Table 1:

Maternal and child characteristics by in utero and postnatal lead levels (N=146)

Variable	Level	2nd Trimester Leada			3rd Trimester Leada			Postnatal Leada
		N	Median (IQR) or p	p-valueb	N	Median (IQR) or p	p-valueb	N	Median (IQR) or p	p-valueb
Maternal education	dHS diploma	13	0.024 (0.018)	0.26	13	0.026 (0.013)	0.087	13	0.023 (0.026)	0.077
	Some college	61	0.027 (0.037)		64	0.033 (0.047)		65	0.030 (0.029)
	≥Bachelor’s Degree	62	0.022 (0.026)		65	0.031 (0.034)		65	0.024 (0.030)
Household income	<$20,000	9	0.024 (0.011)	0.98	9	0.033 (0.030)	0.89	9	0.027 (0.021)	0.49
	$20,000-<$40,000	24	0.026 (0.032)		25	0.032 (0.033)		26	0.028 (0.031)
	$40,000-<$80,000	40	0.029 (0.024)		44	0.035 (0.040)		45	0.032 (0.036)
	$80,000-<$ 100,000	25	0.021 (0.030)		25	0.027 (0.041)		24	0.022 (0.024)
	≥$100,000	23	0.021 (0.028)		24	0.032 (0.034)		24	0.025 (0.028)
	Refused to Answer	15	0.020 (0.053)		15	0.028 (0.045)		15	0.022 (0.046)
Married	No	36	0.028 (0.051)	0.089	38	0.034 (0.066)	0.14	39	0.034 (0.040)	0.063
	Yes	100	0.023 (0.026)		104	0.030 (0.033)		104	0.024 (0.026)
Location of residence	Suburban	85	0.021 (0.026)	0.024	88	0.027 (0.030)	0.005	89	0.022 (0.028)	0.003
	Urban	51	0.028 (0.039)		54	0.041 (0.056)		54	0.033 (0.027)
Maternal age at birth	---	136	0.056	0.52	142	0.094	0.27	143	0.054	0.52
Maternal BMI at first prenatal visit	---	135	−0.014	0.87	141	0.031	0.72	142	0.064	0.45
Mother Atopic	No	62	0.025 (0.037)	0.79	64	0.032 (0.047)	0.69	66	0.024 (0.035)	0.55
	Yes	71	0.024 (0.026)		75	0.030 (0.033)		74	0.029 (0.023)
Prenatal antibiotic use	No	54	0.023 (0.027)	0.37	57	0.033 (0.040)	0.74	57	0.024 (0.027)	0.16
	Yes	77	0.025 (0.032)		78	0.031 (0.044)		79	0.029 (0.032)
Prenatal antifungal use	No	108	0.026 (0.029)	0.20	112	0.033 (0.045)	0.18	113	0.029 (0.031)	0.097
	Yes	23	0.024 (0.030)		23	0.026 (0.025)		23	0.021 (0.022)
Mother smoked during pregnancy	No	127	0.024 (0.028)	0.33	133	0.031 (0.038)	0.41	134	0.027 (0.028)	0.84
	Yes	9	0.035 (0.045)		9	0.042 (0.075)		9	0.024 (0.033)
ETS during pregnancy	No	107	0.024 (0.026)	0.13	112	0.030 (0.037)	0.18	112	0.027 (0.028)	0.34
	Yes	29	0.035 (0.044)		30	0.039 (0.059)		31	0.027 (0.033)
Prenatal indoor pets	No	76	0.029 (0.042)	0.058	80	0.038 (0.048)	0.019	82	0.028 (0.030)	0.19
	Yes	60	0.021 (0.020)		62	0.026 (0.024)		61	0.024 (0.027)
Year House was Built	1980 or after	26	0.023 (0.030)	0.40	28	0.026 (0.036)	0.16	28	0.022 (0.024)	0.099
	Before 1980	104	0.024 (0.028)		108	0.032 (0.038)		109	0.027 (0.031)
First born child	No	79	0.025 (0.019)	0.90	83	0.032 (0.032)	0.64	85	0.027 (0.027)	0.81
	Yes	57	0.024 (0.033)		59	0.030 (0.051)		58	0.027 (0.031)
Season of birth	Winter	29	0.022 (0.022)	0.52	30	0.029 (0.035)	0.65	31	0.029 (0.033)	0.88
	Spring	34	0.029 (0.048)		36	0.034 (0.058)		37	0.025 (0.039)
	Summer	35	0.021 (0.028)		37	0.030 (0.032)		37	0.024 (0.026)
	Fall	38	0.026 (0.032)		39	0.032 (0.045)		38	0.029 (0.021)
Mode of delivery	Vaginal	83	0.023 (0.026)	0.31	87	0.029 (0.034)	0.29	88	0.026 (0.026)	0.49
	C-Section	52	0.028 (0.033)		54	0.034 (0.045)		54	0.028 (0.030)
Gestational age at birth	---	133	0.013	0.88	142	−0.023	0.79	139	0.01	0.91
Birthweight z-score	---	124	−0.208		129	−0.207	0.019	131	−0.184	0.036
Child race	White	50	0.018 (0.018)	<0.001	52	0.022 (0.025)	<0.001	52	0.020 (0.019)	<0.001
	Black	56	0.031 (0.050)		58	0.044 (0.061)		59	0.032 (0.033)
	Other/Mixed	30	0.024 (0.022)		32	0.031 (0.041)		32	0.031 (0.032)
Child sex	Male	66	0.029 (0.026)	0.072	69	0.036 (0.039)	0.065	70	0.029 (0.020)	0.33
	Female	70	0.021 (0.026)		73	0.027 (0.035)		73	0.024 (0.036)
Breastfeeding status at 1-month	Formula Feeding	25	0.032 (0.030)	0.32	26	0.042 (0.048)	0.58	26	0.028 (0.033)	0.60
	Mixed Feeding	81	0.023 (0.028)		85	0.031 (0.049)		87	0.027 (0.029)
	Exclusive Breastfeed	30	0.029 (0.025)		31	0.029 (0.023)		30	0.026 (0.031)
Breastfeeding status at 6-months	Formula Feeding	25	0.032 (0.030)	0.38	26	0.042 (0.048)	0.58	26	0.028 (0.033)	0.93
	Mixed Feeding	95	0.024 (0.027)		99	0.031 (0.042)		100	0.027 (0.026)
	Exclusive Breastfeed	16	0.024 (0.023)		17	0.026 (0.029)		17	0.025 (0.033)

^atooth lead levels shown as metal-to-calcium ratios.

^bKruskal-Wallis or Spearman correlation p-value.