Subtle ultrasonographic anomalies: Do they improve the Down syndrome detection rate?

• Published in: American journal of obstetrics and gynecology 1998-03, Vol.178 (3), p.441-445
• Main Authors: Deren, Ozgur, Mahoney, Maurice J., Copel, Joshua A., Bahado-Singh, Ray O.
• Format: Article
• Language: English
• Subjects: Abnormalities, Multiple - diagnostic imaging; Anthropometry - methods; Biological and medical sciences; Cerebral Ventricles - abnormalities; Cerebral Ventricles - diagnostic imaging; Down syndrome; Down Syndrome - diagnostic imaging; Female; Fingers - abnormalities; Fingers - diagnostic imaging; Gynecology. Andrology. Obstetrics; Humans; Intestines - abnormalities; Intestines - diagnostic imaging; Kidney Pelvis - abnormalities; Kidney Pelvis - diagnostic imaging; Management. Prenatal diagnosis; Medical sciences; Predictive Value of Tests; Pregnancy; Pregnancy Trimester, Second; Pregnancy. Fetus. Placenta; Prospective Studies; Statistics as Topic; Ultrasonographic biometry; Ultrasonography, Doppler, Color; Ultrasonography, Doppler, Transcranial; Ultrasonography, Prenatal
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1016/S0002-9378(98)70417-X

OBJECTIVE: Our purpose was to determine whether the identification of subtle anomalies further improves Down syndrome detection over standard ultrasonographic biometry and the detection of gross morphologic defects. STUDY DESIGN: The screening efficiency of clinodactyly, dilated renal pelvis (≥4 mm), echogenic bowel, mild ventriculomegaly (≥10 to 15 mm), and two-vessel cord was determined prospectively in midtrimester fetuses at amniocentesis. The screening efficiency of increased nuchal thickness and shortened long-bone length (standard biometry) and gross morphologic defects was determined for comparison. Multiple backward stepwise regression analysis was used to determine which subtle anomalies significantly correlated with Down syndrome detection rate and whether they increased Down syndrome detection over that with standard biometry and morphologic defects. RESULTS: Although all subtle anomalies except two-vessel cord correlated with the presence of Down syndrome on univariate analysis, only echogenic bowel (Wald χ 2 = 15.0211, p = 0.0001) and clinodactyly (Wald χ 2 = 9.4273, p = 0.002) persisted in regression analysis of the subtle anomaly group. When either of the above-described anomalies was present, the detection rate for Down syndrome was 28.6%, p < 0.00001. For the combination of standard biometry (either increased nuchal thickness or short humerus) or gross anatomic defect, Down syndrome detection rate was 53.3% ( p < 0.00000001). This increased to 63.2% ( p < 0.00000001) when subtle anatomic defects (either echogenic bowel or clinodactyly) were included in the definition of an abnormal sonogram. CONCLUSION: Subtle anomalies, of which echogenic bowel and clinodactyly are the most significant, further increase Down syndrome screening efficiency over standard biometry or the finding of gross anatomic defect. Our data appear to support the addition of subtle anomaly findings to ultrasonographic screening for Down syndrome. (Am J Obstet Gynecol 1998;178:441-5.)