Table 3.
Demographic characteristics of ART children, NCS and matched NCP controls born between 1 April 1997 and 31 July 2009
| HFEA-ONS-HES subcohort | ||||
| HES-ART | Control (HES-NCP) | ART with siblings (HES-sART) |
Siblings (HES-NCS) | |
| Infants | 63 877 | 127 544 | 12 329 | 11 343 |
| Follow-up period in days | ||||
| Median (IQR) | 4429 (2181) | 4409 (2141) | 4635 (1846) | 4307 (2029) |
| Mean BW (SD) | ||||
| Singleton | 3166.95 (742.3) | 3271.67 (648.5) | 3222.25 (699.3) | 3346.54 (712.0) |
| Multiple | 2172.27 (715.4) | 2155.77 (683.9) | 2201.58 (724.9) | 2301.17 (677.8) |
| Sex | ||||
| Female | 31 435 (49.2%) | 62 785 (49.2%) | 5907 (47.9%) | 5573 (49.1%) |
| Male | 32 442 (50.8%) | 64 759 (50.8%) | 6422 (52.1%) | 5770 (50.9%) |
| Multiplicity/plurality | ||||
| Singleton | 37 890 (59.4%) | 75 642 (59.3%) | 8383 (68.0%) | 10 815 (95.8%) |
| Twin | 25 987 (40.6%) | 51 902 (40.7%) | 3946 (31.1%) | 528 (4.2%) |
| IMD decile at earliest appointment | ||||
| 1 (most deprived) | 2045 (3.2%) | 12 696 (9.9%) | 349 (2.8%) | 299 (2.6%) |
| 2 | 2650 (4.2%) | 11 104 (8.7%) | 458 (3.7%) | 396 (3.5%) |
| 3 | 3311 (5.2%) | 10 057 (7.8%) | 539 (4.4%) | 463 (4.1%) |
| 4 | 3926 (6.1%) | 9550 (7.5%) | 678 (5.4%) | 588 (5.2%) |
| 5 | 4666 (7.2%) | 9161 (7.5%) | 862 (6.1%) | 746 (6.6%) |
| 6 | 5350 (8.4%) | 8872 (6.5%) | 1084 (8.8%) | 921 (8.1%) |
| 7 | 6142 (9.6%) | 8842 (6.9%) | 1205 (9.8%) | 1044 (9.2%) |
| 8 | 6675 (10.5%) | 8925 (7.0%) | 1299 (10.5%) | 1161 (10.3%) |
| 9 | 7729 (12.1%) | 9083 (7.1%) | 1557 (12.6%) | 1386 (12.2%) |
| 10 (least deprived) | 7710 (12.1%) | 8299 (6.5%) | 1720 (14.0%) | 1499 (13.3%) |
| Missing | 13 673 (21.4%) | 30 955 (24.3%) | 2580 (20.9%) | 2840 (25.0%) |
| Birth year | ||||
| 1997 | 2597 (4.1%) | 5160 (4.1%) | 518 (4.2%) | 242 (2.1%) |
| 1998 | 3708 (5.8%) | 7389 (5.9%) | 743 (6.0%) | 419 (3.7%) |
| 1999 | 4083 (6.4%) | 8126 (6.5%) | 852 (6.9%) | 560 (4.9%) |
| 2000 | 4310 (6.8%) | 8633 (6.9%) | 925 (7.5%) | 781 (6.9%) |
| 2001 | 4559 (7.1%) | 9160 (7.3%) | 972 (7.9%) | 879 (7.78%) |
| 2002 | 4980 (7.8%) | 9933 (7.9%) | 1171 (9.5%) | 937 (8.3%) |
| 2003 | 5379 (8.4%) | 10 788 (8.5%) | 1253 (10.2%) | 1012 (8.9%) |
| 2004 | 5561 (8.7%) | 11 082 (8.7%) | 1271 (10.3%) | 1067 (9.4%) |
| 2005 | 5662 (8.9%) | 11 326 (8.8%) | 1271 (10.3%) | 1078 (9.5%) |
| 2006 | 6275 (9.8%) | 12 513 (9.7%) | 1217 (9.7%) | 1100 (9.7%) |
| 2007 | 6342 (9.9%) | 12 701 (9.8%) | 1058 (8.6%) | 1199 (10.6%) |
| 2008 | 6347 (9.9%) | 12 718 (9.8%) | 670 (5.4%) | 1260 (11.1%) |
| 2009 | 4074 (6.4%) | 8015 (6.2%) | 408 (3.3%) | 809 (7.1%) |
| Ethnicity | ||||
| White | 61 921 (96.9%) | 122 050 (95.7%) | 11 983 (97.2%) | 11 084 (97.7%) |
| Asian/Asian British | 959 (1.5%) | 2496 (1.1%) | 197 (1.6%) | 153 (1.4%) |
| Chinese | 35 (0.1%) | 89 (0.1%) | 8 (0.1%) | 1 (0.0%) |
| Black/African/Caribbean/Black British | 433 (0.7%) | 5268 (4.0%) | 61 (0.5%) | 39 (0.3%) |
| Mixed/multiple ethnic groups | 318 (0.5%) | 721 (0.6%) | 38 (0.3%) | 27 (0.2%) |
| Other ethnic group | 211 (0.3%) | 498 (0.4%) | 42 (0.3%) | 39 (0.3%) |
| Maternal age at delivery | ||||
| ≤25 | 710 (1.1%) | 27 783 (21.9%) | 241 (1.1%) | 317 (2.9%) |
| 25–29 | 5085 (7.1%) | 25 115 (19.7%) | 1209 (9.9%) | 887 (7.8%) |
| 30–34 | 21 994 (34.4%) | 38 896 (30.5%) | 4797 (38.9%) | 3309 (29.1%) |
| 35–39 | 27 682 (43.4%) | 25 907 (20.3%) | 4998 (40.6%) | 4954 (43.7%) |
| 40–44 | 8164 (12.1%) | 6419 (5.2%) | 1057 (8.6%) | 1830 (16.2%) |
| ≥45 | 217 (0.3%) | 772 (0.6%) | 20 (0.2%) | 45 (0.4%) |
| Missing | 25 (0.0%) | 2652 (2.0%) | 7 (0.0%) | 1 (0.0%) |
ART, assisted reproductive technology; BW, birth weight; HES, Hospital Episode Statistics; HFEA, Human Fertilisation and Embryology Authority; ICSI, intracytoplasmic sperm injection; IMD, Index of Multiple Deprivation; IVF, in vitro fertilisation; NCP, Naturally conceived population control; NCS, Naturally conceived siblings; ONS, Office for National Statistics; sART, ART with siblings.