Table 2.
Unadjusted and adjusted results obtained from regressions assessing the relationship of CS and characteristics of pregnant women with perinatal mortality
| Characteristics | Perinatal mortality | Relative risks (95% CI) | P value‡ | ||
| Yes n=160 (4.1%) |
No n=37 417 (95.9%) |
Unadjusted* | Adjusted† | ||
| N (row %) | |||||
| Caesarean section | <0.001 | ||||
| Yes | 203 (2.7) | 7437 (97.3) | 0.61 (0.52 to 0.70) | 0.65 (0.56 to 0.76) | |
| No | 1406 (4.5) | 29 980 (95.5) | Referent | Referent | |
| Time in years | 0.02 | ||||
| 2010 | 448 (4.5) | 9619 (95.5) | Referent | Referent | |
| 2011 | 344 (3.6) | 9203 (96.4) | 0.81 (0.70 to 0.93) | 0.84 (0.73 to 0.97) | |
| 2012 | 389 (4.1) | 9118 (95.9) | 0.92 (0.80 to 1.05) | 1.00 (0.87 to 1.15) | |
| 2103 | 428 (4.3) | 9477 (95.7) | 0.97 (0.85 to 1.11) | 1.04 (0.91 to 1.18) | |
| Mother’s age (years) | <0.01 | ||||
| <25 | 1083 (4.1) | 25 562 (95.9) | Referent | Referent | |
| 25+ | 526 (4.2) | 11 855 (95.8) | 1.05 (0.94 to 1.16) | 1.20 (1.07 to 1.35) | |
| Parity | <0.001 | ||||
| Nulliparous | 858 (4.6) | 17 878 (95.4) | 1.24 (1.13 to 1.37) | 1.52 (1.36 to 1.70) | |
| Multiparous | 751 (3.7) | 19 539 (96.3) | Referent | Referent | |
| Mother’s education* | <0.01 | ||||
| None/primary | 393 (4.9) | 7577 (95.1) | Referent | Referent | |
| Secondary | 982 (4.2) | 22 203 (95.8) | 0.84 (0.75 to 0.94) | 0.94 (0.84 to 1.06) | |
| University | 233 (3.0) | 7579 (97.0) | 0.60 (0.51 to 0.70) | 0.75 (0.63 to 0.88) | |
| BMI categories (kg/m*)§ | 0.09 | ||||
| <18.5 | 618 (4.6) | 12 891 (95.4) | 1.15 (1.04 to 1.28) | 1.12 (1.01 to 1.24) | |
| 18.5–24.9 | 933 (3.9) | 23 106 (96.1) | Referent | Referent | |
| 25.0+ | 57 (3.9) | 1385 (96.1) | 1.03 (0.79 to 1.35) | 1.14 (0.87 to 1.49) | |
| Anaemia (haemoglobin g/dL) | 0.03 | ||||
| None (≥11.0) | 107 (3.2) | 3275 (96.8) | Referent | Referent | |
| Mild (10.0–10.9) | 626 (3.8) | 15 659 (96.2) | 1.22 (1.00 to 1.50) | 1.15 (0.93 to 1.41) | |
| Moderate or severe (<10.0) | 876 (4.5) | 18 483 (95.5) | 1.44 (1.17 to 1.76) | 1.27 (1.03 to 1.56) | |
| Multiple gestation | <0.001 | ||||
| No | 1544 (4.0) | 37 173 (96.0) | Referent | Referent | |
| Yes | 65 (21.0) | 244 (79.0) | 5.22 (4.07 to 6.71) | 2.30 (1.79 to 2.96) | |
| Gestational age at birth§ | <0.001 | ||||
| Preterm | 844 (15.2) | 4724 (84.8) | 6.72 (5.98 to 7.56) | 6.34 (5.64 to 7.12) | |
| Term | 738 (2.2) | 32 311 (97.8) | Referent | Referent | |
*Obtained from single variable Poisson regressions solved by GEE adjusting for clusters.
†Obtained from multivariable Poisson model solved by GEE adjusting for clusters. Model Included CS, time in years, maternal age, parity, education, BMI, anaemia status, multiple gestation and gestational age at birth.
‡Obtained from multivariable models.
§Overall missing was <0.1% to 0.9%.
BMI, body mass index; CS, caesarean section; GEE, generalised estimating equation.