Evaluation of the usefulness of the fetal femur length and humeral length to detect Down syndrome in Korean subjects / 대한산부인과학회지

ABSTRACT

OBJECTIVE: We investigated the usefulness of shortening of the fetal femur length (FL) and humeral length (HL) to predict Down syndrome at the middle gestation of pregnancy in Korean subjects. METHODS: This retrospective study involved 41 fetuses with Down syndrome and 328 fetuses with normal chromosome between 14+0 and 28+6 weeks of gestation. The expected FL and HL for any biparietal diameter (BPD) was calculated based on the control group data. The odds ratios for measure to expected FL and HL in comparison between normal fetuses and Down syndrome fetuses were calculated. The sensitivities of short FL and HL to predict Down syndrome were analyzed at a fixed false positive rate of 5%. RESULTS: The lengths of femur and humerus long bone for any BPD in Down syndrome group were significantly shorter than the lengths in control group (P<0.001). A low ratio of measured to expected FL and HL increased the risk of fetal Down syndrome (P<0.001). At a fixed false positive rate of 5%, the sensitivities were 21.3% (95% confidence interval [CI] 0.698~0.852, P<0.001) in FL and 29.9% (95% CI 0.773~0.914, P<0.001) in HL. CONCLUSION: Both of short FL and HL are poor marker for Down syndrome at the middle gestation of pregnancy in Korean population though the sensitivity of HL was higher than FL.