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

04/01/1997

Low birth weight infants (babies born weighing less than 2,500 grams or 5.5 pounds) face an increased risk of physical and developmental complications and death.14 These babies account for nearly two-thirds of all neonatal deaths (deaths under 28 days of age).15

The percentage of all infants born at low birth weight declined between 1970 and 1985, from 7.9 percent to 6.8 percent (see Table HC 2.2.A). By 1995, however, that percentage had increased to 7.3 percent of all infants.16 This pattern is evident for both white and black births and across almost all age groups of mothers.

Differences by Race and Ethnicity. Low birth weight rates are consistently higher for blacks than for whites and Hispanics. In 1970, 6.9 percent of white infants and 13.9 percent of black infants born in the U.S. were low birth weight. This gap continued into the 1990s; by 1995, 13.0 percent of black infants and 6.2 percent of white infants were born at low birth weight. The rates for Hispanics have remained at or slightly below 6.3 percent between 1980 (the first year for which Hispanic data are available) and 1995.

Differences by Age of Mother. For mothers in all age groups, there was a decline in the percentage of low weight births between 1970 and 1985. Since 1985, however, that percentage increased slightly across nearly all age groups. The following trends, illustrated in Table HC 2.2.A, are particularly noteworthy:

  • Mothers under age 15 consistently have the highest rates of low weight births (see Figure HC 2.2.A). While the percentage of low weight births to mothers under age 15 improved between 1970 and 1994, the trend has not been one of consistent improvement. Instead, the percentage of low weight births to these very young mothers decreased considerably between 1970 and 1985 from 16.6 percent to 12.9 percent but then increased to 13.3 percent in 1990 and to 13.7 percent in 1994.
  • For mothers in all other age groups, rates of low weight births have stayed within 1.5 percentage points of their 1970 rate.
  • Mothers between the ages of 25 and 29 consistently have the lowest rates of low weight births.

 

Figure HC 2.2.A 
Percentage of All Births Born at Low Birth Weight, by Age of Mother:a 1994 

HC2_2A.GIF

Notes: aBefore 1979, low birth weight defined as: Infants weighing < 2,500 grams. 1979 and beyond, low birth weight defined as: Infants weighing < 2,500 grams.
Source: 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).
 

Table HC 2.2.A
Percentage of All Births Born at Low Birth Weight,a Selected Years: 1970-1995

 
     
1970
1975
1980
1985
1990
1992
1993
1994
1995d
     
 
 
 
 
 
 
 
 
 
 
Total    
7.9
7.4
6.8
6.8
7
7.1
7.2
7.3
7.3
 
  Race/Ethnicityb,c
    Black
13.9
13.2
12.7
12.7
13.3
13.3
13.3
13.2
13
    White
6.9
6.3
5.7
5.7
5.7
5.8
6
6.1
6.2
    Hispanic
--
--
6.1
6.2
6.1
6.1
6.2
6.3
6.3
 
  Age of Mother
    Under 15
16.6
14.1
14.6
12.9
13.3
13.2
13.5
13.7
--
    15-19
10.5
10
9.4
9.3
9.3
9.3
9.2
9.3
--
    20-24
7.4
7.1
6.9
6.9
7.1
7.1
7.2
7.3
--
    25-29
6.9
6.1
5.8
5.9
6.2
6.2
6.4
6.4
--
    30-34
7.5
6.8
5.9
6.1
6.4
6.5
6.7
6.7
--
    35-49
8.8
8.4
7.2
7.1
7.4
7.8
8.1
8.2
--
 
Notes: aBefore 1979, low birth weight defined as: Infants weighing < 2,500 grams (< 5.5 pounds). 1979 and beyond, low birth weight defined as: Infants weighing < 2,500 grams (<5.5 pounds).  
bPercentages are based on the race and ethnicity of the mother.  
cPercentage 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 report Hispanic origin 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.  
dData for 1995 are preliminary. 

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. 1970 data from: National Center for Health Statistics, Health, United States, 1982, Table 24; 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. 1982; 1985 data from: National Center for Health Statistics: Vital Statistics of the United States, 1985, Vol. I, Natality. DHHS Pub. No. (PHS) 81-1113. Public Health Service; Washington. 1988. Table 1-81. 1990 data from: Monthly Vital Statistics Report, Vol. 41, No. 9(s), February, 1993, Tables 13 and 26; 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). 1995 preliminary data from: Rosenberg, H.M., Ventura, S.J., Maurer, J.D., Heuser, R.L., Freedman, M.A. Births and Deaths: United States, 1995. Monthly Vital Statistics Report, Vol 45, No. 3, Supplement 2. Hyattsville, Maryland: National Center for Health Statistics. 1996. 

 

14 Disorders relating to short gestation and unspecified low birth weight were the second leading cause of death to infants in 1995 as reported in Rosenberg, H.M., Ventura, S.J., Maurer, J.D., Heuser, R.L., and M.A. Freedman. "Births and Deaths: United States, 1995." Monthly Vital Statistics Report. Vol. 45, No. 3 (Supplement 2). Hyattsville, Maryland: National Center for Health Statistics. 1996.

15 Ventura, S.J., Martin, J.A., Mathews, T.J., Clarke, S.C. "Advance Report of Final Natality Statistics, 1994." Monthly Vital Statistics Report, Vol. 44, No. 11 (S). Hyattsville, Maryland: National Center for Health Statistics, 1996.

16 Data for 1995 are preliminary.
 
 

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