Table 1.

EMA demographic characteristics

	ASD (N = 78)		DD (N = 45)		GP (N = 149)		Autism versus GP p valuea	Autism versus DD p valuea
	n	%	n	%	n	%
Child’s sex							0.664b	0.001b
Male	68	87.18	27	60	133	89.26
Female	10	12.82	18	40	16	10.74
Birth year							0.248b	0.019b
2000	22	28.21	23	51.11	31	20.81
2001	56	71.79	22	48.89	118	79.19
Plurality							0.416b	1b
Singleton	75	96.15	43	95.56	146	97.99
Multiple	3	3.85	2	4.44	3	2.01
Mother’s race							0.074	0.771
White	51	67.11	33	73.33	118	79.19
Asian	19	25	9	20	27	18.12
Other	6	7.89	3	6.67	4	2.68
Mother’s ethnicity							0.001	<0.001
Non-Hispanic	60	76.92	19	42.22	80	53.69
Hispanic	18	23.08	26	57.78	69	46.31
Maternal birth Country							<0.001	<0.001
US	41	52.56	12	26.67	63	42.28
Mexico	8	10.26	22	48.89	57	38.26
Other	29	37.18	11	24.44	29	19.46
Maternal age (years) mean (SD)	30.7 (5.3)		28.5 (5.1)		28.3 (5.6)		0.0016	0.0285
Maternal age (years)							0.027	0.146
<20	2	2.56	3	6.67	8	5.37
20–24	7	8.97	6	13.33	31	20.81
25–29	18	23.08	17	37.78	44	29.53
30–34	34	43.59	14	31.11	48	32.21
35+	17	21.79	5	11.11	18	12.08
Maternal weight prior to XAFP blood draw (lbs) mean (SD)	143.6 (26.4)		147.3 (35.3)		144.6 (27.2)		0.7997	0.5186
Gestational age at XAFP blood draw (days) mean (SD)	119.9 (8.2)		118.8 (8.7)		118.8 (7.4)		0.3057	0.4962
Gestational age at birth (days) mean (SD)	271.0 (14.5)		265.2 (29.0)		271.7 (19.0)		0.753	0.1385
Gestational age at birth (weeks)							0.849	0.239
<33	2	2.56	4	9.09	4	2.68
33 to <37	7	8.97	5	11.36	17	11.41
≥37	69	88.46	35	79.55	128	85.91

^at test for means, Chi squared for frequencies (of non-missing/unknown categories), excluding missing data

^bFisher’s exact test, excluding missing data