Cerebral Magnesium Levels in Preeclampsia; A Phosphorus Magnetic Resonance Spectroscopy Study.
BACKGROUND
Magnesium sulfate (MgSO4) is used as a prophylaxis for eclamptic seizures. The exact mechanism of action is not fully established. We used phosphorus magnetic resonance spectroscopy (31P-MRS) to investigate if cerebral magnesium (Mg2+) levels differ between women with preeclampsia, normal pregnant, and nonpregnant women.


METHODS
This cross-sectional study comprised 28 women with preeclampsia, 30 women with normal pregnancies in corresponding gestational week (range: 23-41 weeks) and 11 nonpregnant healthy controls. All women underwent 31P-MRS from the parieto-occipital region of the brain and were interviewed about cerebral symptoms. Differences between groups were assessed by analysis of variance and Tukey's post-hoc test. Correlations between Mg2+ levels and specific neurological symptoms were estimated with Spearman's rank test.


RESULTS
Mean maternal cerebral Mg2+ levels were lower in women with preeclampsia (0.12 mM ± 0.02) compared to normal pregnant controls (0.14 mM ± 0.03) (P = 0.04). Nonpregnant and normal pregnant women did not differ in Mg2+ levels. Among women with preeclampsia, lower Mg2+ levels correlated with presence of visual disturbances (P = 0.04). Plasma levels of Mg2+ did not differ between preeclampsia and normal pregnancy.


CONCLUSIONS
Women with preeclampsia have reduced cerebral Mg2+ levels, which could explain the potent antiseizure prophylactic properties of MgSO4. Within the preeclampsia group, women with visual disturbances have lower levels of Mg2+ than those without such symptoms.
Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
Maria
M
Nelander
Department of Radiology, Uppsala University, Uppsala, Sweden.
Jan
J
Weis
Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.|Center for Clinical Research, Dalarna, Sweden.
Lina
L
Bergman
Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
Anders
A
Larsson
Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.|Department of Clinical Sciences, Karolinska Institute, Danderyd Hospital, Stockholm, Sweden.
Anna-Karin
AK
Wikström
Department of Radiology, Uppsala University, Uppsala, Sweden.
Johan
J
Wikström
D000328:Adult; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D015536:Down-Regulation; D005260:Female; D005865:Gestational Age; D006801:Humans; D008274:Magnesium / Q000378:metabolism*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009778:Occipital Lobe / Q000000981:diagnostic imaging / Q000378:metabolism*; D010296:Parietal Lobe / Q000000981:diagnostic imaging / Q000378:metabolism*; D010758:Phosphorus / Q000737:chemistry*; D011225:Pre-Eclampsia / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D011247:Pregnancy; D055815:Young Adult
D010758:Phosphorus; D008274:Magnesium
31P-magnetic resonance spectroscopy; blood pressure; eclampsia; hypertension; magnesium; magnetic resonance; preeclampsia.