Table 1.
Characteristics of the Discovery Cohort, Replication Cohort I, and Replication Cohort II.
| Characteristic | Discovery Cohort (n= 8,082) |
Replication Cohort I (n=2,535) |
Replication Cohort II (n=587) |
|---|---|---|---|
| Maternal age in years, mean (SD) | 30.3 (7.5) | 32.9 (5.3) | 31.3 (3.6) |
| National background, n (%) Non-Dutch Dutch |
4,135 (51.2) 3,947 (48.8) |
Non-White: 1,493 (59.6) White: 1,042 (40.4) |
Non-Dutch: 80 (13) Dutch: 507 (82.3) |
| Education level, n (%) No education Primary education Secondary education Missing |
25 (0.3) 4,748 (58.7) 3,309 (41) - |
N/A* |
- 155 (26.4) 421 (71.7) 11 (1.9) |
| Monthly household income, n (%)** <€2,220/month >€2200/month Missing |
4,127 (51.1) 3,952 (48.9) - |
648 (25.6) 1,881 (74.2) 6 (0.2) |
33 (5.6) 542 (92.3) 12 (2.0) |
| Pre-pregnancy BMI (kg/m2), median (IQR) | 22.7 (4.7) | 25.4 (7.9) | 23.2 (4.4) |
| Parity, n (%) Nulliparity Multiparity Missing |
4,497 (55.6) 3,585 (44.4) - |
1,357 (53.5) 1,178 (46.5) - |
326 (55.5) 250 (42.6) 11 (1.9) |
| Maternal Psychopathology, median (IQR) | 0.17 (0.29) | N/A* | N/A* |
| Fetal sex, n (%) Male Female Missing |
4,092 (50.6) 3,988 (49.4) - |
1,130 (44.6) 1,142 (45.0) 263 (10.4) |
254 (43.3) 270 (46.0) 63 (10.7) |
| Birthweight in grams (median, IQR) | 3,430 (685) | 3,232 (629) | 3,450 (630) |
| Gestational age at birth in weeks, median (IQR) | 40.1 (1.9) | 39.1 (1.7) | 39.7 (1.7) |
| Maternal tobacco use, n (%) Never smoked during pregnancy Smoked until pregnancy was known Continued smoking in pregnancy Missing |
5,845 (72.3) 702 (8.7) 1,535 (19) - |
N/A* |
562 (95.7) - 12 (2.0) 13 (2.2) |
| Maternal alcohol use, n (%) Drank no alcohol during pregnancy Drank alcohol until pregnancy was known Drank occasionally during pregnancy Drank frequently during pregnancy (>1 glass/week in early pregnancy) Missing |
3,879 (48) 1,049 (13) 2,568 (31.8) 586 (7.2) - |
N/A* |
573 (97.6) - 1 (0.2) - 13 (2.2) |
| Maternal substance use, n (%) | 600 (7.4) | 19 (0.7) | N/A* |
| Season of 1st blood sample***, n (%) Winter Spring Summer Fall |
1,713 (28.2) 1,665 (27.4) 1,327 (21.9) 1,367 (22.5) |
578 (20.4) 1,036 (36.7) 599 (21.2) 608 (21.6) |
160 (35.4) 120 (26.5) 126 (27.9) 46 (10.2) |
| Season of 2nd blood sample***, n (%) Winter Spring Summer Fall |
1,798 (24.3) 2,142 (29) 1,754 (17.9) 1,702 (18.5) |
186 (23.8) 182 (23.3) 229 (29.3) 184 (23.6) |
131(34.2) 68 (17.8) 82 (21.4) 102 (26.6) |
| Infection score prior to first blood draw, n (%) 0 1 2 3 4 5 or higher |
2,151 (26.6) 2,306 (28.5) 1,252 (15.6) 592 (7.3) 175 (2.1) 32 (0.4) |
N/A* |
N/A* |
| Infection score prior to second blood draw, n (%) 0 1 2 3 4 5 or higher |
2,292 (28.4) 2,331 (28.8) 1,118 (13.8) 458 (5.7) 118 (1.5) 18 (0.2) |
N/A* |
N/A* |
| Twin pregnancy, n (%) | 88 (1.1) | 42 (1.7) | N/A* |
| Immune-related disease, n (%)**** | 650 (8.2) | N/A** | 41 (7.0) |
| Gestational age at sampling (weeks), median (min-max) | 19.2 (4.5-26.9) | 27.7 (3.7-42.1) | 20.2 (9.4-42.0) |
A total of 11,204 participants were included in the current study.
*N/A indicates that data was specific to the Discovery Cohort and was not measured or incomplete (>75% missing) in the replication cohorts.
**Monthly household income: For Replication Cohort I, numbers indicate insurance status: public (n=648) and private (n=1,881). For Replication Cohort II, numbers indicate employment status: unemployed (n=33) and paid job (n=552).
***Season: For the Discovery Cohort, season of first blood sample indicates the season of the sample collected at timepoint 1 in 6,062 participants. For Replication Cohort I, it indicates the season of the first blood sample that was collected (n=2,535). For Replication Cohort II, it indicates the season of the blood sample collected in trimester 1 (n=452). For the Discovery Cohort, season of second blood sample indicates the season of the sample collected at timepoint 2 (n=7,395). In Replication Cohort I, it indicates the season of the second blood sample that was collected (n=781). In Replication Cohort II, it indicates the season of the blood sample collected in trimester 2 (n=383).
****Immune-related disease include HIV, eczema, systemic lupus erythematosus (SLE), intestinal disorder, pre-gestation diabetes, multiple sclerosis, rheumatism.