Table E

Crude and adjusted odd ratio (OR) and 95% confidence interval from multivariable logistic regression of autistic spectrum disorder (ASD) for month of conception, by socioeconomic status (SES)

Month of conception	SES 1-6						SES 7-10
Month of conception	OR crude	95%CI		OR adjusted*	95%CI		OR crude	95%CI		OR adjusted*	95%CI
January	1 (ref.)			1 (ref.)			1 (ref.)			1 (ref.)
February	0.89	0.52	1.50	0.89	0.52	1.51	1.09	0.72	1.65	1.08	0.72	1.63
March	1.13	0.70	1.85	1.14	0.70	1.86	0.84	0.55	1.30	0.84	0.54	1.29
April	0.90	0.53	1.53	0.89	0.53	1.52	1.06	0.71	1.60	1.09	0.72	1.64
May	1.05	0.63	1.75	1.03	0.62	1.71	0.94	0.62	1.44	0.95	0.62	1.45
June	1.19	0.72	1.96	1.17	0.71	1.93	0.74	0.46	1.16	0.75	0.47	1.18
July	0.79	0.45	1.38	0.79	0.45	1.38	0.96	0.63	1.45	0.97	0.64	1.47
August	1.11	0.67	1.83	1.09	0.66	1.81	1.13	0.76	1.68	1.13	0.76	1.68
September	1.29	0.79	2.10	1.28	0.78	2.08	1.09	0.73	1.64	1.10	0.73	1.65
October	0.95	0.57	1.58	0.96	0.58	1.59	0.88	0.58	1.34	0.89	0.58	1.35
November	1.14	0.70	1.86	1.14	0.70	1.86	1.16	0.78	1.72	1.16	0.78	1.72
December	1.18	0.74	1.91	1.18	0.74	1.91	0.90	0.59	1.36	0.89	0.59	1.36

*Adjusted for child’s age, father’s age, mother’s age, district, birth weight, age with imputation.see text for details