Table 1: Characteristics of the study population (median and range).

First trimester
( )
Second trimester
( )
Third trimester
( )

Gestational age in wks, median (range)12+6 (11+6–13+6)22+0 (20+0–22+4)32+1 (31+6–33+5)
Maternal age in yrs, median (range)29 (17–36)28 (16–38)29 (17–39)
Maternal weight in Kg on date of sampling, median (range)68.4 (54.0–89.0)69.0 (42.9–104.0)76.0 (46.9–112.0)
BMI in Kg/m2 on date of sampling, median (range)24.2 (18.0–32.7)25.3 (17.1–36)29.0 (17.4–42.3)
BMI in Kg/m2 at booking, median (range)24.2 (18.0–32.7)24.1 (17–34.9)24.8 (13.5–40)
Racial origin
 Caucasian, (%)25 (58.1)25 (54.3)25 (56.8)
 Afro-Caribbean, (%)18 (41.9)21 (45.7)19 (43.2)