Table 1.

The contributions of the environmental factors to ASD development

Environmental factors	Odds ratio [OR]/Hazard ratios (HR)/Confidence interval [CI]	Increased risk for ASD	Reference
Obesity	OR 1.36, 95% CI 1.08-1.70	36%	[16]
Maternal diabetes	OR 1.48, 95% CI 1.26-1.75	62%	[9]
Maternal gestational diabetes mellitus	OR 1.63, 95% CI 1.35-1.97	42%	[9]
Polycystic ovary syndrome (POS)	OR 1.59, CI 95% 1.34-1.88	59%	[17,18]
Maternal antidepressant (selective serotonin reuptake inhibitors)	HR 2.17; 95% CI, 1.20-3.93	N/D	[19]
Maternal depression	HR 1.75; 95% CI, 1.03-2.97	87%	[20]
Maternal hypertension	OR 1.35, 95% CI 1.11-1.64	35%	[20]
Maternal infection	OR 1.13, 95% CI=1.03-1.23	30%	[21]
Maternal dichlorodiphenyl dichloroethylene (p,p’-DDE) exposure	OR 2.21, 95% CI 1.32-3.69	N/D	[22]
Prenatal exposure to organophosphate (dialkyl phosphates)	OR 2.0, 95% CI 1.1-3.6	60%	[23]
In vitro fertilization	OR 1.14, 95% CI 0.94-1.39	N/D	[24]

All the analyses were performed using SAS statistical software (SAS Institute Inc., Cary, NC, USA). The distribution of the characteristics of the pregnancy factors was calculated based on the autism and maternal statuses using two-tailed independent sample t-tests of continuous testing and the chi-square tests of the categorical variables. The association between maternal status and ASD was determined using a multivariate logistic regression model to evaluate the odds ratio (OR) and the 95% confidence interval (CI). N/D-Not Defined.