Table 1.

Numbers of newborns, children with Down syndrome, and prevalence rates of Down syndrome, California (1996–97) and the Czech Republic (1994–98)

	California					Czech Republic
	All children		Children with DS			All children		Children with DS
	No.	% of births	No.	% of births	Prevalence per 10 000	No.	% of births	No.	% of births	Prevalence per 10 000
Sex of infants
Boy	264 321	51.2	328	55.3	12.4	244 503	51.4	144	57.4	5.9
Girl	252 408	48.8	265	44.7	10.5	231 331	48.6	107	42.6	4.6
Unknown	16		0			0		0
Education of mother
Primary	85 615	16.6	157	26.5	18.3	64 774	13.6	34	13.5	5.2
Vocational	107 633	20.8	96	16.2	8.9	199 260	41.9	110	43.8	5.5
Secondary	234 312	45.3	251	42.3	10.7	168 659	35.4	80	31.9	4.7
University	83 681	16.2	77	13.0	9.2	43 135	9.1	27	10.8	6.3
Unknown	5 504		12			6		0
Maternal age
-19	65 058	12.6	31	5.2	4.8	46 236	9.7	17	6.8	3.7
20–22	73 102	14.1	46	7.8	6.3	118 195	24.8	57	22.7	4.8
23–25	79 444	15.4	55	9.3	6.9	121 827	25.6	50	19.9	4.1
26–28	83 791	16.2	56	9.4	6.7	85 173	17.9	40	15.9	4.7
29–31	78 435	15.2	64	10.8	8.2	52 998	11.1	28	11.2	5.3
32–34	64 442	12.5	101	17.0	15.7	28 689	6.0	27	10.8	9.4
35–37	42 301	8.2	75	12.6	17.7	14 171	3.0	14	5.6	9.9
38–40	21 289	4.1	83	14.0	39.0	6 431	1.4	7	2.8	10.9
41–43	7 173	1.4	68	11.5	94.8	1 818	0.4	6	2.4	33.0
44+	1 527	0.3	14	2.4	91.7	296	0.1	5	2.0	168.9
Unknown	183		0			0		0
Paternal age
-19	24 635	4.8	14	2.4	5.7	6 670	1.4	3	1.2	4.5
20–22	47 498	9.2	30	5.1	6.3	49 493	10.4	14	5.6	2.8
23–25	64 126	12.4	41	6.9	6.4	87 675	18.4	43	17.1	4.9
26–28	74 838	14.5	54	9.1	7.2	88 677	18.6	41	16.3	4.6
29–31	75 282	14.6	82	13.8	10.9	68 831	14.5	29	11.6	4.2
32–34	69 024	13.4	76	12.8	11.0	42 989	9.0	24	9.6	5.6
35–37	51 791	10.0	75	12.6	14.5	23 953	5.0	21	8.4	8.8
38–40	32 849	6.4	46	7.8	14.0	14 105	3.0	14	5.6	9.9
41–43	18 406	3.6	66	11.1	35.9	7 402	1.6	7	2.8	9.5
44+	18 286	3.5	66	11.1	36.1	6 610	1.4	9	3.6	13.6
Unknown	40 010		43			79 429		46
Total	516 745	100	593	100	11.5	475 834	100	251	100	5.3