TABLE 3.

Autism risk by birthweight percentile after multivariate analysis

Variable	aOR	95% CI	95% Wald
Birthweight percentile
<5%	1.10	1.04–1.18	1.04	1.18
5–10%	1.04	0.98–1.11	0.98	1.11
>10 to <90%	1.00	Reference
90–95%	1.04	0.97–1.10	0.97	1.10
>95%	1.12	1.05–1.19	1.05	1.19
Multivariate analysis
Maternal preeclampsia	1.11	0.95–1.29	0.95	1.29
Maternal hypertension	1.09	0.95–1.25	0.95	1.25
Maternal diabetes	1.22	1.15–1.30	1.15	1.30
Maternal age
≤20	0.58	0.55–0.61	0.55	0.61
21–25	1.00	Reference
26–30	1.3 5	1.30–1.40	1.30	1.40
30–35	1.76	1.69–1.83	1.69	1.83
35–40	2.19	2.09–2.30	2.09	2.30
≥41	2.42	2.22–2.65	2.22	2.65
Twin gestation	1.56	1.41–1.73	1.41	1.73
Birth order
1	1.0	Referenee;
2	0.62	0.50–0.76	0.50	0.76
≥3	1.13	0.42–3.05	0.44	3.19
Unknown	1.18	1.14–1.23	1.14	1.23
Race
Non-hispanic white	1.00	Reference	Reference
Hispanic	0.83	0.80–0.86	0.80	0.86
African American	1.19	1.13–1.25	1.13	1.25
Asian	1.15	1. 10–1. 19	1. 10	1. 19
Other	0.72	0.63–0.83	0.63	0.83
Time since last live birth
Missing	1.74	1.67–1.82	1.67	1.82
0–1 5 y	1.89	1.78–2.02	1.78	2.02
1.5–2.5 y	1.60	1.52–1.69	1.52	1.69
2.5–4 y	1.00	Reference	Reference
4–6 y	0.81	0.75–0.86	0.75	0.86
≥6 y	0.99	0.94–1.06	0 94	1.06

aOR, adjusted odds ratio; CI, confidence interval.

Moore. Autism risk by birthweight percentile. Am J Obstet Gynecol 2012.