title: First-trimester fetal karyotyping by direct method. Technical and diagnostic problems.
mesh_terms: D002824:Chorionic Villi / Q000648:ultrastructure*; D002869:Chromosome Aberrations; D002871:Chromosome Banding; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007621:Karyotyping / Q000379:methods*; D008677:Metaphase; D008938:Mitosis; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011296:Prenatal Diagnosis / Q000379:methods*