Prognostic value of ultrasound findings of fetal cystic hygroma detected in early pregnancy by transvaginal sonography

Objective To assess the prognostic value of first and early second trimester transvaginal ultrasound findings of fetal cystic hygroma such as volume, presence of septa and associated fetal anomalies or malformations. Design A prospective study of fetal cystic hygroma volume detected at 10–15 weeks of gestation by transvaginal scan. Subjects The study comprised a series of 33 cystic hygromas detected throughout the period March 1994 to March 1998 in 1918 pregnant women. Methods The volume of the hygroma and the presence of septa and other associated fetal anomalies or malformations were evaluated and correlated with fetal karyotype, persistence of the hygroma and pregnancy outcome. Results A volume equal to or greater than 75 mm 3 revealed a sensitivity of 66.7% [eight of 12 cases; 95% confidence interval (CI), 34.9–90.1%] for the identification of abnormal fetal karyotype, 72.7% (eight of 11 cases; 95% CI, 39.0–90.4%) for the identification of persistence of the hygroma and 90% (nine of 10 cases; 95% CI, 55.5–99.7%) for identification of an unfavorable outcome of pregnancy. Furthermore, the prognostic value of ultrasound in determining pregnancy and fetal outcome were improved by combining data on the volume of the hygroma and the presence of associated anomalies or malformations. Conclusions Measuring the volume of a cystic hygroma proves to be a useful ultrasound prognostic indicator in determining the risk of an associated karyotypic abnormality and adverse fetal and pregnancy outcome. However, due to limited sample size, caution is required in interpretation of the data and further studies are needed. Copyright © 2000 International Society of Ultrasound in Obstetrics and Gynecology