Subjects | 148 782 | 259 022 |
Maternal age at delivery years | | |
<25 | 27 156 (10.5) | 21 545 (14.5) |
25–34 | 181 006 (69.9) | 99 489 (66.9) |
≥35 | 50 860 (19.6) | 27 748 (18.6) |
Parity | | |
1 | 62 026 (41.7) | 121 091 (46.7) |
≥2 | 86 756 (58.3) | 137 931 (53.3) |
Maternal smoking during pregnancy | | |
Yes | 24 948 (16.8) | 31 941 (12.3) |
No | 120 709 (81.1) | 221 957 (85.7) |
Unknown | 3125 (2.1) | 5124 (2.0) |
Maternal cohabiting status | | |
Married or cohabiting | 127 215 (85.5) | 227 519 (87.8) |
Single, divorced or widowed | 20 824 (14.0) | 28 114 (10.9) |
Unknown | 743 (0.5) | 3389 (1.3) |
Maternal highest education attained at delivery | | |
Elementary school | 31 122 (20.9) | 37 120 (14.3) |
Above elementary school | 113 206 (76.1) | 211 299 (81.6) |
Unknown | 4454 (3.0) | 10 603 (4.1) |
Maternal diabetes during pregnancy | 4187 (2.8) | 5794 (2.2) |
Premature rupture of membranes | 9109 (6.1) | 16 185 (6.3) |
Caesarean section | 25 955 (17.4) | 42 992 (16.6) |
Maternal atopic disposition | 9427 (6.3) | 11 699 (4.5) |
Paternal atopic disposition | 6910 (4.6) | 11 138 (4.3) |
Paternal antibiotic use during the index pregnancy | 33 028 (22.2) | 42 692 (16.5) |
Preterm birth | 7591 (5.1) | 12 523 (4.8) |
Calendar year of birth | | |
2005–2006 | 41 626 (28.0) | 77 655 (30.0) |
2007–2008 | 43 546 (29.3) | 75 546 (29.2) |
2009–2011 | 63 610 (42.8) | 105 821 (40.9) |