TABLE 1

Parents’ and Children’s Characteristics Overall and According to Breastfeeding Status at 4 Months of Age and Timing of CF Introduction Among 1013 Mother-Child Pairs in the Project Viva Cohort

Overall (N = 1013)Breastfed (at Least Partly) at 4 mo (n = 704; 69%)Formula Fed (Never Breastfed or Stopped Breastfeeding) at 4 mo (n = 309; 31%)
Timing of CF IntroductionTiming of CF Introduction
<4 mo (n = 81; 12%)4–<6 mo (n = 509; 72%)≥6 mo (n = 114; 16%)<4 mo (n = 108; 35%)4–<6 mo (n = 176; 57%)≥6 mo (n = 25; 8%)
Parental characteristics
 Maternal age at enrollment, y, mean (SD)32.6 (4.8)31.8 (5.4)33.0 (4.2)34.5 (4.4)29.9 (5.6)32.2 (5.0)32.9 (5.7)
 Maternal marital status, married or cohabitating, %95919799829592
 Maternal education, college graduate, %74658388486360
 Household income >$70 000 (US) per y, %66567272526247
 Maternal prepregnancy BMI, kg/m2, mean (SD)24.4 (5.0)24.6 (4.6)23.6 (4.1)23.8 (4.3)26.2 (6.4)25.3 (5.9)27.8 (7.6)
 Paternal BMI, kg/m2, mean (SD)26.4 (3.9)26.2 (3.3)26.2 (3.9)25.5 (3.2)27.4 (5.0)27.0 (3.9)27.5 (4.7)
Child characteristics
 Female sex, %51435153465556
 Race and/or ethnicity, %
  White69537380557048
  Black or African American1222104211036
  Hispanic41032724
  Asian3034264
  Other1215111115118
 Gestational age at birth, wk, mean (SD)39.7 (1.4)39.6 (1.5)39.7 (1.4)39.8 (1.3)39.8 (1.4)39.6 (1.4)39.2 (1.7)
 Birth wt, kg, mean (SD)3.53 (0.52)3.48 (0.56)3.54 (0.51)3.60 (0.49)3.51 (0.55)3.50 (0.50)3.35 (0.61)
 Birth wt for gestational age, z score, mean (SD)0.23 (0.97)0.11 (1.01)0.25 (0.95)0.35 (0.96)0.17 (0.99)0.21 (0.99)−0.02 (0.97)
 Change in wt-for-age z score from 0 to 4 mo, SD units, mean (SD)0.35 (1.01)0.49 (1.13)0.29 (0.99)0.15 (1.05)0.56 (1.00)0.44 (0.93)0.39 (1.12)