Table 1.
Descriptive statistics of mother and child pairs
| Characteristics | Value |
|---|---|
| hCG, median (95 % range), IU/l, | 35559.0 (6106.8–101808.5) |
| Birth weight, mean (SD), g | 3412.0 (559.7) |
| Gestational age at blood sampling, median (95 % range), weeks | 14.4 (10.1–26.2) |
| Gestational age at birth, mean (SD), weeks | 39.8 (1.9) |
| Age, mean (SD), years | 29.6 (5.3) |
| BMI, median (95 % range), kg/m2 | 23.9 (18.7–36.5) |
| Parity, n (%) | |
| Nullipara | 4531 (55.3) |
| Primipara | 2475 (30.2) |
| Multipara | 1187 (14.5) |
| Smoking status, n (%) | |
| Non smokers | 5953 (72.7) |
| Stopped smokers | 691 (8.4) |
| Smokers | 1549 (18.9) |
| Educational level, n (%) | |
| No education or primary education | 1046 (12.8) |
| Secondary education | 3844 (46.9) |
| Higher education | 3303 (40.3) |
| Ethnicity, n (%) | |
| Dutch | 3742 (46.6) |
| Moroccan | 530 (6.6) |
| Turkish | 710 (8.8) |
| Surinam | 686 (8.5) |
| Other-European | 598 (7.5) |
| Other-Non-European | 1758 (21.9) |
| Fetal sex, n (%) | |
| Male | 4124 (50.3) |
| Female | 4069 (49.7) |
| Gestational weight gain, mean (sd), kg | 10.0 (5.1) |
| Placental weight at birth (g), median, (95 % range) | 620.0 (390.0–950.0) |