Prenatal ultrasound findings in affected and unaffected pregnancies that are screen-positive for trisomy 18: the California experience

• Published in: Prenatal diagnosis 2000-04, Vol.20 (4), p.293-299
• Main Authors: Feuchtbaum, Lisa B., Currier, Robert J., Lorey, Fred W., Cunningham, George C.
• Format: Article
• Language: English
• Subjects: alpha-Fetoproteins - analysis; Biological and medical sciences; California; Chorionic Gonadotropin - blood; Chromosomes, Human, Pair 18; Estriol - blood; Female; Gestational Age; Gynecology. Andrology. Obstetrics; Humans; Karyotyping; Management. Prenatal diagnosis; Medical sciences; Pregnancy; Pregnancy. Fetus. Placenta; prenatal diagnosis; Trisomy; trisomy 18; Ultrasonography, Prenatal; ultrasound abnormalities
• ISSN: 0197-3851; 1097-0223
• DOI: 10.1002/(SICI)1097-0223(200004)20:4<293::AID-PD801>3.0.CO;2-O

This study investigated whether significant differences in ultrasound findings exist between trisomy 18 affected and unaffected pregnancies positive by serum screening. Ultrasound reports were reviewed for 335 screen‐positive women. This represented 65% of all trisomy 18 screen‐positive patients who had follow‐up services at any of 117 Californian state‐approved Prenatal Diagnosis Centers during a six‐month period from November 1, 1995 to April 30, 1996. Ultrasound reports were available for 100% of trisomy 18 fetuses diagnosed during the six month period (n=23). Ultrasound findings were reported as normal in 35% of the fetuses affected with trisomy 18. The number and type of abnormalities observed in the affected and unaffected groups are described. When compared to unaffected cases, the trisomy 18 affected fetuses had a greater re‐dating discrepancy on follow‐up ultrasound evaluation and significantly lower femur length to biparietal diameter (FL/BPD) ratio measurements. We recommend that all women who are screen positive for trisomy 18 be encouraged to have amniocentesis, regardless of ultrasound findings, since affected fetuses may not be detected otherwise. Copyright © 2000 John Wiley & Sons, Ltd.