Table 1 Screening, exclusion and outcome characteristics for analysis population from 2017 – 2020

Screened, N

179,953

24,914

22,184

26,881

30,010

23,986

23,274

23,112

5,592

 Ineligible, N (%)

244 (0.1)

0 (0.0)

0 (0.0)

0 (0.0)

0 (0.0)

0 (0.0)

0 (0.0)

0 (0.0)

244 (4.4)

 Did not consent, N (%)

224 (0.1)

0 (0.0)

0 (0.0)

1 (0.0)

202 (0.7)

3 (0.0)

0 (0.0)

0 (0.0)

18 (0.3)

 Lost to follow-up prior to delivery or missing delivery outcome, N (%)

2,162 (1.2)

258 (1.0)

66 (0.3)

1,387 (5.2)

239 (0.8)

5 (0.0)

60 (0.3)

104 (0.4)

43 (0.8)

Delivered, N (% of screened)

177,323 (98.5)

24,656 (99.0)

22,118 (99.7)

25,493 (94.8)

29,569 (99.2)

23,978 (100.0)

23,214 (99.7)

23,008 (99.6)

5,287 (99.2)

 Excluded ^a, N (%)

32,117 (18.1)

2,342 (9.5)

2,668 (12.1)

2,886 (11.3)

4,697 (15.9)

8,365 (34.9)

3,593 (15.5)

7,144 (31.1)

422 (8.0)

  Did not meet singleton livebirth / fresh stillbirth criteria, N (%)

12,900 (7.3)

1,127 (4.6)

515 (2.3)

832 (3.3)

918 (3.1)

4,551 (19.0)

1,950 (8.4)

2,715 (11.8)

292 (5.5)

   Maternal death prior to delivery, N (%)

94 (0.1)

29 (0.1)

9 (0.0)

13 (0.1)

8 (0.0)

7 (0.0)

9 (0.0)

18 (0.1)

1 (0.0)

   Miscarriage, N (%)

7,162 (4.0)

237 (1.0)

136 (0.6)

241 (0.9)

571 (1.9)

2,829 (11.8)

1,033 (4.4)

1,914 (8.3)

201 (3.8)

   MTP, N (%)

2,392 (1.3)

43 (0.2)

4 (0.0)

21 (0.1)

15 (0.1)

1,424 (5.9)

629 (2.7)

247 (1.1)

9 (0.2)

   Macerated stillbirth or stillbirth type unknown, N (%)

1,487 (0.8)

396 (1.6)

138 (0.6)

202 (0.8)

131 (0.4)

139 (0.6)

126 (0.5)

331 (1.4)

24 (0.5)

   Multiples, N (%)

1,804 (1.1)

435 (1.8)

235 (1.1)

361 (1.4)

194 (0.7)

155 (0.8)

156 (0.7)

210 (1.0)

58 (1.1)

  Excluded due to missing variables, n (% of those with no other exclusions)

19,217 (11.7)

1,215 (5.2)

2,153 (10.0)

2,054 (8.3)

3,779 (13.2)

3,814 (19.6)

1,643 (7.7)

4,429 (21.8)

130 (2.6)

   LBW status missing, N (%)

234 (0.1)

15 (0.1)

7 (0.0)

54 (0.2)

44 (0.2)

10 (0.1)

29 (0.1)

23 (0.1)

52 (1.0)

   Missing any of the predictive model covariates, N (%)

19,117 (11.6)

1,208 (5.1)

2,153 (10.0)

2,028 (8.2)

3,779 (13.2)

3,812 (19.6)

1,626 (7.7)

4,425 (21.8)

86 (1.7)

Analysis population, N (% of delivered)

145,206 (81.9)

22,314 (90.5)

19,450 (87.9)

22,607 (88.7)

24,872 (84.1)

15,613 (65.1)

19,621 (84.5)

15,864 (68.9)

4,865 (92.0)

 Fresh stillbirth, N (%)

2,268 (1.6)

416 (1.9)

205 (1.1)

340 (1.5)

354 (1.4)

220 (1.4)

225 (1.1)

449 (2.8)

59 (1.2)

  LBW

1,282 (56.5)

195 (46.9)

98 (47.8)

131 (38.5)

216 (61.0)

180 (81.8)

174 (77.3)

252 (56.1)

36 (61.0)

 Livebirth, N (%)

142,938 (98.4)

21,898 (98.1)

19,245 (98.9)

22,267 (98.5)

24,518 (98.6)

15,393 (98.6)

19,396 (98.9)

15,415 (97.2)

4,806 (98.8)

  LBW

18,699 (13.1)

2,146 (9.8)

1,148 (6.0)

720 (3.2)

4,096 (16.7)

2,944 (19.1)

3,687 (19.0)

3,062 (19.9)

896 (18.6)

 Total LBW, N (%)

19,981 (13.8)

2,341 (10.5)

1,246 (6.4)

851 (3.8)

4,312 (17.3)

3,124 (20.0)

3,861 (19.7)

3,314 (20.9)

932 (19.2)