Multiple logistic regression model results for the significant risk factors on univariate analysis
| Variable | Adjusted OR (from multiple logistic regression model)* | Crude OR (from univariate analysis) | ||||
| OR | 95% C.I. | OR | 95% C.I. | |||
| Lower | Upper | Lower | Upper | |||
| Consanguinity, none (reference group) | – | – | – | – | – | – |
| Consanguinity, first degree | 1.52 | 1.28 | 1.81 | 1.53 | 1.30 | 1.81 |
| Maternal age, 20–30 years (reference group) | – | – | – | – | – | – |
| Maternal age, <20 years | 0.54 | 0.32 | 0.91 | 0.58 | 0.35 | 0.96 |
| Maternal age, >40 years | 2.11 | 1.35 | 3.30 | 2.09 | 1.43 | 3.05 |
| Maternal education, up to high school (reference group) | – | – | – | – | – | – |
| Maternal education, illiterate | 1.41 | 1.17 | 1.70 | 1.50 | 1.26 | 1.80 |
| Maternal education, university | 1.74 | 1.24 | 2.44 | 2.05 | 1.49 | 2.81 |
| Diabetes on insulin, overt or gestational (yes/no) | 1.98 | 1.33 | 2.95 | 2.34 | 1.60 | 3.43 |
| Sibling with anomalies (yes/no) | 1.49 | 1.04 | 2.12 | 1.61 | 1.14 | 2.27 |
*Adjustment for consanguinity, maternal age, maternal education, diabetes mellitus, sibling with anomalies.