title: Maternal levels of polychlorinated biphenyls in relation to preterm and small-for-gestational-age birth.
abstract: BACKGROUND
  In developed countries, polychlorinated biphenyls (PCBs) are ubiquitous contaminants of the environment, including foods. Within the range of the resulting low-level exposure, associations of PCBs with lower birth weight have been observed in several studies.
  
  
  METHODS
  To examine further the association of PCBs with birth outcomes, we measured serum levels in 1034 pregnant women who were enrolled in the U.S. Collaborative Perinatal Project in 1959 to 1965 before PCB manufacturing was banned.
  
  
  RESULTS
  The multivariate-adjusted odds ratio for preterm birth among those with PCB levels of >/=4 microg/L of total PCBs, compared with those with <2 microg/L, was 1.1 (95% confidence interval = 0.6-2.2); for the same exposure contrast, the odds ratio for delivering an infant who was small-for-gestational-age at birth was 1.6 (0.7-3.7). Birth weight and length of gestation were essentially unrelated to PCB level.
  
  
  CONCLUSIONS
  In these data, maternal levels of PCBs during pregnancy were essentially unrelated to preterm birth, birth weight, or length of gestation. An association of PCBs with small-for-gestational-age birth was observed, but the results were inconclusive and occurred in the absence of an overall decrease in birth weight.
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC, USA. longnecker@niehs.nih.gov
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Longnecker
authors.forename: Mark A
authors.initials: MA
authors.lastname: Klebanoff
authors.forename: John W
authors.initials: JW
authors.lastname: Brock
authors.forename: Xuguang
authors.initials: X
authors.lastname: Guo
mesh_terms: D000328:Adult; D015986:Confounding Factors, Epidemiologic; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007236:Infant, Small for Gestational Age; D008297:Male; D011078:Polychlorinated Biphenyls / Q000097:blood*; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth; D011297:Prenatal Exposure Delayed Effects; D011446:Prospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D011078:Polychlorinated Biphenyls