Table 1.

Descriptive Statistics By Exposure Group and Relative Influence in Propensity Scores

Confounding variables	Tobacco exposed		Nonexposed		Ranka	%
	M/%	SD	M/%	SD
Maternal age at delivery (years)**	25.2	4.9	26.6	4.9	4	7.65
Maternal education (years)***	12.98	1.56	13.88	1.71	2	9.83
% Medicaid	85	—	84	—	31	0.26
% Married***	37	—	57	—	32	0.25
Maternal race (% White)	77	—	77	—	28	0.34
Maternal weight
Prepregnancy	162.2	48.2	167.2	45.8	9	3.61
Delivery	197.7	47.9	196.6	45.4	16	2.05
Gain**	35.5	19.6	29.4	14.9	8	4.38
Number of previous pregnancies	1.68	2.05	1.61	1.55	20	1.44
Healthy diet	4.38	0.69	4.51	0.76	13	2.52
Exercise (% three times per week)
Prepregnancy	47	—	53	—	26	0.54
16 weeks	39	—	48	—	21	1.33
28 weeks	42	—	42	—	35	0.11
Delivery	31	—	34	—	34	0.17
% Prenatal marijuana use***	20	—	5	—	7	4.45
Average number of alcohol drinks per day+
At last menstrual period***	0.467	0.926	0.109	0.337	3	8.55
Month 1 pregnancy***	0.245	0.398	0.036	0.092	1	14.88
Month 2 pregnancy**	0.032	0.114	0.005	0.034	23	1.22
Month 3 pregnancy	0.006	0.037	0.002	0.008	33	0.23
Month 4 pregnancy	0.003	0.010	0.001	0.007	39	0.03
Month 5 pregnancy	0.003	0.012	0.001	0.006	29	0.32
Month 6 pregnancy*	0.004	0.016	0.001	0.006	30	0.30
Month 7 pregnancy*	0.005	0.018	0.001	0.005	40	0.03
Month 8 pregnancy	0.005	0.027	0.001	0.010	38	0.05
Month 9 pregnancy	0.005	0.028	0.001	0.007	41	0.02
% Prenatal prescription medication
Antidepressants	12	—	8	—	36	0.10
Opioid-based analgesics	22	—	19	—	27	0.47
Asthma	5	—	7	—	37	0.06
Thyroid**	2	—	4	—	—	0.00
BIA maternal IQ score***	95.08	11.52	99.51	12.20	5	6.43
BSI subscale T score
Anxiety*	50.70	9.61	48.59	9.21	19	1.54
Depression**	53.70	8.74	51.21	9.00	17	1.94
Hostility	57.49	9.16	56.33	8.54	18	1.88
Interpersonal sensitivity	53.28	9.12	52.95	9.16	15	2.08
Obsessive–compulsive	56.91	10.73	56.83	10.18	22	1.31
Paranoid ideation	52.59	9.13	51.24	8.81	25	0.88
Phobic anxiety**	51.62	8.52	49.35	7.24	11	3.10
Psychoticism**	55.40	9.49	52.67	8.73	24	0.98
Somatization	58.95	8.70	58.23	8.46	14	2.47
CAARS subscale T score
Hyperactivity	47.98	8.32	46.46	7.33	6	5.81
Impulsivity	46.16	6.92	45.66	6.94	12	2.78
Inattention	48.03	8.40	47.83	7.99	10	3.60

Note. BIA = Woodcock-Johnson III Brief Intellectual Ability; BSI = Brief Symptom Inventory; CAARS = Connors Adult ADHD Rating Scale-Short Form.

^aRank based on the magnitude of the relative influence listed in the last column; rank is not given if the relative influence is 0%.

*p < .05; **p < .01; ***p < .001.