Table 2. Ethnicity, personal antecedents, pre-existing diseases and type of delivery of the study population.
| Characteristics | First trimester | Second trimester | Third trimester | |||
|---|---|---|---|---|---|---|
| n/N | (%) | n/N | (%) | n/N | (%) | |
| Ethnicity | ||||||
| White | 514/1,102 | (46.6) | 308/683 | (45.1) | 386/893 | (43.2) |
| Black | 155/1,102 | (14.1) | 106/683 | (15.5) | 137/893 | (15.3) |
| East Asian | 8/1,102 | (0.7) | 5/683 | (0.7) | 3/893 | (0.3) |
| South Asian | 0/1,102 | (0) | 1/683 | (0.1) | 1/893 | (0.1) |
| Mixed | 298/1,102 | (27.0) | 215/683 | (31.5) | 275/893 | (30.8) |
| Not informed | 127/1,102 | (11.5) | 48/683 | (7.0) | 91/893 | (10.2) |
| Smoking | ||||||
| Yes | 52/1,102 | (4.7) | 46/683 | (6.7) | 83/893 | (9.3) |
| No | 997/1,102 | (90.5) | 630/683 | (92.2) | 787/893 | (88.1) |
| Quit | 1/1,102 | (0.1) | 1/683 | (0.1) | 2/893 | (0.2) |
| Not informed | 52/1,102 | (4.7) | 6/683 | (0.9) | 21/893 | (2.4) |
| Alcohol | ||||||
| Yes | 10/1,102 | (0.9) | 13/683 | (1.9) | 19/893 | (2.1) |
| No | 1033/1,102 | (93.7) | 660/683 | (96.6) | 849/893 | (95.1) |
| Quit | 4/1,102 | (0.4) | 3/683 | (0.4) | 2/893 | (0.2) |
| Not informed | 55/1,102 | (5.0) | 7/683 | (1.0) | 23/893 | (2.6) |
| Folic acid (before pregnancy) | ||||||
| Yes | 92/1,102 | (8.3) | 42/683 | (6.1) | 54/893 | (6.0) |
| No or not informed | 1010/1,102 | (91.7) | 641/683 | (93.9) | 839/893 | (94.0) |
| Folic acid (during pregnancy) | ||||||
| Yes | 666/1,102 | (60.4) | 383/683 | (56.1) | 429/893 | (48.0) |
| No or not informed | 436/1,102 | (39.6) | 300/683 | (43.9) | 464/893 | (52.0) |
| Diabetes mellitus | ||||||
| Type 1 | 3/1,102 | (0.3) | 1/683 | (0.1) | 2/893 | (0.2) |
| Type 2 | 4/1,102 | (0.4) | 3/683 | (0.4) | 3/893 | (0.3) |
| GDM | 59/1,102 | (5.4) | 38/683 | (5.6) | 64/893 | (7.2) |
| Others | 14/1,102 | (1.3) | 7/683 | (1.0) | 5/893 | (0.6) |
| No or not informed | 1022/1,102 | (92.7) | 634/683 | (92.8) | 819/893 | (91.7) |
| Hypertension | ||||||
| CAH | 52/1,102 | (4.7) | 37/683 | (5.4) | 55/893 | (6.2) |
| GH | 7/1,102 | (0.6) | 8/683 | (1.2) | 20/893 | (2.2) |
| Hypertensive peak | 1/1,102 | (0.1) | 0/683 | (0) | 0/893 | (0) |
| No or not informed | 1042/1,102 | (94.6) | 638/683 | (93.4) | 818/893 | (91.6) |
| Thyroid diseases | ||||||
| Gestational hypothyroidism | 22/1,102 | (2.0) | 14/683 | (2.0) | 15/893 | (1.7) |
| Previous hypothyroidism | 1/1,102 | (0.1) | 0/683 | (0) | 1/893 | (0.1) |
| Hypothyroidism | 96/1,102 | (8.7) | 66/683 | (9.7) | 80/893 | (9.0) |
| Hyperthyroidism | 3/1,102 | (0.3) | 1/683 | (0.1) | 1/893 | (0.1) |
| No or not informed | 980/1,102 | 88.9 | 602/683 | (88.1) | 796/893 | (89.1) |
| Consanguinity | ||||||
| Yes | 15/1,102 | (1.4) | 5/683 | (0.7) | 8/893 | (0.9) |
| No | 874/1,102 | (79.3) | 575/683 | (84.2) | 703/893 | (78.7) |
| Not informed | 213/1,102 | (19.3) | 103/683 | (15.1) | 182/893 | (20.4) |
| Familial or previous fetal abnormalities | ||||||
| Yes | 19/1,102 | (1.7) | 13/683 | (1.9) | 15/893 | (1.7) |
| No or not informed | 1083/1,102 | (98.3) | 670/683 | (98.1) | 878/893 | (98.3) |
| Type of delivery | ||||||
| Caesarean | 752/1,102 | (68.2) | 415/683 | (60.8) | 557/893 | (62.4) |
| Forceps | 3/1,102 | (0.3) | 0/683 | (0) | 2/893 | (0.2) |
| Vaginal | 321/1,102 | (29.1) | 248/683 | (36.3) | 318/893 | (35.6) |
| Not informed | 26/1,102 | (2.4) | 20/683 | (2.9) | 16/893 | (1.8) |
GDM = gestational diabetes mellitus; CAH = chronic arterial hypertension; GH = gestational hypertension; n/N = ratio between number of participants analyzed with complete outcome and the total number of participants in each trimester of pregnancy.