title: The influence of parity and gravidity on first trimester markers of chromosomal abnormality.
abstract: We have studied changes in first trimester fetal nuchal translucency (NT) and maternal serum free beta-hCG and PAPP-A with gravidity and parity in 3252 singleton pregnancies unaffected by chromosomal abnormality or major pregnancy complications. We have shown that gravidity and parity is associated with a small but progressive decrease in fetal NT and a small but progressive increase in free beta-hCG and PAPP-A. None of these small changes with increasing gravidity or parity are statistically significant and hence correction for these variables is not necessary when considering first trimester screening for chromosomal abnormalities.
authors.affiliation: Endocrine Unit, Clinical Biochemistry Department, Harold Wood Hospital, Gubbins Lane, Romford, Essex RM3 0BE, UK. Kevin_Spencer@Compuserve.com
authors.forename: K
authors.initials: K
authors.lastname: Spencer
authors.forename: C Y
authors.initials: CY
authors.lastname: Ong
authors.forename: A W
authors.initials: AW
authors.lastname: Liao
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D004314:Down Syndrome / Q000175:diagnosis*; D005260:Female; D020073:Gravidity; D006801:Humans; D008403:Mass Screening / Q000379:methods / Q000592:standards; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism*; D011296:Prenatal Diagnosis; D016216:Ultrasonography, Prenatal
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A