Table 1 Main characteristics of the study population (n = 447)
Maternal characteristics | Median (range) or n (%) |
|---|---|
Age (years) | 32.8 (19.5–46.6) |
Weight (kg) | 63 (40–173) |
Multiparous | 266 (59.5%) |
Ethnicity | |
 Caucasian | 394 (88.1%) |
 Other | 53 (11.9%) |
Amp induced pregnancy | 25 (5.6%) |
Auto-immune disease | 24 (5.4%) |
Anticoagulant treatment | 9 (2.0%) |
Gestational age (wg) | 15.2 (11.4–34.1) |
Fetal fraction (%) | 11.0 (1.0–31.8) |