Table 1.

Demographic characteristics of the study participants

	Maternal smoking status
	Nonsmoker (n = 19)	Smoker (n = 34)
	Mean ± SD	Mean ± SD	p value (Welch’s t test)
Maternal age (years)	27.1 ± 4.9	27.4 ± 4.4	0.82
Gestational age (days)	275.6 ± 7.6	272.0 ± 10.6	0.16
Birthweight (g)	3382.1 ± 262.4	3130.6 ± 423.1	0.01
Cotinine (ng/mL)	2.0 ± 0.0	86.8 ± 85.1	2.43E−06
Cigarettes per day	–	7.9 ± 5.1	–
Years smoked	–	10.9 ± 6.6	–
	Percentage	Percentage	p value (two-tail Fisher’s exact test)
Infant sex female	52.6	55.9	0.99
African-American	52.6	53.1	0.99
C section	47.4	64.7	0.38
Progesterone use during pregnancy	5.3	2.9	0.99
Any environmental tobacco smoke (ETS) exposure	10.5	85.3	5.46E−08