Table 1.

Comparison of this study’s sub-sample to the metals-sample across important maternal and infant characteristics.

Maternal and Infant Characteristics	Expression Sub-Sample (n=94)		Metals-Sample (n=242)		Cross-Sample Comparisons
	N	%	N	%	χ2 p-value
Mother Didn’t Smoke	87	95.60	218	92.37	0.46
Smoked During Pregnancy*	4	4.40	18	7.63
Female infant	53	56.38	119	49.17	0.29
Male infant	41	43.62	123	50.83
SGA	18	19.15	39	16.12	0.56
AGA	48	51.06	139	57.44
LGA	28	29.79	64	26.45
	Mean	Std. Dev.	Mean	Std. Dev.	T-test p-value
BW percentiles	55.3	35.07	57.61	33.02	0.58
BW (g)	3523.55	683.67	3558.95	648.41	0.67
Maternal BMI	26.48	6.72	26.72	6.52	0.77
Maternal Age	31.68	4.07	31.70	4.40	0.97
Gestational time (weeks)	39.02	0.84	39.04	0.94	0.88
Maternal Cadmium (μg/g)**	0.01	0.02	0.01	0.01	0.86

BW = birthweight; BMI = body mass index; SGA = small for gestational age; AGA = adequate for gestational age; LGA = large for gestational age.

^*Fisher’s Exact Test used to compare across samples due to low frequencies.

^**Wilcox Rank-Sum Test used to compare across samples due to skewed distribution.