Assessment of gestation by ultrasound in various stages of pregnancy in infants differing in size and ethnic origin.

A clinical assessment of gestational age after birth has been compared with the ultrasound measurement in utero at various stages of pregnancy in a population of mixed socio-economic status and racial origin. In infants who were small-for-dates or large-for-dates at birth, accurate prediction from ultrasound measurement could only be achieved if the crown rump length or the biparietal diameter was measured before 20 weeks gestation. At this time, the infants destined to be small-for-dates or large-for-dates at birth show no growth retardation or acceleration. There is also no influence of racial origin on the measurements.