Table 3.
Use of prenatal ultrasonography during the second and third trimesters among women with a singleton pregnancy in Ontario, 1996 to 2006
| All participants, by quartile | Fiscal year |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1996, n = 131 746 | 1997, n = 128 976 | 1998, n = 126 841 | 1999, n = 126 078 | 2000, n = 122 019 | 2001, n = 126 062 | 2002, n = 123 502 | 2003, n = 127 086 | 2004, n = 127 610 | 2005, n = 128 721 | 2006, n = 130 748 | |
| All participants | |||||||||||
| Q1 (0 or 1 US examinations) | |||||||||||
| No. (%) | 71 645 (54.4) | 65 522 (50.8) | 66 709 (52.6) | 62 518 (49.6) | 55 868 (45.8) | 53 793 (42.7) | 49 590 (40.2) | 47 620 (37.5) | 44 998 (35.3) | 42 234 (32.8) | 39 448 (30.2) |
| Adjusted RR (95% CI)* | 1.00 (ref) | 0.94 (0.93–0.95) | 0.97 (0.96–0.98) | 0.92 (0.91–0.93) | 0.85 (0.84–0.86) | 0.79 (0.79–0.80) | 0.75 (0.74–0.76) | 0.70 (0.69–0.71) | 0.66 (0.65–0.67) | 0.62 (0.61–0.62) | 0.57 (0.56–0.57) |
| Q2 (2 US examinations) | |||||||||||
| No. (%) | 38 100 (28.9) | 39 194 (30.4) | 37 250 (29.4) | 37 816 (30.0) | 38 429 (31.5) | 40 509 (32.1) | 40 103 (32.5) | 41 367 (32.6) | 41 239 (32.3) | 41 908 (32.6) | 42 590 (32.6) |
| Adjusted RR (95% CI)* | 1.00 (ref) | 1.05 (1.04–1.07) | 1.02 (1.00–1.03) | 1.04 (1.03–1.06) | 1.09 (1.08–1.11) | 1.12 (1.10–1.13) | 1.13 (1.11–1.14) | 1.13 (1.11–1.14) | 1.12 (1.11–1.14) | 1.13 (1.12–1.15) | 1.13 (1.12–1.15) |
| Q3 (3 US examinations) | |||||||||||
| No. (%) | 13 516 (10.3) | 14 538 (11.3) | 13 721 (10.8) | 15 029 (11.9) | 16 094 (13.2) | 17 959 (14.2) | 18 809 (15.2) | 20 714 (16.3) | 21 542 (16.9) | 22 981 (17.9) | 24 204 (18.5) |
| Adjusted RR (95% CI)* | 1.00 (ref) | 1.10 (1.07–1.12) | 1.05 (1.03–1.08) | 1.16 (1.13–1.19) | 1.28 (1.25–1.31) | 1.38 (1.34–1.41) | 1.47 (1.44–1.50) | 1.57 (1.53–1.60) | 1.62 (1.58–1.65) | 1.71 (1.67–1.75) | 1.77 (1.74–1.81) |
| Q4 (≥ 4 US examinations) | |||||||||||
| No. (%) | 8 485 (6.4) | 9 722 (7.5) | 9 161 (7.2) | 10 715 (8.5) | 11 628 (9.5) | 13 801 (10.9) | 15 000 (12.1) | 17 385 (13.7) | 19 831 (15.5) | 21 598 (16.8) | 24 506 (18.7) |
| Adjusted RR (95% CI)* | 1.00 (ref) | 1.16 (1.13–1.20) | 1.11 (1.08–1.14) | 1.29 (1.25–1.33) | 1.43 (1.39–1.47) | 1.63 (1.58–1.67) | 1.79 (1.75–1.84) | 2.00 (1.95–2.05) | 2.25 (2.19–2.31) | 2.41 (2.35–2.47) | 2.68 (2.61–2.74) |
| Low-risk subgroup | n = 111 112 | n = 108 347 | n = 106 245 | n = 105 076 | n = 100 969 | n = 103 902 | n = 101 442 | n = 104 128 | n = 103 722 | n = 104 336 | n = 105 570 |
| Q4 (≥ 4 US examinations) | |||||||||||
| No. (%) | 5 485 (4.9) | 6 486 (6.0) | 5 977 (5.6) | 7 085 (6.7) | 7 481 (7.4) | 8 884 (8.6) | 9 643 (9.5) | 11 213 (10.8) | 12 719 (12.3) | 13 845 (13.3) | 15 687 (14.9) |
| Adjusted RR (95% CI)* | 1.00 (ref) | 1.20 (1.16–1.25) | 1.13 (1.09–1.17) | 1.35 (1.30–1.39) | 1.47 (1.42–1.53) | 1.70 (1.64–1.76) | 1.89 (1.83–1.95) | 2.12 (2.05–2.19) | 2.42 (2.34–2.50) | 2.61 (2.53–2.69) | 2.92 (2.83–3.01) |
| High-risk subgroup | n = 20 634 | n = 20 629 | n = 20 596 | n = 21 002 | n = 21 050 | n = 22 160 | n = 22 060 | n = 22 958 | n = 23 888 | n = 24 385 | n = 25 178 |
| Q4 (≥ 4 US examinations) | |||||||||||
| No. (%) | 3 000 (14.5) | 3 236 (15.7) | 3 184 (15.5) | 3 630 (17.3) | 4 147 (19.7) | 4 917 (22.2) | 5 357 (24.3) | 6 172 (26.9) | 7 112 (29.8) | 7 753 (31.8) | 8 819 (35.0) |
| Adjusted RR (95% CI)* | 1.00 (ref) | 1.08 (1.03–1.14) | 1.07 (1.02–1.12) | 1.19 (1.13–1.24) | 1.34 (1.28–1.41) | 1.48 (1.42–1.55) | 1.61 (1.54–1.68) | 1.78 (1.70–1.86) | 1.94 (1.86–2.03) | 2.06 (1.97–2.15) | 2.25 (2.16–2.35) |
Note: CI = confidence interval, Q = quartile, RR = relative risk, US = ultrasonography examination.
*
Adjusted for maternal age, income quintile, rural place of residence, diabetes mellitus, hypertension, other maternal comorbidity, genetics consultation, amniocentesis – all in the index pregnancy – and for history of complications of pregnancy.