Ultrasonographically adjusted midtrimester risk of trisomy 21 and significant chromosomal defects in advanced maternal age

• Published in: American journal of obstetrics and gynecology 1996-12, Vol.175 (6), p.1563-1568
• Main Authors: Bahado-Singh, Ray O., Deren, Özgür, Tan, Ann, D'Ancona, Roberto Levi, Hunter, David, Copel, J.A., Mahoney, M.J.
• Format: Article
• Language: English
• Subjects: advanced maternal age; Biological and medical sciences; Biometry; Chromosome Aberrations; Chromosome Disorders; Down Syndrome; Female; Gynecology. Andrology. Obstetrics; Humans; Management. Prenatal diagnosis; Maternal Age; Medical sciences; Pregnancy; Pregnancy Trimester, Second; Pregnancy, High-Risk; Pregnancy. Fetus. Placenta; Risk Factors; Ultrasonography, Prenatal
• ISSN: 0002-9378; 1097-6868
• DOI: 10.1016/S0002-9378(96)70107-2

OBJECTIVE: Our purpose was to determine whether normal midtrimester ultrasonography results reduces the risk of fetal Down syndrome and any clinically significant chromosomal defects in pregnancies with advanced maternal age and to develop risk tables on the basis of age and ultrasonographic results. STUDY DESIGN: Biometry data were obtained in 4079 women between 15 and 24 weeks undergoing amniocentesis for maternal age. Expected values of humerus, femur, both combined, and abdominal circumference based on biparietal diameter were generated from a normal group. Observed/expected values of each parameter and nuchal thickness ≥6 mm was used to screen for Down syndrome and any clinically significant chromosome defects. Receiver-operator characteristic curves were used to determine threshold screening values for each parameter. By use of stepwise logistic regression the optimal measurements for detection of chromosome anomalies were established. An abnormal ultrasonography result was defined as either abnormal biometry choroid plexus cysts or a structural defect. RESULTS: The finding of shortened humerus (observed/expected