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. Author manuscript; available in PMC: 2016 Nov 1.
Published in final edited form as: Reprod Toxicol. 2015 Jul 10;57:183–189. doi: 10.1016/j.reprotox.2015.07.069

Table 4.

Changes in infant weight, length, head circumference, and gestational age associated with interquartile range (IQR) increases in mean whole pregnancy exposures.

All subjects Term births
IQR (ng/µg) N β (95% CI) p N β (95% CI) p
Weight, gramsa
Perchlorateb 2.62 107 −63.7 (−171.5, 44.1) 0.24 81 −68.0 (−189.2, 53.2) 0.27
Thiocyanate 1026 107 −27.3 (−92.4, 37.8) 0.41 81 −23.5 (−93.2, 46.3) 0.51
Nitrate 25,059 107 6.6 (−122.1, 135.3) 0.92 81 85.3 (−106.1, 276.7) 0.38
PECc 3.38 107 20.5 (−139.9, 180.9) 0.80 81 9.5 (−186.6, 205.7) 0.92
Iodide 141 107 32.9 (−58.5, 124.2) 0.48 81 30.5 (−68.0, 129.1) 0.54
Length, cm
Perchlorate 2.62 107 −0.06 (−0.91, 0.79) 0.89 81 0.03 (−0.96, 1.01) 0.96
Thiocyanate 1026 107 −0.17 (−0.68, 0.34) 0.51 81 −0.05 (−0.61, 0.51) 0.85
Nitrate 25,059 107 −0.12 (−1.13, 0.89) 0.82 81 0.14 (−1.40, 1.69) 0.86
PEC 3.38 107 0.09 (−1.17, 1.36) 0.88 81 0.07 (−1.50, 1.65) 0.93
Iodide 141 107 0.15 (−0.57, 0.87) 0.68 81 0.15 (−0.64, 0.95) 0.70
Head circ., cm
Perchlorate 2.62 105 −0.32 (−0.66, 0.01) 0.06 80 −0.38 (−0.74, −0.03) 0.03
Thiocyanate 1026 105 0.05 (−0.15, 0.26) 0.60 80 0.08 (−0.13, 0.29) 0.46
Nitrate 25,059 105 0.07 (−0.33, 0.47) 0.73 80 0.02 (−0.56, 0.61) 0.92
PEC 3.38 105 0.48 (−0.01, 0.97) 0.06 80 0.38 (−0.20, 0.96) 0.19
Iodide 141 105 0.03 (−0.26, 0.31) 0.86 80 −0.00 (−0.30, 0.29) 0.98
Gestational age, weeksd
Perchlorate 2.62 104 0.34 (−0.12, 0.79) 0.15 80 0.12 (−0.12, 0.36) 0.32
Thiocyanate 1026 104 0.02 (−0.21, 0.25) 0.87 80 −0.02 (−0.13, 0.10) 0.76
Nitrate 25,059 104 −0.16 (−0.73, 0.42) 0.59 80 0.07 (−0.33, 0.47) 0.73
PEC 3.38 104 −0.46 (−1.10, 0.18) 0.15 80 −0.19 (−0.55, 0.17) 0.30
Iodide 141 104 0.08 (−0.30, 0.47) 0.67 80 0.00 (−0.20, 0.19) 0.97
a

Weight, length, and head circumference models include maternal smoking, nulliparity, infant gender, and gestational age.

b

Perchlorate, thiocyanate, nitrate, and iodide concentrations are creatinine-adjusted (ng/µg creatinine).

c

PEC: perchlorate equivalence concentration (molar concentrations)=(perchlorate)+(nitrate/240)+(thiocyanate/15).

d

Gestational age models include maternal race/ethnicity and paternal employment status; all models weighted by number of urine samples per subject.