Table 1 Socio-demographic characteristics of included population
|  | Total population (n) | First trimester booking (0–13 weeks) (n, %) | Second trimester booking (14–28 weeks) (n, %) | Third trimester booking (29–44 weeks) (n, %) | p |
|---|---|---|---|---|---|
BMI Group | Â | Â | Â | Â | <0.001 |
 Underweight | 19,393 | 11,919 (3.4%) | 6795 (2.9%) | 679 (2.2%) |  |
 Recommended | 346,347 | 202,434 (56.9%) | 129,353 (55.4%) | 14,560 (47.7%) |  |
 Overweight | 163,282 | 90,431 (25.4%) | 63,160 (27.1%) | 9691 (31.8%) |  |
 Obese | 90,480 | 50,862 (14.3%) | 34,053 (14.6%) | 5565 (18.2%) |  |
Age Group (years) | Â | Â | Â | Â | <0.001 |
  < 18 | 12,803 | 6230 (1.8%) | 5657 (2.4%) | 916 (3.0%) |  |
 18–24 | 147,198 | 78,926 (22.2%) | 59,986 (25.8%) | 8286 (27.2%) |  |
 25–30 | 207,699 | 120,695 (34.0%) | 77,037 (33.1%) | 9967 (32.8%) |  |
  > 30 | 250,177 | 148,882 (42.0%) | 90,047 (38.7%) | 11,248 (37.0%) |  |
Teenage Pregnancy | Â | Â | Â | Â | <0.001 |
 Yes | 12,803 | 6230 (1.8%) | 5657 (2.4%) | 916 (3.0%) |  |
 No | 605,074 | 348,503 (98.2) | 227,070 (97.6%) | 29,501 (97.0%) |  |
Parity | Â | Â | Â | Â | <0.001 |
 0 | 215,609 | 126,119 (36.4%) | 77,817 (34.2%) | 11,673 (40.2%) |  |
 1 | 215,331 | 125,918 (36.4%) | 79,939 (35.1%) | 9474 (32.6%) |  |
 2 | 102,061 | 57,908 (16.7%) | 39,761 (17.5%) | 4392 (15.1%) |  |
 3+ | 69,552 | 36,076 (10.4%) | 29,951 (13.2%) | 3525 (12.1%) |  |
Ethnicity | Â | Â | Â | Â | <0.001 |
 White | 447,550 | 278,187 (88.2%) | 149,341 (76.2%) | 20,022 (74.5%) |  |
 South Asian or Asian British | 50,762 | 21,066 (6.7%) | 26,957 (13.8%) | 2739 (10,2%) |  |
 Black or Black British | 22,531 | 7571 (2.4%) | 12,309 (6.3%) | 2651 (9.9%) |  |
 Chinese or Other Ethnic Group | 11,399 | 5441 (1.7%) | 4893 (2.5%) | 1065 (4.0%) |  |
 Mixed | 5966 | 3174 (1.0%) | 2394 (1.2%) | 398 (1.5%) |  |
Employment | Â | Â | Â | Â | <0.001 |
 Employed | 262,556 | 167,707 (67.9%) | 84,809 (57.8%) | 10,040 (52.2%) |  |
 Higher Education | 8047 | 3845 (1.6%) | 3670 (2.5%) | 532 (2.8%) |  |
 Housewife/ Carer | 92,938 | 49,221 (19.9%) | 38,463 (26.2%) | 5254 (27.3%) |  |
 Not employed | 44,430 | 23,867 (9.7%) | 17,595 (12.0%) | 2968 (15.4%) |  |
 School Age/ Education under 18 years | 5092 | 2387 (1.0%) | 2273 (1.5%) | 432 (2.2%) |  |
IMD Quintile | Â | Â | Â | Â | <0.001 |
 5- Least Deprived | 125,474 | 79,022 (22.7%) | 40,342 (18.5%) | 6110 (20.8%) |  |
 4 | 104,106 | 65,862 (18.9%) | 33,490 (15.3%) | 4754 (16.2%) |  |
 3 | 110,058 | 65,790 (18.9%) | 39,060 (17.9%) | 5208 (17.8%) |  |
 2 | 119,657 | 65,653 (18.9%) | 47,590 (21.8%) | 6414 (21.9%) |  |
 1- Most Deprived | 136,404 | 71,493 (20.6%) | 58,058 (26.6%) | 6853 (23.4%) |  |