title: Changes in bone density and metabolism in pregnancy.
abstract: OBJECTIVE
  The impact of pregnancy on maternal bone density remains unclear. As a prerequisite to investigate the pathophysiology of gestational bone metabolism, we sought to document the changes in bone metabolism biochemistry in conjunction with those in selective trabecular/cortical osteodensitometry between early and late pregnancy.
  
  
  METHODS
  A prospective, controlled study in a university hospital was conducted with 43 healthy women, 34 of them during uneventful pregnancy. The main outcome measures are trabecular and cortical bone density measured in the first and third trimesters using peripheral quantitative computed tomography in conjunction with a panel of bone metabolism parameters, including blood parathyroid hormone, calcitonin, osteocalcin, skeletal alkaline phosphatase, and the urinary desoxypyridinoline/creatinine ratio.
  
  
  RESULTS
  Cortical bone density was unaffected by pregnancy. Trabecular bone density changes showed wide interindividual variation, ranging from +1.3 to -20.7% per year, identified as fast losers (less than -3%) and slow losers (more than -3%). Serum osteocalcin levels were lower in slow versus fast bone losers in both trimesters (first: P=0.02, third: P=0.02) and were the only independent parameter to differentiate between fast and slow losers.
  
  
  CONCLUSIONS
  Our data suggest that wide interindividual variation and the failure to provide a separate measure of trabecular bone density account for the conflicting evidence in earlier reports. Serum osteocalcin concentration during the first trimester distinguishes between fast and slow losers of trabecular bone and should be evaluated in future studies as predictor for later bone loss (osteoporosis).
authors.affiliation: Department of Obstetrics, Zurich University Hospital, Zurich, Switzerland. josef.wisser@usz.ch
authors.forename: Josef
authors.initials: J
authors.lastname: Wisser
authors.forename: Ivrea
authors.initials: I
authors.lastname: Florio
authors.forename: Maurus
authors.initials: M
authors.lastname: Neff
authors.forename: Volker
authors.initials: V
authors.lastname: König
authors.forename: Renate
authors.initials: R
authors.lastname: Huch
authors.forename: Albert
authors.initials: A
authors.lastname: Huch
authors.forename: Ursula
authors.initials: U
authors.lastname: von Mandach
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D015519:Bone Density / Q000502:physiology*; D016723:Bone Remodeling / Q000502:physiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D011247:Pregnancy / Q000378:metabolism*; D011261:Pregnancy Trimester, First / Q000502:physiology; D011263:Pregnancy Trimester, Third / Q000502:physiology; D011446:Prospective Studies; D011884:Radius / Q000000981:diagnostic imaging / Q000502:physiology*; D014057:Tomography, X-Ray Computed
chemical_list: D015415:Biomarkers