Written by Nandan Roongta, Medical Expert and Gynecologist
The Role of Magnesium in the Body
Magnesium is one of the essential minerals needed by humans in relatively large amounts. Magnesium works with many enzymes and is responsible for a large number of processes in the body, including energy metabolism, glucose utilization, protein synthesis, fatty acid synthesis and breakdown, muscle contraction, almost all hormonal reactions and maintenance of cellular ionic balance. Magnesium also has an important role in modulating vasomotor tone and cardiac excitability.
Magnesium affects calcium homeostasis. It is often suggested to be taken with calcium supplements and many products contain amounts of both minerals. People with low magnesium levels may have low plasma calcium that remains refractory to calcium supplementation until the magnesium deficiency is corrected.
The minimum recommended daily intake of magnesium for adults is 0.25 mmol (6 mg)/kg body weight. Magnesium occurs widely in many foods; dairy products, breads and cereals, legumes, vegetables, animal protein and seafood are all good sources. However, processing of the above foods can lead to marked depletion of magnesium.
Common causes of magnesium deficiency (Hypomagnesaemia) include inadequate dietary intake or gastrointestinal absorption, increased losses through the gastrointestinal or renal systems and increased requirement for magnesium, such as in pregnancy.
Magnesium in Pregnancy
The importance of magnesium in pregnancy has been emphasized by several studies. The need for magnesium increases during pregnancy, and the majority of pregnant women likely do not meet this increased need. Women, especially those from disadvantaged backgrounds, have intakes of magnesium below recommended levels. In addition to the needs of the growth of the fetus and the maternal tissue, elevated renal magnesium excretion is a reason for an increased magnesium requirement during pregnancy, especially after the 18th week of gestation.
Pregnancy represents a physiological situation with increased magnesium requirement. Symptoms of magnesium deficiency such as calf muscle cramps can be easily treated with magnesium supplementation as can neuromuscular disorders or enhanced uterus contractions. Magnesium supplementation can prevent pregnancy-induced hypertension and has a positive effect on the height and maturity of fetuses. Magnesium deficiency or insufficiency during pregnancy may pose a health risk for both the mother and the newborn, with implications that may extend into adulthood of the offspring. Thus far, limited studies have suggested links between magnesium inadequacy and certain conditions in pregnancy associated with high mortality and morbidity, such as gestational diabetes, preterm labor, preeclampsia, and small for gestational age or intrauterine growth restriction. Therefore, 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.
In 1991 Dr. Jean Durlach said, “Primary magnesium deficiency may occur in fertile women. Gestational magnesium deficiency is able to induce maternal, fetal, and pediatric consequences which might last throughout life. Experimental studies of gestational Mg deficiency show that Mg deficiency during pregnancy may have marked effects on the processes of parturition and of postuterine involution. It may interfere with fetal growth and development from teratogenic effects to morbidity: i.e. hematological effects and disturbances in temperature regulation. Clinical studies on the consequences of maternal primary Magnesium deficiency in women have been insufficiently investigated.” Magnesium is frequently used as the treatment for stopping premature labor, and the seizures of eclampsia, at the point it starts, but might be more helpful in preventing these if supplemented throughout the course of pregnancy.
Preeclampsia (also called pregnancy-induced hypertension or toxemia) is a condition that occurs in 7% of all pregnancies, and is responsible for several thousand maternal deaths worldwide each year. It is a rapidly progressive condition characterized by high blood pressure, hyperactive reflexes, edema, headaches, changes in vision, and protein in the urine. In case it escalates to cause seizures, it is then called Eclampsia. Eclampsia is a serious condition that can cause premature labor, premature birth, and cerebral palsy in the newborn.
Generations of midwives have passed down the advice of giving Epsom salts (magnesium sulfate) throughout pregnancy. The power of magnesium in the delivery suite can be seen when a pregnant woman affected by seizures of pregnancy (Eclampsia) immediately responds to the intravenous injection of magnesium which both stops seizures and lowers blood pressure miraculously.
Threatened Preterm labor
Magnesium sulphate has been used in some settings as a tocolytic (uterine relaxant) agent to inhibit uterine activity in women with preterm labour, with the aim of preventing preterm birth. It not only causes the uterine muscles to relax, but also has a role in fetal neuroprotection, and is postulated to help reduce the risk of cerebral palsy and gross motor dysfunction by 30-40% in the babies. Current evidence is enough to support the use of magnesium sulphate in women at imminent risk for preterm delivery before 32 weeks of gestation.
Fetal growth restriction
Magnesium supplementation especially from towards the end of the first trimester of pregnancy was reported to be associated with a reduced risk of fetal growth restriction, and was associated with increased birthweight.
Leg cramps in pregnancy
Leg cramps are common in pregnant women. They become more frequent as pregnancy progresses and are especially troublesome at night. Currently, there is no standard treatment for pregnancy-induced leg cramps. Studies have preliminarily shown that magnesium may be a treatment option for women suffering from pregnancy-induced leg cramps.
Magnesium supplementation among women with gestational diabetes had beneficial effects on the metabolic status and pregnancy outcomes, according to some studies.
Safety of Magnesium use in Pregnancy
Magnesium oxide in doses up to 400 mg is pregnancy category A, which means, it can be used safely in pregnancy.
Current recommendations of Medical societies
Every pregnant woman should be supplemented with 240-480 mg (10-20 mmol) magnesium daily, under supervision of the medical practitioner. Magnesium supplementation should start as soon as possible, continue until birth, and be continued postnatally, since the magnesium requirement of the body also increases during breast-feeding. Side effects of a magnesium supplementation might be soft stools (a welcome effect in cases of constipation), which can be easily avoided by the intake of equal doses during the day. Oral magnesium supplementation is contraindicated in severe renal impairment. Also, excessive magnesium from supplements may cause cramps, diarrhea and toxicity. Parenteral modes of drug delivery like the topical application of magnesium oils do not necessarily ensure a fixed drug dosage per day, but are generally safe in most cases, and may be preferred with the dietary supplementation as a preventive measure, where there is no overt deficiency documented.
The role of Magnesium in Pregnancy
~ Written by Nandan Roongta, Medical Expert and Gynecologist