Table 4.
Multivariable logistic regression models for the odds of cesarean delivery incorporating both surveys, (a) without and (b) with adjustment for maternal somatic phenotype.
| (a) Unadjusted for maternal phenotype | (b) Adjusted for maternal phenotype | ||||||
|---|---|---|---|---|---|---|---|
| Nagelkerke r2 = 0.201 | Nagelkerke r2 = 0.224 | ||||||
| Predictor | N | OR | 95% CI | p | OR | 95% CI | p |
| SURVEY | |||||||
| 2005–2006 (ref) | 42,184 | 1.0 | 1.0 | ||||
| 2015–2016 | 227,329 | 1.49 | 1.44, 1.55 | <0.0001 | 1.40 | 1.35, 1.45 | <0.0001 |
| MATERNAL NUTRITIONAL STATUS | |||||||
| Normal height normal BMI (ref) | 151,355 | 1.0 | – | – | |||
| Overweight | 36,842 | 1.65 | 1.62, 1.73 | <0.0001 | |||
| Obese | 14,883 | 3.00 | 2.88, 3.13 | <0.0001 | |||
| Short | 52,727 | 1.37 | 1.32, 1.42 | <0.0001 | |||
| Short overweight | 10,036 | 2.32 | 2.20, 2.46 | <0.0001 | |||
| Short obese | 3,670 | 3.57 | 3.31, 3.86 | <0.0001 | |||
| MATERNAL AGE | |||||||
| 15–19 years (ref) | 7,853 | 1.0 | – | – | 1.0 | – | – |
| 20–24 years | 82,554 | 1.23 | 1.14, 1.33 | <0.0001 | 1.20 | 1.11, 1.30 | <0.0001 |
| 25–29 years | 102,384 | 1.71 | 1.58, 1.84 | <0.0001 | 1.57 | 1.45, 1.69 | <0.0001 |
| 30–34 years | 50,447 | 2.66 | 2.46, 2.89 | <0.0001 | 2.25 | 2.08, 2.44 | <0.0001 |
| 35–39 years | 19,399 | 3.62 | 3.13, 3.96 | <0.0001 | 2.91 | 2.66, 3.19 | <0.0001 |
| 40–44 years | 5,388 | 4.44 | 3.92, 5.03 | <0.0001 | 3.46 | 3.05, 3.93 | <0.0001 |
| 45–49 years | 1,488 | 3.10 | 2.39, 4.03 | <0.0001 | 2.50 | 1.92, 3.27 | <0.0001 |
| BIRTH NUMBER WITHIN SURVEY | |||||||
| Most recent birth within 5 years (ref) | 203,546 | 1.0 | – | – | 1.0 | – | – |
| 2nd most recent birth within 5 years | 59,484 | 0.49 | 0.47, 0.50 | <0.0001 | 0.49 | 0.48, 0.51 | <0.0001 |
| 3rd most recent birth within 5 years | 6,483 | 0.22 | 0.19, 0.25 | <0.0001 | 0.22 | 0.19, 0.25 | <0.0001 |
| WEALTH INDEX | |||||||
| Level 1 (ref) | 66,038 | 1.0 | – | – | 1.0 | – | – |
| Level 2 | 61,064 | 1.89 | 1.79, 1.99 | <0.0001 | 1.82 | 1.72, 1.92 | <0.0001 |
| Level 3 | 54,414 | 3.42 | 3.25, 3.59 | <0.0001 | 3.14 | 2.98, 3.30 | <0.0001 |
| Level 4 | 47,858 | 4.71 | 4.48, 4.95 | <0.0001 | 4.15 | 3.94, 4.36 | <0.0001 |
| Level 5 (wealthiest) | 40,139 | 6.18 | 5.87, 6.51 | <0.0001 | 5.12 | 4.85, 5.40 | <0.0001 |
| RESIDENCE | |||||||
| Rural (ref) | 199,457 | 1.0 | – | – | 1.0 | – | – |
| Urban | 70,056 | 1.26 | 1.23, 1.30 | <0.0001 | 1.20 | 1.17, 1.23 | <0.0001 |
| BIRTH ORDER | |||||||
| First-born | 98,478 | 16.9 | 14.7, 19.5 | <0.0001 | 16.38 | 14.2, 18.84 | <0.0001 |
| Second-born | 82,692 | 9.37 | 8.2, 10.8 | <0.0001 | 8.92 | 7.76, 10.25 | <0.0001 |
| Third-born | 43,103 | 4.33 | 3.76, 4.98 | <0.0001 | 4.10 | 3.56, 4.72 | <0.0001 |
| Fourth-born | 21,920 | 2.07 | 1.78, 2.42 | <0.0001 | 2.00 | 1.71, 2.33 | <0.0001 |
| Fifth-born | 11,193 | 1.46 | 1.22, 1.75 | <0.0001 | 1.43 | 1.20, 1.71 | <0.0001 |
| Sixth+-born (ref) | 12,127 | 1.0 | – | – | 1.0 | – | – |
| OFFSPRING SEX | |||||||
| Female (ref) | 129,076 | 1.0 | – | – | 1.0 | – | – |
| Male | 140,437 | 1.03 | 1.00, 1.05 | 0.016 | 1.04 | 1.01, 1.06 | 0.003 |
Total N, 275,271; OR, Odds Ratio; Ref, reference group. All coefficients are calculated relative to all other variables in the table, entered into a single logistic regression model.