Table 1.
Relevant sociodemographic, medical and obstetrical risk factors in cases of uterine rupture
| Cases of uterine rupture 2012–2013 (n=90)* n, % |
Background population 2012–2013 (n=252 272) n, % |
Unadjusted RR (95% CI) | p Value | |
|---|---|---|---|---|
| Sociodemographic factors | ||||
| Maternal age ≥35 years | 17 (18.8) | 43 256 (17) | 1.11 (0.72 to 1.70) | 0.6 |
| BMI at booking ≥30 kg/m2 | 13 (19.6) | 29 453 (12) | 1.59 (0.9 to 2.59) | 0.05 |
| Ethnicity non-white † | 5 (5.5) | – | – | – |
| Neither married nor cohabiting | 3 (3.8) | 20 785 (17) | 0.22 (0.07 to 0.69) | 0.008 |
| Unemployed | 22 (24.4) | 51 296 (43) | 0.72 (0.50 to 1.02) | 0.06 |
| Smoking | 8 (8.8) | – | – | – |
| Medical factors | ||||
| Uterine anomaly (bicornuate, septate) | 6 (6.6) | – | – | – |
| Connective tissue disease‡ | 1 (1.1) | – | – | – |
| Obstetrical factors | ||||
| Parity ≥3 | 9 (10) | 18 855 (7.4) | 1.33 (0.71 to 2.48) | 0.3 |
| Nulliparity | 6 (6.6) | 110 711 (43.9) | 0.15 (0.07 to 0.32) | <0.0001 |
| Induction of labour | 24 (27.9) | 68 703 (26.7) | 1.03 (0.7 to 1.4) | 0.8 |
| Previous CS | 73 (81.1) | 27 007 (10.7) | 7.57 (6.85 to 8.37) | <0.0001 |
| Previous CS, cases <24 weeks excluded | 70 (81.3) | |||
| Trial of labour after CS | 57/70 (81.4) | 12 754/27 007 (47.2) | 1.39 (1.15 to 1.69) | <0.001 |
| Interpregnancy interval ≤12 months | 12 (16.4) | – | – | – |
| Artificial reproductive technology (IVF/ICSI) | 4 (4.4) | 9233 (3.7) | 1.21 (0.46 to 3.15) | 0.6 |
| Abnormal placentation (accreta, increta, percreta) | 1 (1.1) | – | – | – |
| Birth weight ≥4000 g | 11 (12.2) | 19 967 (7.8) | 1.67 (0.96 to 2.90) | 0.06 |
| Breech presentation | 4 (4.4) | 12 630 (4.9) | 0.93 (0.35 to 2.42) | 0.8 |
*Study data were not complete for all variables; data available on BMI (n=66), marital status (n=77), employment (n=71), smoking (n=87), ART (n=89), birth weight (n=84), interpregnancy interval (n=67).
†White ethnicity defined as European, Middle-Eastern, North-African, white South-African. Five women were of African descent defined as African, Caribbean or Afro-American ethnicity.
‡Connective tissue disease: the study included one known case of osteogenesis imperfecta type I.
ART, artificial reproductive technology; BMI, body mass index; CS, Caesarean section; CTG, cardiotocography; ICSI, intracytoplasmic sperm injection; IVF, in vitro fertilisation; RR, relative risk.