Magnesium protects against preeclampsia seizures
Preeclampsia includes among its afflictions a tendency for seizures. A study just published in the journal Pregnancy Hypertension demonstrates magnesium raises the threshold for seizures in preeclampsia by reducing neuroinflammation. The authors state:
"The mechanism by which MgSO4 [magnesium sulfate] provides seizure prophylaxis in women with preeclampsia (PE) remains unclear, and may be multifaceted. Here, we investigated the effect of MgSO4 on seizure threshold, blood-brain barrier (BBB) permeability and neuroinflammation in a rat model of PE."
Neuroinflammation and BBB permeability are both increased in preeclampsia
They subjected their pregnant (P) and preeclampsia (PE) study animals to seizures by infusions of pentylenetetrazol (PTZ) and while recorrding EEGs and the amount of PTZ required to elicit a seizure compared to a subset treated with magnesium. They measured blood brain barrier (BBB) permeability by quantifying passage of infused sodium fluorescein (NaFl) into the brain. Microglial activation was their metric for neuroinflammation, done by immunostaining for ionized calcium binding adapter molecule. This revealed a specific benefit of magnesium in preeclampsia:
"Seizure threshold was lower in PE compared to P rats that was reversed by MgSO4. BBB permeability was increased in PE, with more NaFl passing into the brain compared to P rats that was unaffected by MgSO4. PE rats had neuroinflammation, characterized by activated microglia that was reversed by MgSO4."
Magnesium reduces neuroinflammation
Among its many virtues, this preeclampsia model highlights the ability of magnesium to reduce neuroinflammation, calming the brain's immune cells (microglia). Also relevant for preeclampsia is magnesium's benefit for hypertension. Alert practitioners note that suboptimal levels of magnesium are ubiquitous. The authors conclude:
"PE was associated with lower seizure threshold, potentially due to increased BBB permeability and neuroinflammation. MgSO4 increased seizure threshold in PE rats through a quiescent effect on microglia without affecting BBB permeability."
Magnesium prevents high blood pressure in pregnancy
Here we can appreciate a study demonstrating that magnesium supplementation also prevents hypertension in the last weeks of pregnancy that was published in Gynecology and Obstetrics. The authors conducted a randomized placebo controlled trial by giving 300 mg magnesium as citrate or placebo from pregnancy week 25 in a randomised double-blind setup to a cohort of pregnant primagravida women with a marked result:
"In the magnesium-supplemented group, the average diastolic blood pressure at week 37 was significantly lower than in the placebo group. The number of women with an increase in diastolic blood pressure of ≥15 mmHg was significantly lower in the magnesium group compared with the women who received placebo. There was an inverse relation between the urinary excretion of magnesium during pregnancy and the diastolic blood pressure."
Preeclampsia: seizures and hypertension controlled by magnesium
Taken together this and similar data in the literature argue in favor of clinicians diligently considering magnesium supplementation for every pregnant woman at risk for preeclampsia. It's hard to argue against this point, particularly considering the low cost and practically absent risk. The authors of the latter study conclude:
"Magnesium supplementation prevented an increase in diastolic blood pressure during the last weeks of pregnancy. The relation between diastolic blood pressure and urinary excretion of magnesium suggests that magnesium is involved in the regulation of blood pressure and that the increase in diastolic blood pressure in pregnancy could be due to a lack of magnesium."