N (%) | |
1) Age group (years) | |
<20 | 123 (5.8) |
20 - 29 | 1098 (51.8) |
30 - 39 | 782 (36.9) |
40+ | 117 (5.5) |
Total | 2120 (100) |
Range (14 to 50) | |
Mean ± SD (29.1 ± 6.3) | |
2) Count of US exams for each study subject | |
1 | 1253 (59.6) |
2 | 503 (23.9) |
3 | 203 (9.7) |
4 | 83 (3.9) |
5 | 37 (1.8) |
6 | 15 (0.7) |
7 | 8 (0.4) |
Total | 2102 (100) |
3) Gestational age (the earliest in case of repeated US exams) | |
Early pregnancy (<8 weeks) | 5 (0.2) |
First trimester (8 - 14 weeks) | 487 (23.2) |
Second trimester | 1096 (52.1) |
Third trimester | 514 (24.5) |
Total | 2102 (100) |
Range (6.4 - 43) | |
Mean ± SD (21.7 ± 8.2) |