Table 3. Quadratic regression model with all explanatory variables for pre- and postnatal cases with trisomy 21.

	Estimate	Estimated OR (exp(estimate))	95% Confidence interval	P-value
Intercept	−3.7392	0.02	0.00–0.12	0.00001
Mother	−0.1694	0.84	0.77–0.93	0.00085
Mother 2	0.0053	1.005	1.004–1.007	<10−5
Father	−0.1985	0.82	0.76–0.89	<10−5
Father 2	0.0022	1.002	1.001–1.003	0.002