Table 1: Characteristics of study participants.

CharacteristicBirth weight
<2500 g ( )2500–4000 g ( )>4000 ( ) value

Maternal age at enrollment (yrs)0.79
 18–25 ( )4 (40%)67 (31%)6 (28.5%)
 26–30 ( )4 (40%)65 (30%)6 (28.5%)
 >30 ( )2 (20%)86 (39%)9 (43%)
Maternal BMI before pregnancy0.17
 <30 ( )7 (87.5%)140 (71%)11 (55%)
 ≥30 ( )1 (12.5%)56 (29%)9 (45%)
 Mean BMI26.61 (SD = 4.8)28.4 (SD = 9.4)31.3 (SD = 12.3) 0.37
Race/ethnicity0.1
 African American ( )8 (89%)110 (51%)8 (38%)
 White ( )1 (11%)85 (39%)9 (43%)
 Other ( )0 (0%)21 (9.7%)4 (19%)
Education 0.18
 <High School HS Graduate/GED ( )6 (67%)79 (39%)9 (43%)
 Some College/College Graduate/ 3 (33%)136 (63%)12 (57%)
 Graduate education ( )
Maternal smoking 0.14
 Never smoked ( )2 (20%)120 (55%)13 (62%)
 Smoked during pregnancy ( )3 (30%)36 (17%)1 (5%)
 Quit smoking before pregnancy ( )5 (50%)62 (28%)7 (33%)
Gender of infant0.12
 Male ( )5 (50%)86 (39%)13 (62%)
 Female ( )5 (50%)132 (61%)8 (38%)
Delivery route0.75
 Vaginal ( )7 (70%)131 (61%)10 (48%)
 Caesarean section ( )3 (30%)86 (39%)11 (52%)
Gestational age at delivery in weeks0.006
 Mean (SD)37 (0.22)39 (1.11)39 (0.93)
IGF-I0.12
 ≤3rd Tertile ( )5 (50%)153 (70%)11 (52%)
 >3rd Tertile ( )5 (50%)65 (30%)10 (48%)

Numbers do not necessarily add up due to missing values.