title: Maternal and fetal levels of methionine and homocysteine in early human pregnancy.
abstract: OBJECTIVE
  To investigate methionine metabolism during normal human embryonic development by measuring levels of methionine and total homocysteine in samples of maternal serum, extra-embryonic coelomic fluid, and amniotic fluid.
  
  
  METHODS
  Cross-sectional observational study.
  
  
  METHODS
  Collaboration between St Bartholomew's Hospital, London, and the University Hospital of Nijmegen in The Netherlands.
  
  
  METHODS
  Twenty-three women with uncomplicated pregnancies between 8 and 12 weeks of gestation before surgical termination of an ultrasonographically normal fetus.
  
  
  METHODS
  Maternal serum samples were collected prior to surgery. Samples of extra-embryonic fluid and amniotic fluids were obtained by transvaginal ultrasound-guided coelocentesis and amniocentesis. Methionine was measured using an amino acid analyser and total homocysteine by high performance liquid chromatography.
  
  
  RESULTS
  Levels of methionine were four times higher in extra-embryonic coelomic fluid and twice as high in amniotic fluid compared with maternal serum. In contrast, the total homocysteine concentrations were much lower in both extra-embryonic coelomic fluid and amniotic fluid than in maternal serum. All differences were significant (P < or = 0.01).
  
  
  CONCLUSIONS
  The comparatively high concentrations of methionine in extra-embryonic coelomic fluid and amniotic fluid, and the concomitant low levels of total homocysteine in these fluids, suggest a role for methionine metabolism during early human pregnancy.
authors.affiliation: Department of Epidemiology, University Hospital Nijmegen, The Netherlands.
authors.forename: R P
authors.initials: RP
authors.lastname: Steegers-Theunissen
authors.forename: N C
authors.initials: NC
authors.lastname: Wathen
authors.forename: T K
authors.initials: TK
authors.lastname: Eskes
authors.forename: B
authors.initials: B
authors.lastname: van Raaij-Selten
authors.forename: T
authors.initials: T
authors.lastname: Chard
mesh_terms: D000653:Amniotic Fluid / Q000378:metabolism; D003430:Cross-Sectional Studies; D005260:Female; D005333:Fetus / Q000378:metabolism*; D005865:Gestational Age; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008715:Methionine / Q000097:blood*; D011247:Pregnancy / Q000378:metabolism*; D011261:Pregnancy Trimester, First
chemical_list: D006710:Homocysteine; D008715:Methionine