Table 1. Baseline Characteristics of the Study Population.
| Characteristic | No. (%)a | |||
|---|---|---|---|---|
| Preeclampsia (n = 188 670) | Gestational hypertension (n = 104 595) | Chronic hypertension (n = 37 854) | Normotensive pregnancy (n = 8 150 357) | |
| Offspring characteristics | ||||
| Country of birth | ||||
| Denmark | 72 259 (38.3) | 25 884 (24.8) | 12 990 (34.3) | 2 561 557 (31.4) |
| Finland | 31 265 (16.6) | 44 883 (42.9) | 15 782 (41.7) | 1 545 850 (19.0) |
| Sweden | 85 146 (45.1) | 33 828 (32.3) | 9 082 (24.0) | 4 042 950 (49.6) |
| Calendar year of birth | ||||
| 1973-1978 | 4 839 (2.6) | 2 359 (2.3) | 111 (0.3) | 984 271 (12.1) |
| 1979-1984 | 14 964 (7.9) | 7 337 (7.0) | 647 (1.7) | 843 101 (10.3) |
| 1985-1990 | 29 073 (15.4) | 13 376 (12.8) | 2 088 (5.5) | 1 176 830 (14.4) |
| 1991-1996 | 36 688 (19.5) | 14 959 (14.3) | 3 829 (10.1) | 1 358 034 (16.7) |
| 1997-2002 | 30 628 (16.2) | 17 847 (17.0) | 8 197 (21.7) | 1 168 678 (14.4) |
| 2003-2008 | 32 514 (17.2) | 22 494 (21.5) | 10 762 (28.4) | 1 239 011 (15.2) |
| 2009-2016 | 39 964 (21.2) | 26 223 (25.1) | 12 220 (32.3) | 1 380 432 (16.9) |
| Sex | ||||
| Boy | 97 912 (51.9) | 55 088 (52.7) | 19 368 (51.2) | 4 180 198 (51.3) |
| Girl | 90 731 (48.1) | 49 496 (47.3) | 18 468 (48.8) | 3 967 887 (48.7) |
| Unknown | 27 (0.01) | 11 (0.01) | 0 | 1 272 (0.02) |
| Any congenital anomaly | ||||
| No | 165 504 (87.7) | 94 340 (90.2) | 33 618 (88.8) | 7 413 915 (91.0) |
| Yes | 23 166 (12.3) | 10 255 (9.8) | 4 236 (11.2) | 736 442 (9.0) |
| Preterm birth (<37 gestational wk) | ||||
| No | 146 684 (79.8) | 96 845 (93.9) | 33 622 (89.4) | 7 380 747 (95.6) |
| Yes | 37 199 (20.2) | 6 245 (6.1) | 4 236 (10.6) | 338 544 (4.4) |
| SGAb | ||||
| No | 137 359 (75.1) | 86 258 (83.9) | 31 352 (83.6) | 6 960 459 (90.5) |
| Yes | 45 512 (24.9) | 16 532 (16.1) | 6 127 (16.4) | 734 328 (9.5) |
| Maternal characteristics | ||||
| Country of origin same as the country of birthc | ||||
| No | 14 625 (9.3) | 3 985 (6.7) | 2 011 (9.1) | 773 582 (11.7) |
| Yes | 142 655 (90.6) | 55 676 (93.2) | 20 053 (90.8) | 5 818 534 (88.1) |
| Unknown | 125 (0.1) | 51 (0.1) | 8 (0.1) | 12 391 (0.2) |
| Age at delivery, y | ||||
| ≤19 | 6 005 (3.2) | 2 016 (1.9) | 159 (0.4) | 240 677 (3.0) |
| 20-24 | 38 019 (20.1) | 16 066 (15.4) | 2 362 (6.3) | 1 588 783 (19.5) |
| 25-29 | 63 596 (33.7) | 33 059 (31.6) | 8 433 (22.3) | 2 870 923 (35.2) |
| 30-34 | 50 121 (26.6) | 31 014 (29.7) | 13 036 (34.4) | 2 322 255 (28.5) |
| ≥35 | 30 929 (16.4) | 22 440 (21.4) | 13 864 (36.6) | 1 127 677 (13.8) |
| Unknown | 0 | 0 | 0 | 42 (<0.01) |
| Educational level before delivery | ||||
| Primary and lower secondary | 33 476 (17.7) | 10 782 (10.3) | 3 406 (9.00) | 1 457 757 (17.9) |
| Upper secondary | 95 118 (50.4) | 56 157 (53.7) | 20 344 (53.7) | 3 950 516 (48.5) |
| ≥Bachelor’s degree | 54 636 (29.0) | 32 702 (31.3) | 12 475 (33.0) | 2 424 645 (29.7) |
| Unknown | 5 440 (2.9) | 4 954 (4.7) | 1 629 (4.3) | 317 439 (3.9) |
| Marital status before delivery | ||||
| Not married/registered partnership | 99 690 (52.8) | 48 206 (46.1) | 16 176 (42.7) | 3 530 821 (43.3) |
| Married/registered partnership | 87 549 (46.4) | 54 953 (52.5) | 21 241 (56.1) | 4 413 610 (54.2) |
| Unknown | 1 431(0.8) | 1 436 (1.4) | 437 (1.2) | 205 926 (2.5) |
| Parity | ||||
| 1 | 124 795 (66.2) | 63 862 (61.1) | 16 444 (43.4) | 3 779 841 (46.4) |
| 2 | 40 078 (21.2) | 23 222 (22.2) | 11 473 (30.3) | 2 747 272 (33.7) |
| ≥3 | 23 648 (12.5) | 17 415 (16.6) | 9 917 (26.2) | 1 618 740 (19.8) |
| Unknown | 149 (0.1) | 96 (0.1) | 20 (0.1) | 4 504 (0.1) |
| Smoking status during early pregnancy | ||||
| No | 131 126 (69.5) | 78 637 (75.2) | 31 602 (83.5) | 4 818 311 (59.1) |
| Yes | 22 376 (11.9) | 13 107 (12.5) | 4 247 (11.2) | 1 151 939 (14.1) |
| Unknown | 35 168 (18.6) | 12 851 (12.3) | 2 005 (5.3) | 2 180 107 (26.8) |
| BMI during early pregnancyc | ||||
| <18.5 | 1 928 (1.2) | 665 (1.1) | 280 (1.3) | 126 702 (1.9) |
| 18.5-24.9 | 40 931 (26.0) | 16 660 (27.8) | 6 417 (29.1) | 1 966 797 (29.8) |
| 25.0-29.9 | 25 931 (16.5) | 10 640 (17.8) | 4 236 (19.2) | 740 266 (11.2) |
| ≥30.0 | 19 221 (12.2) | 7 946 (13.3) | 4 274 (19.3) | 303 743 (4.6) |
| Unknown | 69 394 (44.1) | 23 861 (40.0) | 6 865 (31.1) | 3 466 999 (52.5) |
| Diabetes status before delivery | ||||
| No | 178 599 (94.7) | 96 612 (92.4) | 31 197 (82.4) | 7 959 279 (97.7) |
| Yes | 10 071 (5.3) | 7 983 (7.6) | 6 657 (17.6) | 191 078 (2.3) |
| Family history of CVDsc | ||||
| No | 115 739 (73.5) | 41 675 (69.8) | 12 300 (55.7) | 5 221 193 (79.0) |
| Yes | 41 666 (26.5) | 18 037 (30.2) | 9 772 (44.3) | 1 383 314 (21.0) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); CVDs, cardiovascular diseases; SGA, small for gestational age.
a
Some individuals were exposed to more than 1 subtype of hypertension.
b
SGA was defined as birth weight below the 10th percentile of the sex-specific and gestational age–specific standard curve for normal fetal growth.
c
These covariates were only available in Sweden and Denmark.