Plurality of birth | ART | Population-based controls N (%) | All ARM cases | Prospectively collected ARM cases in 2009 to 2011 | ||||
---|---|---|---|---|---|---|---|---|
N (%) | OR (95% CI) | P value | N (%) | OR (95% CI) | P value | |||
Singletons | No | 9,664,317 (99%) | 249 (94%) | 1.0 (Reference) | - | 116 (94%) | 1.0 (Reference) | - |
IVF | 26,743 (0.3%) | 7 (3%) | 10.2 (4.8–21.5) | <0.0001 | 3 (3%) | 9.4 (3.0–29.4) | <0.0001 | |
ICSI | 54,296 (0.6%) | 9 (3%) | 6.4 (3.3–12.5) | <0.0001 | 4 (3%) | 6.1 (2.3–16.6) | <0.0001 | |
Multiple births | No | 275,687 (85%) | 16 (53%) | 1.0 (Reference) | - | 5 (42%) | 1.0 (Reference) | - |
IVF | 18,060 (6%) | 6 (20%) | 5.7 (2.2–14.6) | <0.0001 | 3 (25%) | 9.2 (2.2–38.3) | 0.0002 | |
ICSI | 30,883 (10%) | 8 (27%) | 4.5 (1.9–10.4) | 0.0002 | 4 (33%) | 7.1 (1.9–26.6) | 0.0006 |