Dubowitz assessment of gestational age and agreement with prenatal methods

We compared assessment of gestational age by Dubowitz score with ultrasonic measurement of the biparietal diameter (BPD), and then evaluated how infants were classified by these methods as small-for-gestational age (SGA), and as pre- or post-term births. BPD gestational age was assessed at week 17 to 20 of pregnancy while the Dubowitz scoring was done at birth. "Limits of agreement" between methods and kappa values were calculated and used to evaluate agreement. Among 839 included infants, there was moderate agreement between Dubowitz score and BPD (limits of agreement; -2.3; +2.1 weeks; weighted kappa: 0.46) in the assessment of gestational age. Agreement between Dubowitz score and BPD in the classification of SGA (kappa: 0.75, 95% confidence interval [CI]: 0.69-0.81) and preterm infants (kappa: 0.68, 95% CI: 0.56-0.80) was good, whereas agreement on infants born post-term was no better than chance (kappa: 0.14, 95% CI: -0.02(-)+0.30). We conclude that despite moderate agreement between Dubowitz score and BPD in the assessment of gestational age, agreement in the classification of low-birth-weight infants as SGA and as premature births was good.