title: Prenatal screening for Down syndrome and neural tube defects in twin pregnancies.
abstract: Prenatal screening and diagnosis in a twin pregnancy is not straightforward. Once a twin pregnancy has been identified, women and their partners need time to consider the implications and decide whether they wish the pregnancy to be screened for Down syndrome or neural tube defects. We discuss here how multiple marker screening for Down syndrome and alpha-fetoprotein screening for neural tube defects can be carried out, given that this is the parents' chosen option and that the health professionals involved are capable of performing a diagnosis and selective feticide, should this arise.
authors.affiliation: Wolfson Institute of Preventive Medicine, Barts and the Royal London School of Medicine and Dentistry, London, UK. n.j.wald@qmul.ac.uk
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Wald
authors.forename: Simon
authors.initials: S
authors.lastname: Rish
mesh_terms: D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D009333:Neck / Q000000981:diagnostic imaging / Q000196:embryology; D009436:Neural Tube Defects / Q000097:blood / Q000175:diagnosis*; D011247:Pregnancy; D011264:Pregnancy Trimesters; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism; D011296:Prenatal Diagnosis; D014427:Twins; D016216:Ultrasonography, Prenatal
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A