Univariate analysis of maternal and infant characteristics
| p Values | ||||||
|---|---|---|---|---|---|---|
| Characteristic | Singletons (n=3717) | Twins (n=1394) | Triplets (n=483) | 1 v 2 | 1 v 3 | 2 v 3 |
| Values are either percentage or mean (SD). Maternal hypertension = pregnancy induced or chronic hypertension. | ||||||
| *p>0.05; **p<0.05; ***p<0.01; ****p<0.001. | ||||||
| Maternal/delivery | ||||||
| Week at start of prenatal care | ||||||
| 0–12 | 71.0% | 84.0% | 95.0% | **** | **** | **** |
| 13–20 | 13.1% | 9.6% | 4.4% | |||
| >20 or none | 9.4% | 4.3% | 0 | |||
| Unknown | 6.5% | 2.1% | 0.6% | |||
| Maternal age (years) | 29.3 (6.3) | 29.2 (5.5) | 29.0 (5.1) | * | * | * |
| Ethnic origin (Jewish) | 70.6% | 80.6% | 78.3% | **** | *** | * |
| Fertility treatment | 10.3% | 56.2% | 91.3% | **** | **** | **** |
| Maternal hypertension | 26.4% | 9.7% | 14.3% | **** | **** | *** |
| Antenatal steroids | ||||||
| Full | 39.7% | 46.8% | 65.6% | **** | **** | **** |
| Partial | 16.1% | 22.0% | 11.8% | |||
| None | 43.8% | 30.9% | 22% | |||
| Unknown | 0.4% | 0.3% | 0.6% | |||
| Caesarean saection | 62.1% | 64.8% | 89% | * | **** | **** |
| Neonatal | ||||||
| Birth weight (g) | 1096 (269) | 1062 (271) | 1049 (259) | ** | ** | * |
| Gestational age (weeks) | 28.9 (2.6) | 28.4 (2.3) | 28.5 (2.4) | ** | ** | * |
| Sex (male) | 53.1% | 52.2% | 50.1% | * | * | * |
| Apgar ≤3 at 5 minutes | 4.1% | 4.1% | 3.9% | * | * | * |
| Small for gestational age | 22.8% | 15.5% | 16.4% | * | *** | * |
| Resuscitation in delivery room | 82.2% | 86.1% | 83.6% | ** | * | * |