Table 2. Univariate comparison of demographic and pregnancy characteristics for women who had second pregnancies.
| Second pregnancy characteristic | Initial 3rd or 4th degree tear n (%) (N = 3333) |
No prior 3rd or 4th degree tear n (%) (N = 118681) |
P-value |
|---|---|---|---|
| Third/fourth degree tear Yes | 149 (4.5) | 1225 (1.0) | |
| No | 3184 (95.5) | 117456 (99.0) | <0.01* |
| Age | |||
| Missing = 1 | |||
| Mean (SD) | 30.5 (5.2) | 29.0 (5.5) | <0.01* |
| Smoking | |||
| Missing = 6584 (5.4%) | |||
| Non smoker | 2480 (78.1) | 76880 (68.5) | |
| Smoker | 380 (12.0) | 24113 (21.5) | <0.01* |
| Ex-smoker | 317 (10.0) | 11260 (10.0) | 0.014 |
| Deprivation | |||
| Missing = 302 (0.2) | |||
| Most deprived (1–5) | 1648 (49.6) | 64917 (54.8) | <0.01* |
| Least deprived (6–10) | 1675 (50.4) | 53472 (45.2) | |
| Diabetes | |||
| Missing = 19873 (16.3%) | |||
| Yes | 36 (1.2) | 1261 (1.3) | 0.684 |
| No | 2994 (98.8) | 97850 (98.7) | |
| BMI | |||
| Missing = 44646 (36.6%) | |||
| Mean (SD) | 25.9 (5.2) | 26.0 (5.4) | 0.039 |
| Mode of delivery | |||
| Missing = 24 (0.0%) | |||
| SVD | 2134 (64.1) | 103019 (86.8) | |
| Forceps (non rot) | 61 (1.8) | 2453 (2.1) | 0.165 |
| Ventouse (all) | 33 (1.0) | 1660 (1.4) | 0.956 |
| Forceps (rotational) | 15 (0.4) | 559 (0.5) | 0.195 |
| Breech vaginal | 11 (0.3) | 398 (0.3) | 0.927 |
| Elective CS | 887 (26.6) | 4416 (3.7) | <0.01* |
| Emergency CS | 190 (5.7) | 6154 (5.2) | <0.01* |
| Weight of baby (grams) | |||
| Missing = 87 (0.1%) | |||
| <4500g | 3233 (97.1) | 115520 (97.4) | 0.213 |
| ≥4500g | 98 (2.9) | 3076 (2.6) | |
| Gestation at birth (weeks) | |||
| Missing = 119 (0.1) | |||
| Mean (SD) | |||
| 39.4 (2.8) | 39.5 (2.5) | 0.07 | |
| Episiotomy | |||
| Missing = 1812 (1.5%) | |||
| Yes | 486 (15.0) | 8344 (7.4) | <0.01* |
| No | 2758 (85.0) | 104001 (92.6) | |
| Induction of labour | |||
| Missing = 447 (0.4) | |||
| None | 2821 (84.8) | 90722 (76.7) | |
| ARM only | 101 (3.0) | 5524 (4.7) | <0.01* |
| ARM + pharmacological | 406 (12.2) | 21993 (18.6) | <0.01* |
| Position at delivery | |||
| Missing = 7228 (5.9) | |||
| OA | 2690 (88.4) | 101144 (90.5) | |
| OP | 102 (3.4) | 3472 (3.1) | 0.331 |
| OT | 118 (3.9) | 3069 (2.7) | <0.01* |
| Other | 134 (4.4) | 4057 (3.6) | 0.016 |
Missing data not included in the proportions presented.
*denotes statistical significance.