Table 4.
Multilevel logistic regression: rate of referrals in a practice and the chance of instrumental birth
| 4a. Nulliparous women | 4b.Multiparous women | ||||||
|---|---|---|---|---|---|---|---|
| Rate of intrapartum nulliparous referrals in midwifery practice (tertiles) | Rate of intrapartum nulliparous referrals in midwifery practice (tertiles) | ||||||
| T1 (low) | T2 | T3 (high) | T1 (low) | T2 | T3 (high) | ||
| Instrumental birth rate | 22.7% | 26.5% | 28.0 | Instrumental birth rate | 2.7% | 2.8% | 2.8% |
| Crude OR (95% CI) | 1 | 1.23 (1.16 - 1.31) | 1.33 (1.25 - 1.41) | Crude OR (95% CI) | 1 | 1.06 (0.96 - 1.18) | 1.05 (0.95 - 1.17) |
| Model 1 adjusted OR (95% CI) | 1 | 1.22 (1.15 - 1.30) | 1.33 (1.25 - 1.41) | Model 1 adjusted OR (95% CI) | 1 | 1.07 (0.96 - 1.18) | 1.04 (0.94 - 1.16) |
| Model 2 adjusted OR (95% CI) | 1 | 1.22 (1.14 - 1.29) | 1.31 (1.23 - 1.39) | Model 2 adjusted OR (95% CI) | 1 | 1.05 ( 0.94 - 1.16) | 1.01 (0.91 - 1.12) |
| Model 3 adjusted OR (95% CI) | 1 | 1.21 (1.14 - 1.29) | 1.31 (1.23 - 1.39) | Model 3 adjusted OR (95% CI) | 1 | 1.05 ( 0.94 - 1.16) | 1.01 (0.91 - 1.12) |
| Model 4 adjusted OR (95% CI) | 1 | 1.08 (1.00 - 1.16) | 1.05 (0.97 - 1.13) | Model 4 adjusted (OR) (95% CI) | 1 | 0.99 (0.89 - 1.10) | 0.87 (0.78 - 0.97) |
model 1: adjustment for maternal age, gestational age, ethnic background urbanisation, SES.
model 2: model 1 + planned place of birth.
model 3: model 2 + size.
model 4: model 3 + any interventions (pain relief and/or augmentation).