Table 2.
Abnormalities according to multiplicity
| Abnormalities | Singleton births | Multiple births | All births | Unudjusted | Adjusted | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Spontaneous conception | Non spontaneous conception | Spontaneous conception | Non spontaneous conception | Spontaneous conception | Non spontaneous conception | |||||||||
| N | % | N | % | N | % | N | % | N | % | N | % | OR (95%CI) | OR (95%CI) | |
| Any defect (any code) | 11,440 | 4.3 | 264 | 5.6 | 524 | 8.3 | 208 | 8.9 | 11,964 | 4.4 | 472 | 6.7 | 1.67 (1.5–1.9) | 0.95 (0.8–1.1)* |
| Multiple defects | 1487 | 0.6 | 35 | 0.7 | 60 | 1.0 | 27 | 1.2 | 1547 | 0.6 | 62 | 0.9 | 1.76 (1.3–2.3) | 1.05 (0.8–1.4)* |
| Central nervous system (codes 740*–742*) | 500 | 0.2 | 9 | 0.2 | 23 | 0.4 | 8 | 0.3 | 523 | 0.2 | 17 | 0.2 | 1.30 (0.7–2.3) | 0.78 (0.4–1.4)* |
| Eye (codes 743*) | 57 | 0.0 | 3 | 0.1 | 1 | 0.0 | – | – | 58 | 0.0 | 3 | 0.0 | – | – |
| Ear, face and neck (codes 744*) | 258 | 0.1 | 6 | 0.1 | 1 | 0.0 | 2 | 0.1 | 259 | 0.1 | 8 | 0.1 | – | – |
| Cardiovascular (codes 745*–747*) | 4439 | 1.7 | 100 | 2.1 | 326 | 5.2 | 123 | 5.3 | 4765 | 1.8 | 223 | 3.2 | 2.05 (1.8–2.4) | 0.87 (0.7–1.04)** |
| Respiratory (codes 748*) | 140 | 0.1 | 3 | 0.1 | 10 | 0.2 | – | – | 150 | 0.1 | 3 | 0.0 | – | – |
| Grastrointestinal (codes 749*–751*) | 960 | 0.4 | 24 | 0.5 | 24 | 0.4 | 11 | 0.5 | 984 | 0.4 | 35 | 0.5 | 1.38 (0.9–2.1) | 1.11 (0.7–1.7)** |
| Urogenital (codes 752*–753*) | 2020 | 0.8 | 46 | 1.0 | 61 | 1.0 | 20 | 0.9 | 2081 | 0.8 | 66 | 0.9 | 1.08 (0.8–1.5) | 0.91 (0.7–1.3)** |
| Muscoloskeletal (codes 754*–756*) | 2730 | 1.0 | 83 | 1.8 | 87 | 1.4 | 47 | 2.0 | 2817 | 1.0 | 130 | 1.8 | 2.05 (1.7–2.5) | 1.31 (1.1–1.6)**¥ |
| Tegument 757* | 276 | 0.1 | – | – | 5 | 0.1 | 1 | 0.0 | 281 | 0.1 | 1 | 0.0 | – | – |
| Chromosomal (codes 758*) | 382 | 0.1 | 6 | 0.1 | 5 | 0.1 | 2 | 0.1 | 387 | 0.1 | 8 | 0.1 | – | – |
| Other non specified (codes 759*) | 285 | 0.1 | 5 | 0.1 | 1 | 0.0 | 3 | 0.1 | 286 | 0.1 | 8 | 0.1 | – | – |
| Metabolic (codes 24390–27790) | 312 | 0.1 | 7 | 0.1 | 12 | 0.2 | 8 | 0.3 | 324 | 0.1 | 15 | 0.2 | 1.97 (1.1–3.5) | 1.11 (0.6–2.1)** |
| Hematologic (codes 282*-286*) | 127 | 0.0 | 2 | 0.0 | 10 | 0.2 | – | – | 137 | 0.1 | 2 | 0.0 | – | – |
Any defect (singleton births); OR = 1.39, 95%CI = 1.2–1.6
Any defect (multiple births); OR = 1.18, 95%CI = 0.98–1.4
OR Odds ratio; CI Confidence interval
*Adjusted for maternal age, citizenship, maternal and paternal education, parity, fetal sex, course of pregnancy, gestational age, birth-weight, single or multiple delivery (the last one just for the model including all births)
**Adjusted for maternal age, citizenship, parity, fetal sex, course of pregnancy, gestational age, birth-weight, single or multiple delivery (the last one just for the model including all births). The model was calculated excluding cases with missing gestational age
All models were calculated excluding cases with missing categories
¥Not significant if adjusted for multiple testing