ABSTRACT
Gestational age determination based on obstetric dating criteria, early pregnancy
ultrasound scans, Dubowitz examinations, and ultrasound scans performed shortly before
delivery were reviewed for 69 preterm infants requiring neonatal intensive care. The
last ultrasound scans underestimated gestational age by a median of 8 days, and by
2 weeks or more in 20 of the 69 cases, as opposed to best dating criteria. Ultrasonic
fetal weight estimation was more accurate, but erred by more than 20% in 10% of cases.
When obstetric decisions regarding preterm neonates must be made without prior information
regarding gestational age, late ultrasound findings must be applied with extreme care.
