Table 1.
Demographic and baseline characteristics of BiOC and standard care before and after propensity score matching.
| Before matching |
After matching |
|||||
|---|---|---|---|---|---|---|
| Standard care (n = 563) |
BiOC (n = 461) |
Bias (%) |
Standard care (n = 345) |
BiOC (n = 345) |
Bias (%) |
|
| Age (Mean ± SD) | 27·3 ± 6·3 | 26·0 ± 6·2 | − 19·5 | 26·1 ± 6·2 | 26·0 ± 6·3 | 2·2 |
| BMI (Median, IQR) | 24·5 (20·8–30·9) | 24·4 (20·8–29·8) | − 8·6 | 24·4 (20·5–30·5) | 25·2 (20·8–30·5) | 3·7 |
| Indigenous mum | 375 (63·3%) | 432 (90·6%) | 71·7 | 296 (87·3%) | 294 (86·7%) | − 0·7 |
| Socioeconomic status (SEIFA) | ||||||
| Quintile 1 (most disadvantaged) | 109 (19·4%) | 119 (25·8%) | 15·5 | 77 (22·3%) | 74 (21·5%) | − 2·1 |
| Quintile 2 | 86 (15·3%) | 52 (11·3%) | − 11·8 | 43 (12·5%) | 46 (13·3%) | 2·6 |
| Quintile 3 | 86 (15·3%) | 82 (17·8%) | 6·8 | 57 (16·5%) | 54 (15·7%) | − 2·3 |
| Quintile 4 | 159 (28·4%) | 133 (28·9%) | 1·3 | 104 (30·1%) | 101 (29·3%) | − 1·9 |
| Quintile 5 (most advantaged) | 123 (21·9%) | 75 (16·3%) | − 14·2 | 64 (18·6%) | 70 (20·3%) | 4·4 |
| Education | ||||||
| < Grade 10 | 53 (9·4%) | 38 (8·2%) | − 4·1 | 31 (9·0%) | 38 (11·0%) | 7·1 |
| Grade 10–12 | 374 (66·4%) | 334 (72·5%) | 13·1 | 248 (71·9%) | 243 (70·4%) | − 3·1 |
| Tertiary | 136 (24·2%) | 89 (19·3%) | − 11·8 | 66 (19·1%) | 64 (18·6%) | − 1·4 |
| Marriage status | ||||||
| Married or de facto | 300 (53·3%) | 180 (39·1%) | − 28·8 | 150 (43·5%) | 158 (45·8%) | 4·7 |
| Not married or de facto | 255 (45·3%) | 273 (59·2%) | 28·1 | 189 (54·8%) | 179 (51·9%) | − 5·9 |
| Not stated | 8 (1·4%) | 8 (1·7%) | 2·5 | 6 (1·7%) | 8 (2·3%) | 4·6 |
| Parity (Median, IQR) | 1(0–2) | 1(0–2) | − 5·1 | 1(0–2) | 1(0–2) | 5·7 |
| Smoking at booking | 190 (33·8%) | 161 (34·9%) | 2·5 | 128 (37·1%) | 138 (40·0%) | 6·1 |
| Previous caesarean sections | 103 (18·3%) | 68 (14·8%) | − 9·5 | 53 (15·4%) | 61 (17·7%) | 6·2 |
| Previous stillbirths | 15 (2·7%) | 10 (2·2%) | − 3·2 | 9 (2·6%) | 10 (2·9%) | 1·9 |
| Previous preterm births | 11 (2·0%) | 8 (1·7%) | − 1·6 | 6 (1·7%) | 7 (2·0%) | 2·2 |
| Maternal comorbidities | ||||||
| Diabetes disease | 31 (5·5%) | 23 (5·0%) | − 2·3 | 19 (5·5%) | 19 (5·5%) | 0·0 |
| Liver disease | 15 (2·7%) | 14 (3·0%) | 2·2 | 9 (2·6%) | 12 (3·5%) | 5·2 |
| Heart disease | 35 (6·2%) | 31 (6·7%) | 2·1 | 25 (7·3%) | 24 (7·0%) | − 1·2 |
| Renal disease | 62 (11·0%) | 61 (13·2%) | 6·8 | 36 (10·4%) | 36 (10·4%) | 0·0 |
| Thyroid disease | 24 (4·3%) | 10 (2·2%) | − 11·9 | 8 (2·3%) | 10 (2·9%) | 3·3 |
| Haematological disease | 141 (25·0%) | 158 (34·3%) | 20·3 | 105 (30·4%) | 100 (29·0%) | − 3·2 |
| Essential hypertension | 37 (6·6%) | 17 (3·7%) | − 13·1 | 18 (5·2%) | 17 (4·9%) | − 1·3 |
| Current pregnancy complications | ||||||
| Gestational diabetes | 46 (8·2%) | 37 (8·0%) | − 0·5 | 29 (8·4%) | 28 (8·1%) | − 1·1 |
| Pregnancy induced hypertension, mild, moderate or severe preeclampsia | 12 (2·1%) | 15 (3·3%) | 6·9 | 10 (2·9%) | 6 (1·7%) | − 7·2 |
| Antepartum Haemorrhage (APH) | 12 (2·1%) | 15 (3·3%) | 6·9 | 10 (2·9%) | 6 (1·7%) | − 7·2 |
Note: BiOC = Birthing in Our Community.
Rubin's B: 84·9% before matching and 21·3% after matching.
Rubin's R: 0·5 before matching and 0·9 after matching.