Table 1.

Basic Characteristics of the Study Population (n = 369), Infant Growth Project, Jefferson County, Alabama, 1985–1988

	No. of Subjects	Total	%a	Mean (SD)
Infant characteristics
Female gender	179	369	48.5
Gestational age, weeks				38.2 (2.7)
Birth weight, g				3,031 (649)
Preterm birth (<37 weeks)	72	369	19.5
Small-for-gestational-ageb birth	75	369	20.3
Race/ethnicity
White	104	369	28.2
Black/African-American	265	369	71.8
Maternal characteristics
Age, years				24.2 (4.3)
Maternal education
Less than high school diploma	123	368	33.4
High school diploma	126	368	34.2
≥1 years of college	119	368	32.3
PPVT-R score				73 (12.9)
Pregnancy characteristics
Cesarean delivery	52	329	15.8
Infection during pregnancy	61	335	18.2
Antibiotics during labor	22	337	6.5
Intrapartum fever >100.4°F	6	321	1.9
Smoking during pregnancy	158	363	43.5
Alcohol drinking during pregnancy	118	369	32.0
Povertyc	226	322	70.2
Home Screening Questionnaire score				36.8 (6.2)
Child IQ score <70
Verbal IQ	47	369	12.7	84.2 (11.6)
Performance IQ	43	369	11.7	84.5 (13.4)

Abbreviations: IQ, intelligence quotient; PPVT-R, Peabody Picture Vocabulary Test–Revised; SD, standard deviation.

^aDenominators vary because of missing values for different variables; percentages may not total 100 because of rounding.

^bBelow the 10th percentile of weight-for-age based on a fetal growth standard (34).

^cFamily income below $9,600 per year.