Table 1 Comparison of Non-Participants and Participants

 Age at delivery (years)

26.7 ± 5.5

27.1 ± 5.6

27.5 ± 5.1

 Education (total years)

11.8 ± 2.8

11.9 ± 2.8

11.6 ± 2.8

 Pre-pregnancy BMI (kg/m²)

24.9 ± 4.1

25.8 ± 4.4^*

24.7 ± 3.9

 2nd trimester blood lead (μg/dL)^a

3.6 ± 2.5

3.5 ± 2.5

3.9 ± 2.8

 3rd trimester blood lead (μg/dL)^b

3.8 ± 2.7

3.7 ± 2.9

4.2 ± 3.4

 Tibia lead (μg/g)^c

4.7 ± 5.4

5.6 ± 5.8

4.9 ± 5.0

 Sex (male) n (%)

182 (51)

129 (51)

90 (60)

 Ever breastfed n (%)^d

303 (85)

224 (88)

139 (93)

 Gestational Age, weeks

38.3 ± 1.9

38.3 ± 1.5

38.5 ± 1.6

 Birth Weight, kg

3.0 ± 0.5

3.1 ± 0.4

3.2 ± 0.4^*