Sonographic markers of aneuploidies at 6-10 weeks of gestation

Objectives: To determine if sonographic features of live embryos at 6-10 weeks' gestation are altered in aneuploidies. Methods: Embryonic crown rump length (CRL). embryonic heart rate. gestational sac diameter (GSD) and yolk sac diameter (YSD) were measured by transvaginal sonography in 5603 live embryos from singleton pregnancies at 6-10 weeks' gestation. The measurements were expressed as differences from the expected normal mean for CRL (delta values) and median delta values in the aneuploid cases were compared to the euploid group. Results: 5393 pregnancies resulted in the live birth of phenotypically normal neonates and these cases constituted the euploid group. In 55 cases there was subsequent prenatal diagnosis of aneuploidies (trisomy 21. n = 28; trisomy 18, n = 10; trisomy 13, n = 10; triploidy. n = 4; Turner syndrome, n = 3). The median and interquartile range (IQR) of delta embryonic heart rate in trisomy 18 was -19.44 (-23.77 to -7.20) bpm and in trisomy 13 it was 11.12 (7.25 to 20.39)bpm, which were significantly lower and higher, respectively, than in euploid embryos (median -0.05, IQR -6.18 10 6.21 bpm). The median delta YSD in trisomy 21 was higher than in euploid fetuses (median 0.56, IQR 0.23 to 0.79 and median -0.17, IQR -3.11 to 2.82 mm). There were no other significant differences in measurements between the groups. Conclusion: At 6-10 weeks' gestation there are sonographically detectable differences between euploid and trisomic embryos. (c) 2011 Elsevier Ireland Ltd. All rights reserved.