Table 2.
Stage of pregnancy at which active participants were recruited to the study (SOP, stage of pregnancy, participants recruited in the second or third trimesters had reached at least 13-weeks’ gestation)
| SOP | Denmark | Netherlands | Poland | United Kingdom | All Locations | |
|
|
n (%) | n (%) | n (%) | n (%) | n (%) | |
| First trimester | 309 (48.4%) | 48 (10.1%) | 48 (19.9%) | 70 (9.9%) | 475 (23.0%)a | |
|
|
≤4/40 | 58 (9.1%) | 2 (0.4%) | 3 (1.2%) | 0 (0.0%) | 63 (3.1%) |
|
|
5/40 | 53 (8.3%) | 0 (0.0%) | 4 (1.7%) | 4 (0.6%) | 61 (3.0%) |
|
|
6/40 | 53 (8.3%) | 2 (0.4%) | 5 (2.1%) | 4 (0.6%) | 64 (3.1%) |
|
|
7/40 | 37 (5.8%) | 2 (0.4%) | 5 (2.1%) | 2 (0.3%) | 46 (2.2%) |
|
|
8/40 | 29 (4.5%) | 4 (0.8%) | 8 (3.3%) | 7 (1.0%) | 48 (2.3%) |
|
|
9/40 | 23 (3.6%) | 15 (3.2%) | 0 (0.0%) | 14 (2.0%) | 52 (2.5%) |
|
|
10/40 | 21 (3.3%) | 9 (1.9%) | 4 (1.7%) | 8 (1.1%) | 42 (2.0%) |
|
|
11/40 | 20 (3.1%) | 6 (1.3%) | 9 (3.7%) | 15 (2.1%) | 50 (2.4%) |
|
|
12/40 | 15 (2.4%) | 8 (1.7%) | 10 (4.2%) | 16 (2.3%) | 49 (2.4%) |
| Second/third trimester | 330 (51.6%) | 428 (89.9%) | 193 (80.1%) | 639 (90.1%) | 1590 (77.0%) | |
| Total | 639 (100.0%) | 476 (100.0%) | 241 (100.0%) | 709 (100.0%) | 2065 (100.0%) | |
aPoisson regression (P<.001) identifies a significant difference between the four study locations in the proportion of first trimester participants recruited driven by the high proportion of Danish participants recruited in the first trimester.