title: Maternal serum polychlorinated biphenyl concentrations across critical windows of human development.
abstract: BACKGROUND
  Few data are available on polychlorinated biphenyl (PCB) concentrations over critical windows of human reproduction and development inclusive of the periconception window.
  
  
  OBJECTIVE
  Our goal was to measure changes in PCB concentrations from preconception to pregnancy, through pregnancy, or after a year without becoming pregnant.
  
  
  METHODS
  Seventy-nine women planning pregnancies were prospectively enrolled and followed for up to 12 menstrual cycles of attempting pregnancy. Blood specimens were obtained from participating women preconceptionally (n = 79), after a positive pregnancy test leading to a live birth (n = 54) or pregnancy loss (n = 10), at approximately 6 weeks postpartum (n = 53), and after 12 unsuccessful cycles (n = 9) for toxicologic analysis of 76 PCB congeners. We estimated overall and daily rate of change in PCB concentration (nanograms per gram serum) adjusting for relevant covariates, serum lipids, and baseline PCB concentration.
  
  
  RESULTS
  Significant (p < 0.0001) decreases in the mean overall and daily rate of change in PCB concentrations were observed between the preconception and first pregnancy samples for total (-1.012 and -0.034, respectively), estrogenic (-0.444 and -0.016, respectively), and antiestrogenic (-0.106 and -0.004, respectively) PCBs among women with live births. Similar significant decreases in total (-1.452 and -0.085), estrogenic (-0.647 and -0.040), and antiestrogenic (-0.093 and -0.004) PCB concentrations were seen for women with pregnancy losses. No significant changes were observed for PCB congener 153.
  
  
  CONCLUSIONS
  These data suggest that PCB concentrations may change during the periconception interval, questioning the stability of persistent compounds during this critical window.
authors.affiliation: Epidemiology Branch, Division of Epidemiology, Statistics and Prevention Research, National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Bloom
authors.forename: Germaine M
authors.initials: GM
authors.lastname: Buck Louis
authors.forename: Enrique F
authors.initials: EF
authors.lastname: Schisterman
authors.forename: Aiyi
authors.initials: A
authors.lastname: Liu
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Kostyniak
mesh_terms: D000328:Adult; D002657:Child Development; D047108:Embryonic Development; D004785:Environmental Pollutants / Q000097:blood*; D005260:Female; D047109:Fetal Development; D006801:Humans; D007223:Infant; D011078:Polychlorinated Biphenyls / Q000097:blood*; D049590:Postpartum Period / Q000097:blood; D011247:Pregnancy