Prenatal polychlorinated biphenyl exposure is associated with decreased gestational length but not birth weight: archived samples from the Child Health and Development Studies pregnancy cohort

Table 2 Distribution of maternal PCB concentrations

Exposure category⁺	No.	Percentile distributions			Mean ± SD	Min	Max
		25^th	50^th	75^th
∑PCB_total ¹	578	2.37	2.96	3.82	3.30 ± 1.53	0.57	12.29
∑PCB_mono ²	578	0.52	0.68	0.92	0.81 ± 0.52	0.13	6.82
∑PCB_di ³	578	1.57	2.00	2.60	2.23 ± 1.05	0.40	8.98
∑PCB_tri ⁴	578	0.18	0.24	0.32	0.26 ± 0.15	0.02	1.90
∑PCB_1b ⁵	578	0.11	0.15	0.20	0.17 ± 0.09	0.02	0.83
∑PCB_2b ⁶	578	0.56	0.72	0.96	0.82 ± 0.44	0.17	3.85
∑PCB₃ ⁷	578	1.08	1.37	1.77	1.51 ± 0.66	0.23	5.29
PCB66	578	0.05	0.08	0.13	0.15 ± 0.23	0.01	2.05
PCB 74	578	0.12	0.17	0.24	0.20 ± 0.17	0.01	3.07
PCB 99	578	0.12	0.18	0.25	0.21 ± 0.15	0.01	1.18
PCB 118	579	0.31	0.40	0.53	0.46 ± 0.26	0.08	2.47
PCB 138	579	0.45	0.57	0.77	0.66 ± 0.36	0.13	3.23
PCB 153	579	0.50	0.65	0.85	0.73 ± 0.35	0.14	2.95
PCB 170	578	0.10	0.14	0.19	0.16 ± 0.09	0.01	0.72
PCB 180	579	0.33	0.44	0.56	0.47 ± 0.2	0.08	1.71
PCB 187	578	0.11	0.15	0.20	0.09 ± 0.09	0.02	0.83
PCB 194	459	0.06	0.08	0.11	0.09 ± 0.05	0.06	0.48
PCB 203	578	0.06	0.09	0.13	0.10 ± 0.08	0.01	1.27
FT4 (ng/dL)	600	1.13	1.23	1.38	1.26 ± 0.21	0.76	2.46
TSH (μIU/mL)	600	0.86	1.29	1.92	1.53 ± 1.16	0.005	12.55

⁺All PCBs are in units of ng/mL.
¹PCB congeners summed into PCB_total: all congeners with LOQ >90% except PCB₁₉₄ due to large number of missing values.
²PCB congeners summed into PCB_mono: 66, 74, 118.
³PCB congeners summed into PCB_di: 99, 138, 153, 170, 180.
⁴PCB congeners summed into PCB_tri: 187, 203.
⁵PCB congeners summed into PCB_1b: 187.
⁶PCB congeners summed into PCB_2b: 138, 170.
⁷PCB congeners summed into PCB₃: 99, 153, 180, 203.
^#LODs were different for the two labs; the most conservative LODs are reported in the table (from the MSSM lab, n = 120). LODs for the ECL (n = 460) range from 0.01 to 0.03, with 99% of samples above LODS for the various congeners. LODs are reported in ng/mL.

ISSN: 1476-069X