Pre-eclampsia is a frequent and life threatening problem for pregnant and postpartum women that can occur prenatally or up to 48 hours after delivery. The primary cause of the syndrome has been unrecognized in the medical field. However, the treatment and prevention of magnesium deficiency has been well understood in the dairy industry and the symptoms of the two conditions are very similar.
We study animals in medical research because it is unethical to experiment on humans. Farmers and vets care for dairy animals because it is ethical and profitable to help maintain their health. What they learn can help us understand other mammals too – such as humans.
Hypomagnesemia, also known as grass staggers, can occur in the pregnant or postpartum cow, but it can also occur in herds feeding on low magnesium fields. Weakness and falls occur in the cattle and they recover when feed is provided that contains adequate magnesium. The best treatment is prevention by providing extra magnesium if the feed has low levels. 
Magnesium deficiency can cause leg cramps, constipation, weakness, falling, cardiac arrythmias, edema and hypertension, anemia and poor immune health, ringing in the ears, irritability and headaches, and when severe seizures are possible.  I have had some of these symptoms – including the “wobbles” – feeling weak in the legs and almost stumbling. These symptoms are quite similar to those described for pre-eclampsia and at its most severe seizures are also a risk.
Current care for a human with pre-eclampsia might involve calcium channel blocker pharmaceuticals prenatally for controlling hypertension and intravenous doses of magnesium sulfate in the ER or delivery room for preventing or treating eclamptic seizures. Calcium causes muscle fibers to contract and magnesium allows them to relax.
Calcium channel blockers are patent-able pharmaceuticals trying to perform the job nature assigned to magnesium. The movement of potassium and sodium through ion channels in nerve cell membranes is well understood. A similar interaction is known about calcium and magnesium in the contraction of muscle fibers. Magnesium is the main gate keeper inside of the cell; it can prevent entry of calcium. When low on magnesium the muscles may be flooded with calcium and the constant contraction of the muscle fibers can turn into early labor cramps and possibly seizures.
Puffy ankles (edema) means intracellular fluid is leaking out and more calcium channel blockers are necessary, but more magnesium please. The prenatal woman is low in magnesium because she has been using extra to grow a baby – she can’t grow a baby out of pharmaceuticals.
Eight percent of pregnancies may be affected by pre-eclampsia/eclampsia and the current medical recommendation suggests that calcium and aspirin might help.  A different source states that the condition is a problem for up to 10% of women in developing nations and affects between 3-5% of pregnancies for women in the USA.  Pregnant people are already told to consume extra calcium in their diets. If that strategy were working then why do eight percent of pregnancies still have pre-eclampsia problems?
Magnesium supplements have been reported to be helpful for preventing leg cramps during pregnancy in one study but results from another study didn’t replicate the results.  A large study has begun based in Brazil that plans to provide the trial group of prenatal participants with two 150 mg magnesium supplements per day throughout the pregnancy in the hopes of preventing pre-eclampsia and reducing the number of infants born prematurely or at a low birth weight.  Another study focused on assessing the difference in long term mineral status of patients who had pre-eclampsia prenatally compared to those who didn’t. The results found that long term calcium status was the same which does not support the current theory that calcium deficiency is involved in the condition. 
A different study focused on the difference in current trace mineral status between patients with pre-eclampsia and those without. Blood levels of copper, zinc, selenium, calcium and magnesium were measured. Copper was the only mineral found to have similar levels between the two groups. The blood level of the other four minerals was significantly lower in women who had pre-eclampsia then in the group without the condition during their pregnancy. 
When the body is too low in magnesium then the body will increase hormone levels that cause a drop in calcium levels. Too much calcium and too little magnesium in the blood can cause heart symptoms so there are several ways the body can prevent an imbalance between blood levels of calcium and magnesium. A study that looked at whether magnesium sensitive genes were involved in blood pressure control during pregnancy did find that one was more active in pregnancy compared the non-pregnant group. The gene TRPM6 was more active in the pregnant group than in women in the control group. 
Other research regarding the condition has noted an increased risk among close family members (mothers, daughters, sisters – if one has pre-eclampsia, other close female relatives are statistically more likely to also experience it in their pregnancies.)
A study that measured the vitamin D, hormone D, parathyroid hormone, albumin, and calcium blood levels of postpartum women who had had pre-eclampsia and those wh0 hadn’t during their pregnancies and found no significant difference in any of the levels between the two groups. Both groups had low vitamin D levels but normal levels of hormone D, parathyroid hormone, albumin and calcium. 
A study at the University of Benin found a significant correlation between low magnesium and increased prevalence of pre-eclampsia. The study concludes with a clear recommendation that consuming magnesium rich foods during pregnancy may improve the outcome:
“Pre-eclampsia and pre-term birth are associated with hypomagnesemia in pregnancy; hence, magnesium supplementation or magnesium-rich diet consisting of green leafy vegetables, soy milk and legumes may improve outcome. 
A review of research regarding magnesium and prenatal health also concluded with a recommendation for pregnant women to consume adequate magnesium rich foods:
This review provides recommendations for further study and improved testing using measurement of red cell magnesium. Pregnant women should be counseled to increase their intake of magnesium-rich foods such as nuts, seeds, beans, and leafy greens and/or to supplement with magnesium at a safe level. 
Magnesium sulfate is used during labor and delivery to help prevent seizures in women with pre-eclampsia/eclampsia. I was told that the large dose feels painfully like fire in the veins. Which makes sense because it is an electrically active ion typically found in large amounts only within cell fluid rather than also freely available within the blood plasma. Some clients were very motivated to eat better if it would help prevent blood pressure problems from reoccurring and reduce the possibility of IV magnesium from being necessary. Simple solutions like pumpkin seeds and the DASH diet may be safer too. The high dose of intravenous magnesium sulfate can lead to cardiac problems and patients who receive the treatment are carefully monitored which takes additional staff time and other medical resources. 
“Raspberry leaves as well as the fruit contain many valuable vitamins needed during pregnancy. As well as containing iron, they are rich in vitamins A, C, B, E, calcium, manganese and magnesium. Magnesium particularly contributes to the strengthening of the uterine muscles.” 
Ibuprofen or other non-steroidal anti-inflammatory drugs (NAISDs) may help protect the infant during pregnancy if an infection is also part of the problem underlying pre-eclampsia. The ibuprofen helps reduce an increase in cytokines. The cytokine flood is an inflammatory reaction that may be associated with an increased risk to the infant for mental health problems developing later in life. 
More information about TRP channels is included in this post about Irritable Bowel Syndrome: http://transcendingsquare.com/2016/03/30/and-what-do-osmomechanical-stress-changes-of-temperature-chili-powder-curry-powder-ginger-benicar-hormone-d-steroids-and-cannabinoids-have-in-common/
Which led me to wonder if there is any association between IBS and pre-eclampsia – one study found some co-occurrence that was not statistically significant. There was an increased risk (25-30%) found for miscarriage and having a diagnosis of IBS and depression/anxiety prior to becoming pregnant (how severe the symptoms was not assessed). 
A hypothesis regarding intrauterine pressure and pre-eclampsia mentions that it is associated with cell stress and decreased magnesium levels were noted:
A brief background regarding TRP channels – they act as pressure release valves so that organs leak rather than overfill. As a visual picture think of blowing up a balloon, eventually you have to stop or it will pop. The TRP channels would allow the balloon to leak instead of popping. The channels are located throughout the body and are formed from a large protein or group of proteins that cross the cell membranes. Magnesium is an electrically active mineral that provides the energy required to keep the channels closed and only allow transport of desired chemicals through the channel.
Having too little magnesium available leaves the channels without energy to stay closed and prevent fluid or other chemicals from crossing through the channel. Depending on the difference in pressure fluid and chemicals might rush into the cell from the surrounding fluid (extracellular fluid) or fluid and chemicals might rush out of the cell (intracellular fluid) into the surrounding fluid.
The hypothesis about intrauterine pressure and pre-eclampsia includes background information on the condition but magnesium is only referenced (see the excerpt above), its role in TRP channels was not discussed.
Emergency guidance suggested having the woman experiencing severe symptoms physically get into a kneeling position or lay horizontally on their left side:
“Within the limitations of this analysis, data suggest that IAP may be altered throughout pregnancy by modifying the maternal position (altering the force direction), with the lowest pressure values obtained in knee–chest and left lateral positions. The negative pressure values obtained in the knee–chest position are important, as inversion of the maternal abdomen may provide an easily available and effective emergency intervention for PE, should this hypothesis be confirmed.” 
The article doesn’t provide further description of the position. My guess is a position that was recommended at the time I was pregnant for helping prevent breech delivery – get on hands and knees and then lower the chest and head to the floor, and then relax and stay there a while, having a pillow and watching TV is okay. Yes, see here, scroll down the page: 
Disclaimer: Opinions are my own and the information is provided for educational purposes within the guidelines of fair use. While I am a Registered Dietitian this information is not intended to provide individual health guidance. Please see a health professional for individual health care purposes.
- Grass Staggers In Cattle & Sheep, http://www.dairy-direct.co.uk/?p=2868
- Magnesium Fact Sheet for Health Professionals, NIH, https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
- Effects of Antenatal exposure to Magnesium Sulfate on Neuroprotection and Mortality in Preterm Infants :Maged M. Costantine, MD, Steven J. Weiner, MS, Obstet Gynecol. 2009 August; 114(2 Pt 1): 354-364
- Magnesium deficiency-induced spasms of umbilical vessels: relation to preeclampsia, hypertension, growth retardation. Pub:Science, 221 (July 22, 1983): pp376(2)Burton M. Altura, Bella T. Altura and Anthony Carella
- Enaruna NO1, Ande A, Okpere EE., Clinical significance of low serum magnesium in pregnant women attending the University of Benin Teaching Hospital. Niger J Clin Pract. 2013 Oct-Dec;16(4):448-53.
- Dalton LM, et al., Magnesium in Pregnancy, Nutr Rev. 2016 Sep;74(9):549-57. https://www.ncbi.nlm.nih.gov/pubmed/27445320
- Ferguson, Patricia. “Turning over a new leaf for pregnancy: London-based medical herbalist and ‘living food educator’ Patricia Ferguson discusses how raspberry leaves can help pregnancy.(Raspberry leaves).” Royal College of Midwives Journal. Ten Alps Publishing. 2009. HighBeam Research. 16 Feb. 2011 .
- edited by Richard A. King, Jerome I. Rotter, Arno G. Motulsky The Genetic Basis of Common Diseases, page 539 https://books.google.com/books?id=xKC4swxJC1UC&pg=PA539&lpg=PA539&dq=intrauterine+pressure+in+black+women%27s+pelvic+structure&source=bl&ots=M9TWK8OdYd&sig=YRYuD908NTDc-CChVhIDWKE1l6c&hl=en&sa=X&ved=0ahUKEwjA6qicgsbTAhVHxlQKHWyWBigQ6AEIQDAE#v=onepage&q=intrauterine%20pressure%20in%20black%20women’s%20pelvic%20structure&f=false
- G. Ghosh, Racial/ethnic differences in pregnancy-related hypertensive disease in nulliparous women,