| Study Groups | No. | 1980 – 1989 | No. | 1990– 1996 | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No | Mono | Poly | Total | No | Mono | Poly | Total | |||||||||||
| No. | % | No. | % | No. | % | No. | % | No. | % | No. | % | No. | % | No. | % | |||
| Controls | 25,349 | 7 | 0.03 | 23 | 0.09 | 22 | 0.09 | 52 | 0.21 | 12,803 | 3 | 0.02 | 27 | 0.21 | 8 | 0.06 | 38 | 0.30 | 
| Isolated CAs | ||||||||||||||||||
| Neural-tube defects | 1,023 | 0 | 0.00 | 4 | 0.39 | 1 | 0.01 | 5 | 0.49 | 179 | 1 | 0.56 | 0 | 0.0 | 1 | 0.56 | 2 | 1.12 | 
| Cleft lip ± palate | 873 | 0 | 0.00 | 1 | 0.11 | 7 | 0.80 | 8 | 0.92 | 502 | 0 | 0.00 | 1 | 0.20 | 2 | 0.40 | 3 | 0.60 | 
| Cleft palate | 412 | 0 | 0.00 | 2 | 0.49 | 3 | 0.73 | 5 | 1.21 | 189 | 0 | 0.00 | 0 | 0.00 | 0 | 0.00 | 0 | 0.00 | 
| Cardiovascular CAs | 2,664 | 2 | 0.08 | 5 | 0.19 | 10 | 0.38 | 17 | 0.64 | 1,816 | 3 | 0.17 | 3 | 0.17 | 2 | 0.11 | 8 | 0.44 | 
| Oesophageal atresia/stenosis | 146 | 0 | 0.00 | 2 | 1.37 | 0 | 0.00 | 2 | 1.37 | 71 | 0 | 0.00 | 0 | 0.00 | 1 | 1.41 | 1 | 1.41 | 
| Hypospadias | 1,846 | 1 | 0.05 | 2 | 0.11 | 2 | 0.11 | 5 | 0.27 | 1,192 | 2 | 0.17 | 5 | 0.42 | 1 | 0.08 | 8 | 0.67 | 
| Undescended testis | 1,267 | 0 | 0.00 | 5 | 0.19 | 0 | 0.00 | 5 | 0.39 | 785 | 0 | 0.00 | 1 | 0.13 | 1 | 0.13 | 2 | 0.25 | 
| Clubfoot | 1,614 | 0 | 0.00 | 3 | 0.19 | 1 | 0.06 | 4 | 0.25 | 811 | 0 | 0.00 | 1 | 0.06 | 0 | 0.00 | 1 | 0.14 | 
| Poly/syndactyly | 1,042 | 2 | 0.19 | 0 | 0.00 | 1 | 0.10 | 3 | 0.29 | 702 | 0 | 0.00 | 1 | 0.14 | 1 | 0.14 | 2 | 0.28 | 
| Other isolated CAs | 2,770 | 1 | 0.04 | 3 | 0.11 | 3 | 0.11 | 7 | 0.25 | 1,590 | 0 | 0.00 | 1 | 0.06 | 1 | 0.06 | 2 | 0.13 | 
| Multiple CAs | 951 | 0 | 0.00 | 1 | 0.11 | 3 | 0.32 | 4 | 0.42 | 398 | 0 | 0.00 | 0 | 0.00 | 1 | 0.25 | 1 | 0.25 | 
| Total | 14,608 | 6 | 0.04 | 28 | 0.19 | 31 | 0.21 | 65 | 0.44 | 8,235 | 6 | 0.07 | 13 | 0.16 | 11 | 0.13 | 30 | 0.36 |