title: Antenatal screening - the first and second trimester.
abstract: Antenatal screening is performed in the first or second trimester to determine whether a pregnant woman's baby has an increased risk of having Down syndrome (a chromosomal abnormality affecting one in 500 pregnancies), Edward syndrome (one in 3000) or open neural tube defects (one in 750). First trimester screening combines results from a blood test with a nuchal translucency and nasal bone obstetric scan during the first trimester of pregnancy. Second trimester screening requires only a blood test. The screening approach varies across Australia; this article primarily describes the Victorian protocol.
authors: Maternal Serum Screening Laboratory, VCGS Pathology, Murdoch Childrens Research Institute, Royal Childrens Hospital, Parkville, Victoria. leonard.bonacquisto@ghsv.org.au
authors: Leonard
authors: L
authors: Bonacquisto
mesh_terms: D002887:Chromosomes, Human, Pair 18; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008403:Mass Screening; D009436:Neural Tube Defects / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D018570:Risk Assessment; D014314:Trisomy / Q000175:diagnosis*; D016216:Ultrasonography, Prenatal; D014739:Victoria