Reference interval for fetal biometry in Italian population.

OBJECTIVES To validate new references charts and equations for fetal biometry in an Italian unselected population. METHODS A cross-sectional study involving 4896 women with singleton viable pregnancies, at Artemisia Fetal Maternal Medical Centre between May 2009 and December 2009. Each woman was scanned only once, between 14+0 and 40+0 weeks of gestation. The fetal standard biometric measurements were recorded. For each parameter, regression models were fitted to estimate the percentile at each gestational age. In order to be compared to other reference equations, the fetal biometric measurements at each gestational age were expressed as Z-scores. RESULTS New fetal charts and references equations for Italian population were developed according to the recommend multistep statistical procedure. CONCLUSION To our knowledge this is the first Italian study with the largest sample size ever reported in the literature. In addiction, our newer charts of reference centiles for fetal biometric measurements are useful in the obstetrical clinical practice for the Italian population.