| Institutional rates of maternal characteristics (%) | Median | IQR | Median | IQR | Median | IQR | Median | IQR | ANOVA p value |
| Maternal age <20 years | 1.8 | 0.7–19.8 | 11.6 | 6.1–22.7 | 5.8 | 2.6, 13.0 | 11.5 | 2.8, 17.5 | 0.08 |
| Maternal age ≥35 years | 22.1 | 11.7–29.9 | 13.2 | 9.8–15.2 | 9.4 | 6.0, 13.4 | 10.8 | 8.4, 16.4 | <0.001 |
| Unmarried | 10.4 | 2.4–23.4 | 10.3 | 0.7–18.3 | 1.9 | 0.3, 10.6 | 4.4 | 1.0, 15.4 | 0.02 |
| Education <6 years | 63.1 | 32.7–69.1 | 63.6 | 41.2–75.9 | 69.8 | 49.3, 78.6 | 66.7 | 56.5, 85.1 | <0.001 |
| Primiparous | 51.6 | 42.3–58.7 | 45.6 | 39.8–50.1 | 48.8 | 43.9, 54.9 | 34.4 | 28.8, 39.4 | 0.004 |
| Previous caesarean delivery | 9.4 | 6.1–15.9 | 15.8 | 10.0–21.5 | 9.6 | 5.3, 13.5 | 9.8 | 5.6, 18.0 | <0.001 |
ANOVA, analysis of variance; HDI, Human Development Index.