title: Why confine chorionic villus (placental) biopsy to the first trimester?
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
authors.forename: P W
authors.initials: PW
authors.lastname: Soothill
authors.forename: C H
authors.initials: CH
authors.lastname: Rodeck
authors.forename: R C
authors.initials: RC
authors.lastname: Warren
authors.forename: C M
authors.initials: CM
authors.lastname: Gosden
mesh_terms: D001706:Biopsy / Q000379:methods; D002824:Chorionic Villi / Q000032:analysis; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis; D006801:Humans; D007621:Karyotyping; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011296:Prenatal Diagnosis / Q000379:methods*; D013997:Time Factors