Mid-trimester ultrasound prediction of gestational age: advantages and systematic errors
Objective To detect possible sources of bias in ultrasound prediction of gestational age. Subjects and Methods Using the Swedish Medical Birth Registry, 571 617 women were identified who were delivered between 1990 and 1997 and who had obtainable information on last menstrual period and expected date of delivery according to ultrasound. Results Male fetuses were more likely than females to be judg
