Extracellular Calcium and Magnesium in Preeclampsia and Eclampsia

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Extracellular Calcium and Magnesium
in Preeclampsia and Eclampsia
*Idogun E.S, ** Imarengiaye C.O, * Momoh S.M.
The cause of preeclampsia remains unknown and calcium and magnesium supplement are being suggested as
means of prevention. The objective of this study was to assess magnesium and calcium in the plasma and
cerebrospinal fluid of Nigerian women with preeclampsia and eclampsia.
Setting was University of Benin Teaching Hospital, in Nigeria. It was a cross-sectional study comprising of
eleven patients and twenty-three controls. The mean, standard deviation and Standard Error of Mean (SEM)
were calculated. Student ‘t’ test method was applied.
Plasma calcium was significantly lower in patients than controls (9.2 ± 1.02 Vs 9.98 ± 0.87mg/dl, P 0.043) “t”
test. The CSF calcium and magnesium levels were lower in patients than controls, (5.66 ± 1.22 vs 6.67 ± 1.15mg/
dl, P 0.043 and 1.75 ± 0.56 vs 1.91 ± 0.19mg/dl, P 0. < 0.0001) respectively.
There is extracellular calcium and magnesium reduction in patients with preeclampsia and eclampsia. This
reduction may have a cause and effect relationship with these disorders.
KEY WORDS: Pre-eclampsia, Eclampsia, Calcium, Magnesium.
*Idogun E.s, ** Imarengiaye C.o, * Momoh S.m.
*Department of Chemical Pathology College of Medicine, Benin Benin-city. Nigeria.
**Department of Anaesthesiology College 0f Medicine, Benin Benin-city Nigeria.
Correspondence to: Dr. Idogun E.S. Department of Chemical Pathology University of Benin Teaching Hospital
P.M.B 1111, Benin City, Nigeria. E-mail: [email protected]

90 African Journal of Reproductive Health
Preeclampsia is defined as the triad of hyperten-
sion, proteinuria and oedema occurring after 20
It was a cross-sectional study, comprising of
weeks gestation in a previously normo-tensive
eleven patients and twenty-three controls that
woman1 It is specific to human pregnancy and
were randomly selected from among hospital
complicate 6 – 8 % of gestation after week 201
attendees. The patients were selected based on
Preeclampsia is still one of the leading causes of
pre-set criteria by the researchers. The inclusion
maternal and fetal morbidity and mortality.2
criteria for the patients were: age, 16 – 45 years,
Despite active research for many years, the
pregnancy in the third trimester diagnosed
etiology of this disorder remains unknown3,
(preeclampsia), as defined in accordance with
although contributory factors include, obesity,
(U.S) National High Blood Pressure Education
diabetes, calcium deficiency4,5, older maternal age
Program working group12 with or without
and job stress6,7. Environmental and nutritional
eclampsia, going for caesarean section. Patients
factors may therefore play a role in the aetiology
on magnesium sulphate and calcium lactate drugs
of preeclampsia. Therefore there is a need to
were excluded from the study.
explore these factors.
The controls were selected from pregnant
The management of preeclampsia includes
normotensive women also in the third trimester,
medications to reduce high blood pressure, strict
undergoing caesarean section but not diagnosed
bed rest, maintenance of normal salt intake,
as having preeclampsia or eclampsia, in the same
possibly hospitalization and induced delivery or
age range. Excluded from the study are patients
caesarean section. Despite the improved health
with medical complications such as diabetes
care world wide, preeclampsia and eclampsia
continue to take a great toll on life of pregnant
mellitus, renal failure, heart failure or ischaemic
women especially in rural Nigerian communities
heart diseases (diseases that alters vascular
where obstetric interventions may be lacking or
response). Patients and controls were sampled
with a well-designed questionnaire, administered
Research is focusing on prevention8,9 of
by the researchers.
preeclampsia rather than treatment. Among the
Ethical consideration: Ethical approval was
advocated modalities of prevention is calcium
obtained from the hospital research ethical
and magnesium supplementation10,11. This is based
committee. All patients and controls gave their
on the physiology of these intracellular ions in
approval after due explanation by the researchers.
cellular and neuronal metabolism and functions.
The objective of this study was to assess
Laborator y methods: Blood and CSF
magnesium and calcium levels in the plasma and
collections were made in the operating theatre
cerebrospinal fluid of Nigerian women with
during the anaesthetic procedure for caesarean
preeclampsia and eclampsia, with the purpose
section. 5mls of venous blood was collected
of establishing the extracellular status of these
from the cubital veins after the routine aseptic
ions. Magnesium and calcium ions have been
procedures. The blood was dispensed into lithium
implicated in seizure disorders, which often
heparin specimen bottles and was separated after
complicate preeclampsia. It is therefore imperative
centrifugation for 5 – 10 minutes at 3000 rpm.
to evaluate the levels of these ions in our women,
The plasma were harvested with clean Pasteur
with the aim of providing preliminary data that
pipettes and immediately stored frozen at – 200C,
could be useful in the management of preeclampsia
until analysis was carried out for Calcium,
and eclampsia using calcium and magnesium
magnesium and Electrolyte and Urea estimations.
African Journal of Reproductive Health Vol. 11 No.2 August 2007

Extracellular Calcium and Magnesium in Preeclampsia and Eclampsia
The cerebrospinal fluid was taken during lumber
deviation and SEM were calculated. Student ‘t’
puncture procedure for spinal anaesthesia by the
test and correlation statistical methods were
anaesthetist. 2mls of cerebrospinal fluid was
applied. The level of significance was set at P £
obtained and dispensed as follows: one half into
lithium heparin bottle for CSF calcium and
magnesium, estimations while the other half was
put into fluoride oxalate bottle for CSF glucose
Eleven patients and 23 controls were studied
estimation. The CSF samples were not stored as
Table 1. The mean age of the patients was 32 ±
the analyses were done on the same day.
5.72 years, and that of the controls was 33 ±
5.72 years, P 0.027(t-test), 20% (n=7) of the
Laboratory Analytical Procedure
patients were booked compared to 44% (n=15)
All assay methods were well-established methods.
of the controls, and 11.8% (n=4) of the patients
Plasma and CSF magnesium levels were assayed
were unbooked compared to 23.5% (n=8) of
using a spectrophotometric manual method using
the control. Most of the patients and controls
xylidyl blue as the colour indicator13. The kit is
were of parity between 1 and 2.
manufactured by DIALAB. Plasma and CSF
The mean systolic blood pressure was 165.45
calcium was also by spectrophotometric manual
± 30.45 mmHg for patients and 112.61 ± 10.10
method, using O-cresolphthalein – complexone
mmHg for controls, P <0.0001(t-test), The mean
as the colour indicator14. The calcium kits are also
diastolic blood pressure for patients was 108.18
manufactured by DIALAB.
± 20.89 mmHg and 68.68 ± 6.26 mmHg for
controls, P < 0.0001(t-test).
Statistical Analysis
Table 2. Plasma calcium was significantly
All data were analyzed using computer with Instat
higher in controls than patients (9.98 ± 0.87 vs
graphpad soft ware V2.05a. The mean, standard
9.2 ± 1.02 mg/dl, P 0.043(t-test). There was no
Table 1 Some Demographic characteristics of patients and controls
Patients (n=11)
Controls (n=23)
Age (years)

32 ± 5.27
33 ± 5.72
Booking status
Number (n)
Number (n)
Para 0
Para 1
Para 2
Para 3
Para 4
Above para 4
Blood pressure
Systolic (mmHg)
165.45 ± 30.45
112.61 ± 10.10
Diastolic (mmHg)
108.18 ± 20.89

68.69 ± 6.26 P<0.0001
African Journal of Reproductive Health Vol. 11 No.2 August, 2007

92 African Journal of Reproductive Health
significant difference between the plasma
with each other, high magnesium concentrations
magnesium of the patients and controls 1.5 ±
inhibit the release of acetylcholine (Ach) and high
0.28 vs 1.55 ± 0.32mg/dl, P 0.28 (t-test). The
calcium concentration increases release of Ach
mean CSF calcium of patients 5.66 ± 1.22mg/
from pre-synaptic nerve terminal11.
dl was significantly lower than the controls 6.87
During cellular injury and cellular death, there
± 1.15mg/dl, P 0.043(t-test). So also is the CSF
is influx of calcium ions into the cell leading to
magnesium lower in patients than controls 1.75
increased intracellular calcium ions and loss of
± 0.56 vs 1.91 ± 0.19mg/dl, P < 0.0001(t-test).
calcium homeostasis11. This mechanism precedes
Serum calcium : serum magnesium ratio was
cell death and is also seen in reperfusion injuries15
lower in patients than controls 5.9 vs 1.6, so also
We also know that there is vasospasm,
was the serum calcium : CSF calcium ratio 1.4 vs
ischaemia as well as cellular hypoxia in severe
1.6. The serum magnesium : CSF magnesium ratio
preeclampsia and eclampsia which may cause
was also lower in patients than controls, 1.2 vs
reperfusion injury (reversible cell injury) following
1.3 respectively.
treatment. Since magnesium physiologically is
antagonist to calcium11, it follows that in an
attempt to mitigate cellular injury by calcium; there
Calcium and magnesium are two intracellular ions
will also be influx of magnesium during
that are very important for cellular metabolism
reperfusion. This could explain why both calcium
such as muscle contractility, secretions, neuronal
and magnesium were reduced in the blood and
activity as well as cellular death15.
CSF of our patients. This hypothesis will need to
Our result shows that there are reduced
be tested by well-controlled experimental studies.
calcium and magnesium levels in patients with
It has been estimated that magnesium intake
preeclampsia. This is consistent with findings in
has declined by more than half during this
other studies5,10,11. While the cause of preeclampsia
century11, because of a reduction in magnesium
remain elusive to scientific knowledge. Magnesium
with the ecosystem resulting in reduced magnesium
and calcium deficiencies are thought to be
content of food items. The magnesium and
implicated4,10,16. Studies from the early 1950s first
calcium content of food is further compromised
elucidated the nature of the effects of calcium
with overcooking, processing and reprocessing
and magnesium ions at the neuromuscular
of food products.
junctions11. Magnesium competes for a prejunc-
The consequences of low magnesium may
tional site with calcium ions11. The ions competed
lead to a reduction in cerebral blood flow, cerebral
Table 2: Extracellular concentration (mean) of calcium and magnesium in patients and controls
Patients (n=11)
Controls (n=23)
Serum calcium (mg/dl)
9.2 ± 1.02
9.8 ± 0.87
Serum magnesium (mg/dl)
1.5 ± 0.28
1.55 ± 0.32
CSF calcium (mg/dl)
5.66 ± 1.22
6.87 ± 1.15
CSF magnesium (mg/dl)
1.75 ± 0.56
1.91 ± 0.19
< 0.0001
Serum Ca:Mg ratio
Serum Ca:CSF Ca ratio
Serum Mg:CSF Mg ratio
n = number
S = Significant
NS = Not Significant
African Journal of Reproductive Health Vol. 11 No.2 August 2007

Extracellular Calcium and Magnesium in Preeclampsia and Eclampsia
vasospasm and increase in neuronal burst.
for the clinical manifestations that are observed
Macdonald et al17 have shown experimentally that
in this disease, since both ions are important in
magnesium has a vasoprotective effects. And this
cellular and neuronal metabolism as well as cell
explains the use of magnesium sulphate as a
membrane stability11.
neuroprotectant and antivasospastic agent.
Magnesium (mg ++) may increase cerebral blood
flow and reduces the contraction of cerebral
There are reduced extracellular calcium and
arteries caused by various stimuli17. The clinical
magnesium levels in patients with preeclampsia
implication of low magnesium seen in our patients
and eclampsia. These lower levels may have a
may be vascular contractility, low cerebral blood
cause and effect relationship with these disorders,
flow and a tendency to eclamptic fits. Physicians
and these data may therefore be found useful
now agree that the medication for seizures in
when considering interventional management of
preeclampsia is magnesium sulfate18. The systemic
preeclampsia and eclampsia using magnesium
effects of magnesium include vasodilatation and
and calcium supplementation.
an increase in blood flow, these prevent eclampsia
by selectively dilating the cerebral vasculature and
relieving the cerebral vasospasm associated with
We want to thank the secretariat staff of chemical
preeclampsia. In the eclamptic patient, it will
pathology department for typing this manuscript.
prevent recurrent seizures which is beneficial in
And we also thank all the resident doctors in the
reducing the mortality and morbidity in both
same department and the department of
mother and fetus18.
Anaesthesiology for their co-operation in sample
Calcium and magnesium ratio are important
in excitability and burst firing of neuronal cells19.
We found low extracellular fluid concentrations
of calcium and magnesium as well as reduced
ratio of calcium and magnesium in our study.
Redman CWG, Jefferis M. Revised definition of
These extracellular changes could explain why
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