| Characteristic | Total no. of pregnancies | No. (%) of screened pregnancies* | p value† | |||||
|---|---|---|---|---|---|---|---|---|
| Total screened | First trimester | Second trimester | ||||||
| Total | 264 737 | 164 783 | (62.2) | 132 355 | (50.0) | 32 428 | (12.2) | |
| Maternal age at delivery/abortion, yr | ||||||||
| ≤ 20 | 19 622 | 7 894 | (40.2) | 4 986 | (25.4) | 2 908 | (14.8) | < 0.001 |
| 21–34 | 197 976 | 122 489 | (61.9) | 98 308 | (49.7) | 24 181 | (12.2) | |
| ≥ 35 | 47 139 | 34 400 | (73.0) | 29 061 | (61.6) | 5 339 | (11.3) | |
| Maternal age at first delivery, yr | ||||||||
| ≤ 20 | 38 411 | 16 096 | (41.9) | 10 786 | (28.1) | 5 310 | (13.8) | < 0.001 |
| 21–34 | 197 873 | 126 701 | (64.0) | 102 750 | (51.9) | 23 951 | (12.1) | |
| ≥ 35 | 28 453 | 21 986 | (77.3) | 18 819 | (66.1) | 3 167 | (11.1) | |
| Parity (previous deliveries) | ||||||||
| 0 | 134 061 | 86 098 | (64.2) | 69 353 | (51.7) | 16 745 | (12.5) | < 0.001 |
| 1 | 87 628 | 56 134 | (64.1) | 45 820 | (52.3) | 10 314 | (11.8) | |
| 2 | 30 525 | 17 215 | (56.4) | 13 396 | (43.9) | 3 819 | (12.5) | |
| ≥□3 | 12 523 | 5 336 | (42.6) | 3 786 | (30.2) | 1 550 | (12.4) | |
| Previous delivery of stillborn child | 2 163 | 1 436 | (66.4) | 1 160 | (53.6) | 276 | (12.8) | 0.7 |
| Previous abortion in past 5 yr | 39 047 | 24 504 | (62.8) | 19 726 | (50.5) | 4 778 | (12.2) | 0.4 |
| Previous delivery of child with congenital anomaly | 9 229 | 5 284 | (57.3) | 4 124 | (44.7) | 1 160 | (12.6) | < 0.001 |
| Immigration status | ||||||||
| Canadian resident | 193 187 | 111 734 | (57.8) | 92 244 | (47.7) | 19 490 | (10.1) | < 0.001 |
| Immigrant | ||||||||
| Landed ≥□5 yr ago | 31 308 | 23 994 | (76.6) | 18 691 | (59.7) | 5 303 | (16.9) | |
| Landed < 5 yr ago | 31 274 | 22 977 | (73.5) | 17 082 | (54.6) | 5 895 | (18.8) | |
| Refugee | ||||||||
| Landed ≥ 5 yr ago | 5 423 | 3 679 | (67.8) | 2 758 | (50.9) | 921 | (17.0) | |
| Landed < 5 yr ago | 3 545 | 2 399 | (67.7) | 1 580 | (44.6) | 819 | (23.1) | |
| Neighbourhood income quintile | ||||||||
| 1 (lowest) | 60 660 | 35 653 | (58.8) | 25 629 | (42.3) | 10 024 | (16.5) | < 0.001 |
| 2 | 53 750 | 32 980 | (61.4) | 25 485 | (47.4) | 7 495 | (13.9) | |
| 3 | 53 273 | 33 367 | (62.6) | 27 270 | (51.2) | 6 097 | (11.4) | |
| 4 | 53 604 | 34 722 | (64.8) | 29 687 | (55.4) | 5 035 | (9.4) | |
| 5 (highest) | 41 928 | 27 474 | (65.5) | 23 912 | (57.0) | 3 562 | (8.5) | |
| Missing data | 1 522 | 587 | (38.6) | 372 | (24.4) | 215 | (14.1) | |
| Rurality index score‡ | ||||||||
| 0–9 (major urban) | 199 919 | 136 297 | (68.2) | 111 869 | (56.0) | 24 428 | (12.2) | < 0.001 |
| 10–39 (non-major urban) | 45 320 | 21 222 | (46.8) | 15 921 | (35.1) | 5 301 | (11.7) | |
| ≥ 40 (rural) | 16 697 | 6 457 | (38.7) | 4 158 | (24.9) | 2 299 | (13.8) | |
| Missing data | 2 801 | 807 | (28.8) | 407 | (14.5) | 400 | (14.3) | |
| First-trimester care provider | ||||||||
| Prenatal obstetrician | 84 553 | 64 726 | (76.6) | 55 790 | (66.0) | 8 936 | (10.6) | < 0.001 |
| Prenatal GP/FP | 118 520 | 76 385 | (64.5) | 63 251 | (53.4) | 13 134 | (11.1) | |
| Primary GP/FP | 36 684 | 18 415 | (50.2) | 10 460 | (28.5) | 7 955 | (21.7) | |
| Other physician | 7 707 | 2 997 | (38.9) | 2 063 | (26.8) | 934 | (12.1) | |
| Midwife only | 2 562 | 684 | (26.7) | 572 | (22.3) | 112 | (4.4) | |
| No care | 14 711 | 1 576 | (10.7) | 219 | (1.5) | 1 357 | (9.2) | |
Note: GP/FP = general practitioner/family physician. *Percentages are based on row totals (total no. of pregnancies). †χ2 test, for comparison of the timing of screening (first v. second trimester) among women whose pregnancy was screened. ‡Measured with the Rurality Index for Ontario. (41)