.63%
2002 1.49% 3.61% 3.05% 2.97% 2.11%
2003 1.43% 3.01% 2.87% 2.00% 1.74%
2004 1.44% 2.92% 2.64% 2.53% 1.76%
2005 1.37% 3.49% 3.06% 1.74% 1.54%
2006 1.45% 3.60% 3.30% 2.23% 2.05%
2007 1.52% 3.23% 3.18% 1.88% 1.48%
2008 1.44% 3.40% 3.03% 1.67% 2.26%

* Births are among live singleton births.

 

Black and Asian or Pacific Islander infants have the highest rates of LBW. The rate of LBW among American Indian infants has been declining. Large annual changes in the LBW rate for American Indians may be due to small numbers.