title: Secretory component of immunoglobulin A in maternal serum and the prediction of preterm delivery.
abstract: OBJECTIVE
  Our purpose was to determine whether the secretory component of immunoglobulin A in maternal serum predicts delivery before 34 weeks' gestation.
  
  
  METHODS
  Primigravid women of an urban population in New Zealand were recruited at booking into a prospective longitudinal nested case control study (n = 1651; after exclusions and withdrawals, n = 1511). Serum was collected at 8 to 12 weeks, 15 to 18 weeks, 21 to 24 weeks, 28 to 30 weeks, and 36 to 38 weeks of gestation and 6 weeks post partum. Concentrations of the secretory component of immunoglobulin A were determined by enzyme-linked immunosorbent assay in all women who were delivered preterm (n = 53) and in controls randomly selected from women delivered at > or =37 weeks' gestation (n = 178).
  
  
  RESULTS
  Serum concentrations of the secretory component of immunoglobulin A were similar in women delivered at term or preterm throughout pregnancy (n = 21 delivered at <34 weeks and n = 32 at 34 to 36.9 weeks, incidence 3.5%). Receiver-operator characteristic curves showed no discriminating ability of the secretory component of immunoglobulin A. Smokers had 50% higher concentrations than nonsmokers did (p < 0.0001 by analysis of variance).
  
  
  CONCLUSIONS
  The secretory component of immunoglobulin A in maternal serum does not predict preterm delivery in a low-risk population.
authors.affiliation: Research Centre in Reproductive Medicine, Department of Obstetrics and Gynaecology, National Women's Hospital, Auckland, New Zealand.
authors.forename: J C
authors.initials: JC
authors.lastname: Schellenberg
authors.forename: R A
authors.initials: RA
authors.lastname: North
authors.forename: R
authors.initials: R
authors.lastname: Taylor
authors.forename: R L
authors.initials: RL
authors.lastname: Zhou
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000097:blood*; D007234:Infant, Premature; D008137:Longitudinal Studies; D007752:Obstetric Labor, Premature / Q000097:blood / Q000175:diagnosis*; D011247:Pregnancy / Q000097:blood*; D011256:Pregnancy Outcome; D011446:Prospective Studies; D012372:ROC Curve; D012907:Smoking / Q000097:blood
chemical_list: D007071:Immunoglobulin A, Secretory