Anthropometric charts for infants with trisomies 21, 18, or 13 born between 22 weeks gestation and term: the VON charts.

Data on birth weight for gestational age (GA) are not well described for infants with trisomy 21 (T21), trisomy 18 (T18), or trisomy 13 (T13). We report on anthropometric charts of infants with these conditions using data from the Vermont Oxford Network (VON). Data from a total of 5,147 infants with T21 aged 22-41 weeks, 1,053 infants with T18 aged 22-41 weeks, and 613 infants with T13 aged 22-40 weeks were used to create birth weight for GA charts. Head circumference for GA charts were created for infants with T21 only. Combined-sex charts were generated for infants with T18 or T13 while sex-specific charts were generated for infants with T21. Smoothed centiles were created using LmsChartMaker Pro 2.3. Among the three examined groups, infants with T18 were the most likely to be growth restricted while infants with T21 were the least likely to be growth restricted. The new charts for infants with T21 were also compared to the Lubchenco and Fenton charts and both show frequent misclassification of infants with T21 as small or large for GA. The new charts should prove to be useful, especially for infants with T21, to assist in medical management and guide nutrition care decisions.