Mother's age at delivery

Chance of a live-born baby with Down Syndrome *

Chance of having a live-born child with any chromosomal abnormality *

20

1 in 1923

1 in 526

21

1 in 1695

1 in 526

22

1 in 1538

1 in 500

23

1 in 1408

1 in 500

24

1 in 1299

1 in 476

25

1 in 1205

1 in 476

26

1 in 1124

1 in 476

27

1 in 1053

1 in 455

28

1 in 990

1 in 435

29

1 in 935

1 in 417

30

1 in 885

1 in 384

31

1 in 826

1 in 384

32

1 in 725

1 in 322

33

1 in 592

1 in 285

34

1 in 465

1 in 243

35

1 in 365

1 in 178

36

1 in 287

1 in 149

37

1 in 225

1 in 123

38

1 in 177

1 in 105

39

1 in 139

1 in 80

40

1 in 109

1 in 63

41

1 in 85

1 in 48

42

1 in 67

1 in 39

43

1 in 53

1 in 31

44

1 in 41

1 in 24

45

1 in 32

1 in 18

46

1 in 25

1 in 15

47

1 in 20

1 in 11

48

1 in 16

1 in 8

49

1 in 12

1 in 7