Table 1.
Maternal and paternal characteristics
| Total n (%) | North n (%) | Centre n (%) | South n (%) | P value | |
| Average maternal age at delivery, years; SD | 33.0; 5.3 | 32.9; 5.2 | 33.7; 5.3 | 32.9; 5.6 | 0.0006* |
| Median maternal age at delivery, years; min–max | 33; 16–54 | 33.0; 18–51 | 34; 17–54 | 33; 16–51 | |
| Maternal age class at delivery, years | 0.0052* | ||||
| <25 | 307 (6.2) | 143 (6.2) | 46 (4.8) | 118 (7.1) | |
| 25–29 | 908 (18.4) | 439 (19.0) | 139 (14.6) | 330 (19.8) | |
| 30–34 | 1768 (35.8) | 834 (36.1) | 352 (36.9) | 582 (34.9) | |
| 35–39 | 1432 (29.0) | 665 (28.8) | 307 (32.2) | 460 (27.6) | |
| 40+ | 518 (10.5) | 229 (9.9) | 110 (11.5) | 179 (10.7) | |
| Mother born in Italy | 4357 (86.6) | 1894 (81.1) | 837 (86.5) | 1626 (93.9) | <0.0001* |
| Father born in Italy | 4437 (88.7) | 1950 (83.9) | 841 (87.5) | 1646 (95.8) | <0.0001* |
| Both parents born abroad | 430 (8.6) | 305 (13.1) | 87 (9.1) | 38 (2.2) | <0.0001* |
| Maternal education | <0.0001* | ||||
| Elementary/middle school | 791 (15.7) | 365 (15.8) | 95 (9.8) | 331 (19.4) | |
| High school | 2082 (41.7) | 1020 (44.0) | 337 (34.9) | 725 (42.4) | |
| University | 2123 (42.5) | 933 (40.3) | 535 (55.3) | 655 (38.3) | |
| Maternal employment | 3496 (69.7) | 1740 (74.8) | 747 (76.5) | 1009 (58.8) | <0.0001* |
| Paternal education | <0.0001* | ||||
| Elementary/middle school | 1155 (23.3) | 547 (23.7) | 137 (14.3) | 471 (27.8) | |
| High school | 2471 (50.0) | 1191 (51.8) | 454 (47.5) | 826 (48.8) | |
| University | 1319 (26.7) | 561 (24.4) | 364 (38.1) | 394 (23.3) | |
| Paternal employment | 4796 (96.1) | 2281 (98.4) | 929 (96.2) | 1586 (93.1) | <0.0001* |
| Maternal civil status | <0.0001* | ||||
| Married/living together | 4772 (95.7) | 2222 (96.0) | 897 (93.0) | 1653 (96.9) | |
| Single/separated/divorced/widow | 213 (4.3) | 92 (4.0) | 68 (7.0) | 53 (3.1) | |
| Child living with both parents | 4950 (98.2) | 2306 (98.6) | 957 (98.0) | 1687 (97.6) | 0.0548 |
* Statistically significant