Down's Syndrome Association

Estimated likelihood of having a baby with Down's syndrome

Mother’s Age (at expected date of delivery)	Probability of baby with Down’s syndrome		Mother’s Age (at expected date of delivery)	Probability of baby with Down’s syndrome
15	1 in 1578	34	1 in 474
16	1 in 1572	35	1 in 384
17	1 in 1565	36	1 in 307
18	1 in 1556	37	1 in 242
19	1 in 1544	38	1 in 189
20	1 in 1528	39	1 in 146
21	1 in 1507	40	1 in 112
22	1 in 1481	41	1 in 85
23	1 in 1447	42	1 in 65
24	1 in 1404	43	1 in 49
25	1 in 1351	44	1 in 37
26	1 in 1286	45	1 in 28
27	1 in 1208	46	1 in 21
28	1 in 1119	47	1 in 15
29	1 in 1018	48	1 in 11
30	1 in 909	49	1 in 8
31	1 in 796	50	1 in 6
33	1 in 574

Source: St Bartholomews Hospital, London, (Wolfson Institute)