Trends in the Well-Being of America's Children and Youth, 1997. HC 2.2.b Very low birth weight

04/01/1997

Very low birth weight infants (babies born weighing less than 1,500 grams, or 3.3 pounds) are at particularly high risk of severe physical and developmental complications and death. Advances in medical technology in recent years have made it possible for increasing numbers of very low weight infants to survive.

The percentage of infants born at very low birth weight has remained constant for the last 24 years (see Table HC 2.2.B). Between 1970 and 1989 (not shown), 1.2 percent of all infants were classified as very low birth weight.17 The proportion then increased slightly to 1.3 percent, where it has remained from 1990 to 1994.

Differences by Race and Ethnicity. The percentage of babies born at very low birth weight varies by race and ethnicity (see Table HC 2.2.B). For whites, the percentage of very low weight births has remained at or about 1.0 percent from 1970 through 1994. For blacks, the percentage of very low birth weight babies increased from 2.4 percent in 1970 to 3.0 percent by 1992, where it has remained through 1994. In contrast, the percentage of low birth weight babies (as distinct from "very low") decreased for both blacks and whites from 1970 to the mid-1980s, then increased (see Table HC 2.2.A in the previous discussion). The percentage of very low weight births among Hispanics was 1.0 percent for the years shown between 1980 and 1992, and 1.1 percent in 1993 and 1994.

Differences by Age of Mother. Age of mother appears to be an important factor in the likelihood of very low birth weight, particularly at the youngest ages. The percentage of very low weight infants born to mothers under age 15 has increased since 1975, reaching its highest proportion in 1993 at 3.6 percent, and then decreasing slightly to 3.4 percent by 1994. The percentage of very low weight births among mothers age 15 to 19 is lower than the proportion of such births to their younger counterparts but remains slightly higher than the proportion observed for women age 20 and older.
 
 

Table HC 2.2.B  
Percentage of All Births Born at Very Low Birth Weight,a Selected Years: 1970-1994

 
     
1970
1975
1980
1985
1990
1992
1993
1994
     
 
 
 
 
 
 
 
 
Total    
1.2
1.2
1.2
1.2
1.3
1.3
1.3
1.3
Race/Ethnicityb,c
    White
1
0.9
0.9
0.9
1
1
1
1
    Black
2.4
2.4
2.5
2.7
2.9
3
3
3
    Hispanic
 
 
1
1
1
1
1.1
1.1
Age of Mother
    Under 15
 
3.1
3.4
3.1
3.2
3.1
3.6
3.4
    15-19
 
1.8
1.7
1.8
1.8
1.8
1.8
1.7
    20-24
 
1.1
1.1
1.2
1.3
1.3
1.3
1.3
    25-29
 
0.9
1
1
1.1
1.1
1.1
1.2
    30-34
 
1
1
1.1
1.2
1.2
1.2
1.2
    35-49
 
1.2
1.2
1.3
1.4
1.5
1.5
1.6
 
Notes: aBefore 1979, very low birth weight defined as: < 1,500 grams, 1979 and beyond, very low birth weight defined as: Infants Weighing < 1,500 grams.  
bPercentages are based on the race and ethnicity of the mother.  
cPercentage very low birth weight by ethnicity are not available before 1980. Birth figures for Hispanic infants in 1980 are based on data from 22 States which reported Hispanic origin of the mother on the birth certificate; 23 States and the District of Columbia in 1985; 48 States and the District of Columbia in 1990; 49 States and the District of Columbia in 1992; and 50 States and the District of Columbia in 1993 and 1994.  

Sources: National Center for Health Statistics. Health, United States, 1995. Hyattsville, Maryland: Public Health Service. 1996. Table 11 for totals and race/ethnicity breaks for 1970-1993. 1975 data from: Vital Statistics of the U.S., 1975, Table 1-37; 1980 data from: Monthly Vital Statistics Report, Vol. 31 No. 8, Supplement. Hyattsville, Maryland: National Center for Health Statistics. 1982 (table 13); 1985 data from: Monthly Vital Statistics Report, Vol. 36 No.4, Supplement. Hyattsville, Maryland: National Center for Health Statistics. 198 (table 17); 1990 data from: Monthly Vital Statistics Report, Vol. 41, No. 9, Supplement. Hyattsville, Maryland: National Center for Health Statistics. 1993 (table 13); 1992 data from: Ventura, S.J., Martin, J.A., Taffel, S.M., Mathews, T.J. and Clarke S.C. "Advance Report of Final Natality Statistics, 1992." Monthly Vital Statistics Report, Vol. 43, No. 5, Supplement. Hyattsville, Maryland: National Center for Health Statistics. 1994 (tables 24 and 44); 1993 data from: Ventura, S.J., Martin, J.A., Taffel, S.M., Mathews, T.J. and Clarke S.C. "Advance Report of Final Natality Statistics, 1993." Monthly Vital Statistics Report, Vol. 44, No. 3, Supplement. Hyattsville, Maryland: National Center for Health Statistics. 1995 (tables 24 and 44); 1994 data from: Ventura, S.J., Martin, J.A., Mathews, T.J. and Clarke S.C. "Advance Report of Final Natality Statistics, 1994." Monthly Vital Statistics Report, Vol. 44, No. 11, Supplement. Hyattsville, Maryland: National Center for Health Statistics. 1996 (tables 24 and 44).

 

17 Data for individual years indicate that the rate remained at 1.2 percent through 1989 (not shown).
 
 

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