Table 1 Maternal characteristics by gestational age at booking [N = 45,992]
Characteristics | Total |  ≤ 12 weeks |  > 12 weeksa | 13–19 weeksb | 20 weeks and abovec |
|---|---|---|---|---|---|
45,992 | 36,408 (79.2%) | 9584 (20.8%) | 5504 (12.0%) | 4080 (8.8%) | |
Maternal ethnicity | |||||
 White British | 20,029(44.0%) | 16,758(83.7%) | 3271(16.3%) | 1834(9.2%) | 1437(7.2%) |
 White Other | 6875(15.1%) | 4996(72.7%) | 1879(27.3%) | 946(13.8%) | 933(13.6%) |
 Black Caribbean | 880(1.9%) | 623(70.8%) | 257(29.2%) | 164(18.6%) | 93(10.6%) |
 Black African | 2490(5.5%) | 1638(65.8%) | 852(34.2%) | 482(19.4%) | 370(14.9%) |
 Indian | 1708(3.8%) | 1387(81.2%) | 321(18.8%) | 172(10.1%) | 149(8.7%) |
 Pakistani | 7698(16.9%) | 6162(80.0%) | 1536(20.0%) | 1009(13.1%) | 527(6.8%) |
 Bangladeshi | 3037(6.7%) | 2442(80.4%) | 595(19.6%) | 434(14.3%) | 161(5.3%) |
 Any other | 2772(6.1%) | 2048(73.9%) | 724(26.1%) | 384(13.9%) | 340(12.3%) |
Area deprivation quintiles | |||||
 Lowest (least deprived) | 4432(9.7%) | 3469(78.3%) | 963(21.7%) | 425(9.6%) | 538(12.1%) |
 Second lowest | 1893(4.1%) | 1412(74.6%) | 481(25.4%) | 146(7.7%) | 335(17.7%) |
 Middle | 7759(16.9%) | 6395(82.4%) | 1364(17.6%) | 716(9.2%) | 648(8.4%) |
 Second highest | 15,993(34.9%) | 12,893(80.6%) | 3100(19.4%) | 1936(12.1%) | 1164(7.3%) |
 Highest (most deprived) | 15,993(34.3%) | 12,133(77.2%) | 3585(22.8%) | 2256(14.4%) | 1329(8.5%) |
Maternal age (years) | |||||
 ≤ 25 | 13,574(29.5%) | 10,243(75.5%) | 3331(24.5%) | 1879(13.8%) | 1452(10.7%) |
 26–35 | 26,721(58.1%) | 21,686(81.2%) | 5035(18.8%) | 2918(10.9%) | 2117(7.9%) |
 36 and above | 5696(12.4%) | 4478(78.6%) | 1218(21.4%) | 707(12.4%) | 511(9.0%) |
Maternal smoking in pregnancy | |||||
 Non-smokers | 37,057(81.4%) | 29,548(79.7%) | 7509(20.3%) | 4338(11.7%) | 3171(8.6%) |
 Smokers | 8447(18.6%) | 6570(77.8%) | 1877(22.2%) | 1134(13.4%) | 743(8.8%) |
Parity | |||||
 First born | 18,551(40.3%) | 14,342(77.3%) | 4209(22.7%) | 2025(10.9%) | 2184(11.8%) |
 Second | 15,505(33.7%) | 12,820(82.7%) | 2685(17.3%) | 1635(10.5%) | 1050(6.8%) |
 Third | 7194(15.6%) | 5812(80.8%) | 1382(19.2%) | 969(13.5%) | 413(5.7%) |
 Fourth or higher | 4742(10.3%) | 3434(72.4%) | 1308(27.6%) | 875(18.5%) | 433(9.1%) |
Marriage status | |||||
 Married/civil partners | 26,465(57.5%) | 21,272(58.4%) | 5193(54.2%) | 3048(55.4%) | 2145(52.6%) |
 Never married | 3229(7.0%) | 2154(5.9%) | 1075(11.2%) | 648(11.8%) | 427(10.5%) |
 Divorced/separated/widowed | 5788(12.6%) | 4548(12.5%) | 1240(12.9%) | 715(13.0%) | 525(12.9%) |
 Unknown | 10,510(22.9%) | 8434(23.2%) | 2076(21.7%) | 1093(19.8%) | 983(24.1%) |
Migrant status | |||||
 UK born | 8996(58.5%) | 7715(61.2%) | 1281(46.1%) | 741(46.3%) | 540(45.7%) |
 Non-UK born | 6392(41.5%) | 4892(38.8%) | 1500(53.9%) | 858(53.7%) | 642(54.3%) |