TABLE 1

Baseline Characteristics of the Study Population

CharacteristicsART ChildrenNon-ART ChildrenTotal
Total number of persons25 7821 602 8761 628 658
Persons with cancer, n4944144463
Age at cancer diagnosis, median (IQR)3.2 (1.9–7.7)8.8 (3.1–17.4)8.7 (3.0–17.3)
Follow-up time,a median (IQR)6.9 (3.1–12.0)13.7 (6.5–20.5)13.5 (6.5–20.5)
Total follow-up time, person-years205 52921 807 10822 012 552
Birth year, n (%)
 1984–19932097 (8)562 833 (35)564 930 (35)
 1994–20039313 (36)577 093 (36)586 406 (36)
 2004–201114 372 (56)462 950 (29)477 322 (29)
 Total25 782 (100)1 602 876 (100)1 628 658 (100)
Gender, n (%)
 Male12 594 (49)823 300 (51)835 894 (51)
 Female13 188 (51)779 576 (49)792 764 (49)
 Total25 782 (100)1 602 876 (100)1 628 658 (100)
Multiple or singleton birth, n (%)
 Multiple birth8432 (33)41 199 (3)49 631 (3)
 Singleton17 350 (67)1 561 677 (97)1 579 027 (97)
 Total25 782 (100)1 602 876 (100)1 628 658 (100)
Birth weight, g, median (IQR)3220 (2670–3670)3550 (3200–3900)3550 (3196–3900)
 <2900, n (%)8739 (34)185 896 (12)194 635 (12)
 2900–4100, n (%)14 849 (58)1 177 308 (73)1 192 157 (73)
 ≥4100, n (%)2167 (8)238 188 (15)240 355 (15)
 Missing, n (%)27 (0)1484 (0)1511 (0)
 Total, n (%)25 782 (100)1 602 876 (100)1 628 658 (100)
Gestational length, wk, median (IQR)39 (37–40)40 (39–41)40 (39–41)
 <24, n (%)74 (0)642 (0)716 (0)
 24–30, n (%)516 (2)7055 (0)7571 (0)
 30–35, n (%)2110 (8)31 540 (2)33 650 (2)
 36–42, n (%)19 903 (77)1 323 206 (83)1 343 109 (82)
 Over 42, n (%)1095 (4)158 513 (10)159 608 (10)
 Missing2084 (8)81 920 (5)84 004 (5)
 Total25 782 (100)1 602 876 (100)1 628 658 (100)
Method of ART, n (%)
 Classic IVF15 170 (59)
 ICSI7798 (30)
 Other188 (1)
 Missing2626 (10)
 Total25 782(100)
Maternal age at delivery, median (IQR)33.0 (30.0–36.0)28.0 (25.0–32.0)28.0 (25.0–32.0)
 <25, n (%)409 (2)369 653 (23)370 062 (23)
 25–29, n (%)4823 (19)563 005 (35)567 828 (35)
 30–35, n (%)11 397 (44)457 485 (29)468 882 (29)
 >35, n (%)9152 (35)212 711 (13)221 863 (14)
 Missing, n (%)1 (0)22 (0)23 (0)
 Total, n (%)25 782 (100)1 602 876 (100)1 628 658 (102)
Birth order, n (%)
 116 792 (65)663 704 (41)680 496 (42)
 27371 (29)569 706 (36)577 077 (35)
 31254 (5)265 000 (17)266 254 (16)
 4276 (1)72 999 (5)73 275 (4)
 ≥589 (0)31 466 (2)31 555 (2)
 Missing0 (0)1 (0)1 (0)
 Total25 782 (100)1 602 876 (100)1 628 658 (100)
Age at cancer diagnosis, y, n (%)
 <529 (64)1637 (36)1666 (37)
 5–1012(26)719 (16)731 (16)
 10–154 (8)598 (13)602 (13)
 15–204 (8)724 (16)728 (16)
 >200 (0)736 (16)736 (16)
 Total49 (106)4414 (97)4463 (100)
Birthplace (Health Region of Norway), n (%)
 Southeast8493 (33)543 113 (34)551 606 (34)
 Oslo3677 (14)217 945 (14)221 622 (14)
 Southwest4744 (18)244 687 (15)249 431 (15)
 West4243 (16)288 305 (18)292 548 (18)
 Middle2700 (10)140 730 (9)143 430 (9)
 North1917 (7)167 037 (10)168 954 (10)
 Missing8 (0)1059 (0)1067 (0)
 Total25 782 (100)1 602 876 (100)1 628 658 (100)
  • ART children are those registered as conceived by ART in the MBRN; non-ART children are those registered as not conceived by ART. IQR, interquartile range.

  • a This is equal to the age of study subjects at end of follow-up or censoring.