Table 1. . Summary of ELGAN study demographics for the subcohort used in this analysis (n = 386), consisting of mothers who contributed placentas analyzed for miRNA and mRNA expression profiles.

	Overall (n = 386)	Impaired neurocognition (n = 87)	Normal neurocognition (n = 299)
	N (%) or mean (SD)	N (%) or mean (SD)	N (%) or mean (SD)
Gestational age (days)	182.5 (165–195)	180.5 (165–195)	183.1 (165–195)
Maternal age category (years)
<21	44 (11.4)	13 (14.9)	31 (10.4)
21–35	260 (67.4)	60 (69.0)	200 (66.9)
>35	82 (21.2)	14 (16.1)	68 (22.7)
Infant sex
Male	203 (52.6)	56 (64.4)	147 (49.2)
Female	183 (47.4)	31 (35.6)	152 (50.8)
Race
White	235 (60.9)	38 (43.7)	197 (65.9)
Black	112 (29.0)	39 (44.8)	73 (24.4)
Other	35 (9.06)	10 (11.5)	25 (8.36)
Missing	4 (1.04)	0 (0)	4 (1.34)
Ethnicity
Non-Hispanic	354 (91.7)	79 (90.8)	275 (92.0)
Hispanic	32 (8.3)	8 (9.2)	24 (8.0)
Smoking status
Yes	41 (10.6)	9 (10.3)	32 (10.7)
No	338 (87.6)	76 (87.4)	262 (87.6)
Missing	7 (1.8)	2 (2.3)	5 (1.7)
Marital status (single)
Yes	166 (43.0)	46 (52.9)	120 (40.1)
No	220 (57)	41 (47.1)	179 (59.9)
Maternal years of education
≤12	147 (38.1)	47 (54.0)	100 (33.4)
13–15	84 (21.8)	18 (20.7)	66 (22.1)
16+	144 (37.3)	20 (23.0)	124 (41.5)
Missing	11 (2.8)	2 (2.3)	9 (3.0)
Maternal prepregnancy BMI
Underweight	29 (7.5)	7 (8.0)	19 (6.3)
Normal	199 (51.6)	37 (42.6)	162 (54.2)
Overweight	67 (17.4)	13 (14.9)	54 (18.1)
Obese	81 (21.0)	27 (31.0)	54 (18.1)
Missing	13 (3.4)	3 (3.5)	10 (3.3)
Health insurance status
Health maintenance organization or private	236 (61.1)	39 (44.8)	197 (65.9)
Self-pay	5 (1.3)	0 (0.0)	5 (1.7)
Medicaid	126 (32.6)	43 (49.4)	83 (27.8)
None	5 (1.3)	1 (1.2)	4 (1.3)
Other	6 (1.6)	3 (3.4)	3 (1.0)
Missing	8 (2.1)	1 (1.2)	7 (2.3)
Birth weight category
<750	144 (37.3)	44 (50.6)	100 (33.4)
751–1000	171 (44.3)	33 (37.9)	138 (46.2)
1001–1250	63 (16.3)	8 (9.2)	55 (18.4)
<1250	8 (2.1)	2 (2.3)	6 (2.0)

Participants with missing data were included in the percentage calculation.

SD: Standard deviation; BMI: Body mass index.