| The aim of present dissertation was to determine whether iliac wing angle measurement in first and second trimester fetuses is a useful sonographic marker for the detection of trisomy 21, 18 and 13.;Fetal iliac angle measurements were performed in 1928 first and second trimester fetuses at the Semmelweis University, I. Department of Obstetrics and Gynecology, between 1999 and 2004. The measurement was taken from a transverse section of the fetal pelvis, which was photo documented during each examination. The iliac angle measurements in fetuses with trisomy 21 (n=50), trisomy 18 (n=16) and trisomy 13 (n=11) were compared with iliac angle measurement in fetuses with normal karyotypes (n=1754). The sensitivity, specificity, positive predictive value, negative predictive value and false positive ration in trisomy 21 fetuses compared for multiple cutoff value. Statistical significance for measurements was estimated for trisomy 21,18 and 13, gestational age, fetal sex, and interobserver reproducibility.;In the normal fetuses the mean (+/- standard deviation [SD]) iliac wing angle was 63,99° (+/-SD 14,25; with a range from 24,10° to 108,00°). The mean iliac wing angle in the fetuses with trisomy 21 was 90,71° (+/-SD 14,50; with a range from 50,50° to 118,00°); 73,46° (+/-SD 25,11 with a range from 46,70° to 158,00°) and 75,64° (+/-SD 16,56 with a range from 51,00° to 105,50°) in fetuses with trisomy 18 and 13. These values detected in fetuses with trisomy 21 were significantly higher than those seen in normal fetuses. There was no significant difference between the iliac angle measured in fetuses with trisomy 18 and 13 and healthy fetuses.;The proven larger iliac wing angle in neonates with Down-syndrome can be demonstrated sonographically during the pregnancy, especially during the second trimester, and may be useful in prenatal screening of trisomy 21. The first time when the measurement is possible is 11th week of gestation. Fetal sex or gestational age did not have a statistically significant influence on iliac angle value.;The sonographic measurement of the fetal iliac angle can not be used as a marker for trisomy 18 and 13, fetuses in question, on average, have iliac angles only a few degrees larger than healthy fetuses. |
