Human foetal sacral length measurement for the assessment of foetal growthand development by ultrasonography and dissection

This study investigated the value of prenatal ultrasonographic measurements of sacrum as a predictor of in utero development and gestational age (GA), and to make a comparison between the data obtained by ultrasonography and dissection. A prospective cross-sectional study of ultrasonography was cond ucted in 186 pregnant women with uneventful single pregnancies. GA ranged f rom 14 to 40 weeks. and the relationships of sacrum length (SL) with GA, fe mur length (FL), biparietal diameter (BPD), head circumference (HC) and abd ominal circumference (AC) were evaluated. In addition, the sacral bones of 101 spontaneously aborted foetuses aged from 13 to 39 weeks were dissected and measured. The relationship of the results with GA was investigated. The re was a linear relationship between the ultrasonographic measurements of t he SL and the GA (R-2 = 0.93, P < 0.001), the FL (R-2 = 0.93, P < 0.001), t he BPD (R-2 = 0.93, P < 0.001), the HC (R-2 = 0.92, P < 0.001) and the AC ( R-2 = 0.90, P < 0.001). The rate of increase of SL was significantly higher before 28 weeks of gestation than in later pregnancy, with a correlation c oefficient between SL and GA of 0.96 and 0.88, respectively. The SL measure ments obtained by dissection were similar to those of ultrasonography. Ther e was a linear relationship between the SL and the GA (R-2 = 0.96, P < 0.00 1) and the correlation coefficients between SL and GA were 0.97 before 28 w eeks of gestation, and 0.94 in later weeks. In conclusion, this study demon strates a high correlation between the SL, GA and other standard measuremen ts of foetal growth, and suggests that SL measurement is a valuable predict or of GA in the foetuses with normal growth.