title: First-trimester prediction of birth weight.
abstract: OBJECTIVE
  To determine whether the parameters used in first-trimester screening for aneuploidies contribute significantly to the prediction of birth weight.
  
  
  METHODS
  In this retrospective cohort study (n = 4110), nuchal translucency (NT), free β-chorionic gonadotropin (fβ-hCG), and pregnancy-associated plasma protein-A (PAPP-A) blood concentrations were measured between 11 + 0 and 13 + 6 weeks. Multiple pregnancies, chromosomal anomalies, major fetal defects, and deliveries before 24 weeks were excluded.
  
  
  RESULTS
  NT (0.95 versus 0.98 multiples of the expected median [MoM], p < 0.001) and PAPP-A (0.93 versus 1.06 MoM, p = 0.005) were significantly lower in small-for-gestational-age (SGA) newborns (<10th percentile) than the unaffected group, but not fβ-hCG (0.89 versus 0.93 MoM, p = 0.113). NT was significantly higher (1.03 versus 0.98 MoM, p < 0.001) in the large-for-gestational-age (LGA) group (>90th percentile) compared with the unaffected group, and biomarkers did not differ. After controlling for gestational age, maternal weight, smoking status, ethnicity, and fetal sex, first-trimester markers contributed to the prediction of birth weight in a multiple linear model but did not significantly improved the prediction of SGA and LGA compared with maternal characteristics alone.
  
  
  CONCLUSIONS
  Parameters used in first-trimester screening for aneuploidies contribute to the prediction of birth weight but their clinical utility to detect women at risk of SGA or LGA baby is limited.
authors.affiliation: Department of Obstetrics and Gynecology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, Quebec, Canada. isabelle@boucoiran.fr
authors.forename: Isabelle
authors.initials: I
authors.lastname: Boucoiran
authors.forename: Anissa
authors.initials: A
authors.lastname: Djemli
authors.forename: Catherine
authors.initials: C
authors.lastname: Taillefer
authors.forename: Françoise
authors.initials: F
authors.lastname: Rypens
authors.forename: Edgard
authors.initials: E
authors.lastname: Delvin
authors.forename: François
authors.initials: F
authors.lastname: Audibert
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D001724:Birth Weight; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D015331:Cohort Studies; D004314:Down Syndrome / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000235:genetics; D005260:Female; D005820:Genetic Testing; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D016014:Linear Models; D008297:Male; D048208:Nuchal Translucency Measurement; D011237:Predictive Value of Tests; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000097:blood* / Q000235:genetics; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D012189:Retrospective Studies
chemical_list: D015415:Biomarkers; D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A