title: Phosphorus-31 brain MR spectroscopy in women during and after pregnancy compared with nonpregnant control subjects.
abstract: OBJECTIVE
  A reversible decrease in brain size has been demonstrated during normal pregnancy that is maximal at term and returns to normal after many months. The purpose of this longitudinal study was to use phosphorus-31 MR spectroscopy to determine if metabolic changes explain this physiologic event.
  
  
  METHODS
  Pregnant women (n = 12) were examined at term and up to 6 months after delivery. Nonpregnant control subjects (n = 7) were imaged twice (a month apart) to exclude hormone effects. Brain (31)P MR spectra were acquired at 1.5 T, and intracellular pH was calculated from the chemical shift between phosphocreatine and inorganic phosphate resonances. Statistical analysis was performed by using an analysis of variance.
  
  
  RESULTS
  We found no statistically significant differences in the relative levels of metabolite associated with cerebral bioenergetics and cell membrane metabolism between pregnant women and nonpregnant women. However, a significant increase in cerebral pH was observed in pregnant women at 6 weeks after delivery compared with control subjects (7.074 +/- 0.063 vs 7.017 +/- 0.041; P < .05). pH returned to normal by 6 months after delivery (7.014 +/- 0.010).
  
  
  CONCLUSIONS
  Changes in brain size associated with pregnancy appear to be associated with an increase in intracellular pH after delivery. The observed alkalosis may reflect altered cellular metabolism. These persistent brain perturbations associated with pregnancy indicate that, when postpartum physiologic and pharmacologic changes are measured, long-term effects may be expected in central nervous system processing.
authors.affiliation: Department of Anesthesia, MRC Clinical Sciences Centre, Faculty of Medicine, Hammersmith Hospital Campus, Imperial College London, UK.
authors.forename: Anita
authors.initials: A
authors.lastname: Holdcroft
authors.forename: Lisa
authors.initials: L
authors.lastname: Hall
authors.forename: Gavin
authors.initials: G
authors.lastname: Hamilton
authors.forename: Serena J
authors.initials: SJ
authors.lastname: Counsell
authors.forename: Graeme M
authors.initials: GM
authors.lastname: Bydder
authors.forename: Jimmy D
authors.initials: JD
authors.lastname: Bell
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D009682:Magnetic Resonance Spectroscopy; D010759:Phosphorus Isotopes; D011247:Pregnancy
chemical_list: D010759:Phosphorus Isotopes