The recurrence of sonographic ‘soft markers’: ominous sign or ‘just’ genetics?

Objectives: ‘Soft markers’ (SMs) are nonspecific findings that might convey a higher risk for Down syndrome. We sought to determine the recurrence rate of the most common SM in subsequent pregnancies. Methods: This is a retrospective study of all women who underwent early or late fetal sonographic anatomical screening in our ultrasound unit. The examined SMs were pyelectasis, thickened nuchal fold (TNF) and echogenic intracardiac foci (EIF). Data on recurrence and pregnancy outcome were retrieved retrospectively. Results: The database included 20 672 singleton pregnancies; SMs were detected in 2347 (11.1%) of the fetuses and were isolated in 1739 (74%). Rates of solitary findings in the pregnancies were 6.5% (1360/20 672) EIF, 3% (624/18 850) TNF and 1.7% (363/20 672) pyelectasis. The recurrence rate of EIF, TNF and pyelectasis in subsequent consecutive pregnancies was 21%, 27% and 16%, respectively. Overall, 62 cases of Down syndrome were diagnosed in (1 : 333 pregnancies). No cases were diagnosed in patients with recurrent SMs. Conclusion: The high recurrence rate of solitary SM implies for genetic predisposition. These results might improve our counseling for pregnant women affected by the reappearance of solitary SM. Further studies are needed to assess the likelihood ratio for SM if recurrence occurs.