title: First-trimester genetic diagnosis in multiple pregnancy: principles and potential pitfalls.
abstract: Both the principles of first-trimester genetic diagnosis in multiple pregnancy and the special considerations required to avoid potential diagnostic pitfalls are presented. The experience consisted of 65 cases of twins and one case of quadruplets. Dichorionic twins were recognized by sonography in 54 cases. Transabdominal aspiration was generally preferred to transcervical for obtaining chorionic tissue, although in two cases both approaches were used. Diagnostic error following erroneous sampling was reported in 3 out of 54 sets of dichorionic twins (5.5 per cent). When like-sex dichorionic twins cannot be differentiated by cytogenetic or DNA polymorphism studies, amniocentesis should be recommended to confirm the reliability of the result on chorionic tissue.
authors.affiliation: First Clinic of Obstetrics and Gynaecology, University of Milan, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Brambati
authors.forename: L
authors.initials: L
authors.lastname: Tului
authors.forename: A
authors.initials: A
authors.lastname: Lanzani
authors.forename: G
authors.initials: G
authors.lastname: Simoni
authors.forename: M
authors.initials: M
authors.lastname: Travi
mesh_terms: D000328:Adult; D015193:Chorionic Villi Sampling / Q000379:methods*; D002869:Chromosome Aberrations / Q000175:diagnosis* / Q000000981:diagnostic imaging; D025063:Chromosome Disorders; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011272:Pregnancy, Multiple; D011783:Quadruplets; D015203:Reproducibility of Results; D014427:Twins; D014463:Ultrasonography