Table 1

Demographics and obstetric characteristics

CaseControlp Value
N (%)N (%)
Total295 (100.0)570 (100.0)
Country
 Australia 227 (76.9)436 (76.5)0.88
 New Zealand68 (23.1)134 (23.5)
Maternal age
 <257 (2.4)93 (16.3)<0.001
 25–2944 (14.9)147 (25.8)
 30–3494 (31.9) 177 (31.1)
 35–39112 (38.0)121 (21.2)
 ≥4038 (12.9)32 (5.6)
Indigenous status (Australian only)
 Yes11 (4.8)13 (3.0)0.21
 No202 (89.0)403 (92.4)
 Not stated14 (6.2)20 (4.6)
Ethnicity (New Zealand only)
 Maori13 (19.1)18 (13.4)0.34
 New Zealand European34 (50.0) 63 (47.0)
 Pacific peoples5 (7.4)17 (12.7)
 Other12 (17.6)34 (25.4)
 Not stated4 (5.9)2 (1.5)
Body mass index (kg/m2)
 <25115 (39.0) 272 (47.7)<0.05
 25–29.966 (22.4)128 (22.5)
 ≥3078 (26.4)112 (19.6)
 Not stated36 (12.2)58 (10.2)
Smoking during pregnancy
 Yes56 (19.0)97 (17.0)0.45
 No215 (72.9)429 (75.3)
 Not stated24 (8.1)44 (7.7)
Parity
 046 (15.6)240 (42.1)<0.001
 1–2159 (53.9)274 (48.1)
 ≥390 (30.5)56 (9.8)
Number of previous caesarean deliveries
 No prior caesarean delivery43 (14.6)225 (39.5)<0.001
 189 (30.2)80 (14.0)
 262 (21.0)19 (3.3)
 ≥350 (16.9)3 (0.5)
 Not applicable (no prior births)46 (15.6)240 (42.1)
 Not stated5 (1.7)3 (0.5)
Last pregnancy delivery by caesarean delivery
 Yes188 (63.7)91 (16.0)<0.001
 No55 (18.6)234 (41.1)
 Not applicable (no prior births)46 (15.6)240 (42.1)
 Not stated6 (2.0)5 (0.9)
Placenta praevia during pregnancy
 Yes130 (44.1)8 (1.4)<0.001
 No165 (55.9)562 (98.6)
Multiple pregnancy
 Yes15 (5.1)13 (2.3)<0.05
 No280 (94.9)555 (97.4)
 Not stated0 (0.0)2 (0.4)
Assisted conception
 Yes24 (8.1)15 (2.6)<0.001
 No259 (87.8)521 (91.4)
 Not stated12 (4.1)34 (6.0)