Prenatal diagnosis of trisomy 21
Massé, J.; Forest, J.C.
Annales de Biologie Clinique 48(8): 536-540
1990
ISSN/ISBN: 0003-3898 PMID: 1705107 Document Number: 348369
Trisomy 21 is the most frequent chromosome anomaly found in the living newborns. Prenatal diagnosis by amniocentesis was limited until recently to older pregnant women. Maternal blood biochemical markers (alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin) and ultrasonographic signs (nuchal fold thickening, femur length to biparietal diameter ratio) can discriminate a group of higher-risk women even though they are not aged. Numerous factors need to be considered when establishing such a screening program including pre-analytical variables (gestational age, diabetes, smoking, race), analytical variables (choice of reagents, quality control) or post-analytical (result reporting, follow-up of abnormal results). Until now the study of these markers has been restricted to the second trimester but they could become useful earlier during pregnancy.