eTable 2. Validation of the pregnancy cohort (2010–2014).
| Year | ||||||
| 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | |
| Pregnancy cohorts *1 | ||||||
| Number of pregnant women | 520 730 | 517 582 | 524 089 | 545 775 | 563 339 | 584 006 |
| Validation cohort (DESTATIS) | ||||||
| Live births *2 | 677 947 | 662 685 | 673 544 | 682 069 | 714 927 | 737 575 |
| Women with twins *3 | 11 573 | 11 254 | 11 648 | 12 119 | 12 977 | 13 368 |
| Women with triplets *3 | 258 | 230 | 230 | 230 | 282 | 258 |
| Women with other multiple births *3 | 7 | 6 | 3 | 6 | 11 | 11 |
| Total multiple births *4 | 12 110 | 11 732 | 12 117 | 12 597 | 13 574 | 13 917 |
| Number of births *2, 3 (live births minus total multiple births) | 665 837 | 650 953 | 661 427 | 669 472 | 701 353 | 723 658 |
|
Difference between validation cohort and pregnancy cohort (number of births *2, 3 minus number of pregnant women *1) | ||||||
| Absolute frequency | 145 107 | 133 371 | 137 338 | 123 697 | 138 014 | 139 652 |
| Relative frequency | 21.8% | 20.5% | 20.8% | 18.5% | 19.7% | 19.3% |
*1 based on the methods used in this study, according to the respective calendar year
*2 German Federal Health Monitoring (GBE-Bund, Gesundheitsberichterstattung des Bundes): Live births (27)
*3 Federal Statistical Office of Germany (DESTATIS, Statistisches Bundesamt): women with multiple births (26)
*4 To prevent overestimation of the number of pregnant women due to multiple births, only one live birth was counted in all cases of multiple birth for the estimation of the number of pregnant women. Therefore, the number of women with multiple births was multiplied by the factor x-multiple births - 1 and then subtracted from the number of live births. So, the total of women with twins × 1, women with triplets × 2 and women with other multiple births × 3 was worked out