Preeclampsia, also known as toxemia, is a complex disorder that affects about 5 to 8 percent of pregnant women. You’re diagnosed with preeclampsia if you have high blood pressure and protein in your urine after 20 weeks of pregnancy. The condition most commonly shows up after you’ve reached 37 weeks, but it can develop any time in the second half of pregnancy, as well as during labor or even after delivery (usually in the first 24 to 48 hours).
Preeclampsia causes your blood vessels to constrict, resulting in high blood pressure and a decrease in blood flow that can affect many organs in your body, such as your liver, kidneys, and brain. When less blood flows to your uterus, it can mean problems for your baby, such as poor growth, decreased amniotic fluid, and placental abruption —when the placenta separates from the uterine wall before delivery.
The role of magnesium begins its importance when we are in the womb. During pregnancy, magnesium helps build and repair body tissue in both mother and fetus. A severe deficiency during pregnancy may lead to preeclampsia, birth defects, and infant mortality. Magnesium relaxes muscles and research suggests that proper levels of magnesium during pregnancy can help keep the uterus from contracting until week 35. Dropping magnesium levels at this point may start labour contractions.
Magnesium is frequently used as the treatment for stopping premature labor and the seizures of eclampsia upon onset, but even more helpful would be to prevent these events by supplementing magnesium throughout the course of pregnancy. Magnesium plays a crucial role in fertility, pregnancy,,, and in early newborn life, and many of the problems associated with pregnancy and birth can be resolved by magnesium supplementation.
Read my essay Magnesium Baths for Safer Pregnancy and Birth for much more information on the use of magnesium in pregnancy. Pregnancy cannot be normal unless magnesium levels are adequate. The concentration of magnesium in the placental and fetal tissues increases during pregnancy. The requirements for this element in a pregnant woman’s organism generally exceed its supply; hence, pregnancy should be considered a condition of “physiological hypomagnesemia.”
Breathlessness in Pregnancy
Many women feel short of breath during pregnancy and often the feeling gets worse as their pregnancy advances. “Three quarters of all pregnant women will experience shortness of breath. Breathlessness can leave you feeling winded, or unable to catch your breath. A short stroll round the block can leave you gasping for air like an Olympian who has just passed the 100m finish mark. During pregnancy, you need about 20 per cent more oxygen. You are now providing oxygen for your baby, the placenta and your uterus, as well as yourself.”
Later in pregnancy, the growing uterus puts pressure on the diaphragm, making women’s breathing more labored – especially if they are carrying their babies high, are carrying multiples, or have excessive amniotic fluid.
The condition of preeclampsia is worsened with falling carbon dioxide levels in the blood from difficulties with breathing. The faster and more shallow the breath the less carbon dioxide (bicarbonates) there is in the blood, the more the vessels will constrict raising blood pressure and reducing oxygen delivery to the cells and the fetus.
Yoga teachers have known forever that special attention needs to be paid to breathing to prepare for natural delivery. However modern medicine has not discovered that breathing retraining during the entire pregnancy (practicing slow breathing) will increase oxygen to both mother and baby insuring better outcomes for mother and child. Low oxygen during pregnancy is dangerous threatening healthy development.
The Breathslim device (originally called the Frolov device in Russia) was designed for asthmatics but is ideal for pregnant women who want to ensure their babies are supplied with the oxygen they need. It is also insurance, as is magnesium, against preeclampsia. I recommend both oral and transdermal methods of magnesium supplementation as well as 20 to 40 minutes a day on the Breathslim device for full oxygenation.
 Rats kept severely magnesium depleted (receiving 1/200 the control magnesium intake) for the entire 21-day period of gestation had no living fetuses at term (Hurley and Cosens, 1970, 1971; Hurley, 1971; Hurley et al., 1976). The shorter the duration of the magnesium deficiency, the fewer implantation sites were affected. When the deficiency was maintained from day 6-12, about 30% of the implantation sites were involved and 14% of the full-term fetuses had gross congenital abnormalities (cleft lip, hydrocephalus, micrognathia or agnathia, clubbed feet, adactyly, syndactyly, or polydactyly, diaphragmatic hernia, and heart, lung, and urogenital anomalies). Milder magnesium deficiency (1/130 control intake) maintained throughout pregnancy resulted in resorption of half the implantation sites and malformation of the living young at term.
 Magnesium Deficiency in the Pathogenesis of Disease, Seelig, M; Part 1, chpt. 2. http://www.mgwater.com/Seelig/Magnesium-Deficiency-in-the-Pathogenesis-of-Disease/chapter3.shtml
 There is mounting evidence of magnesium insufficiency during pregnancy. Experimental acute magnesium deficiency has caused increased parathyroid secretion and even parathyroid hyperplasia (Larvor et al., 1964a; Kukolj et al., 1965; Gitelman et al., 1965, 1968a,b; Lifshitz et al., 1967; Sherwood et al., 1970, 1972; Targovnik et al., 1971). Thus, the possibility that magnesium deficiency is contributory to hyperparathyroidism of pregnancy, which is common despite widespread supplementation with calcium and vitamin D.
 Infants at greatest risk of neonatal hypomagnesemia are low-birth-weight infants, including those suffering from intrauterine growth retardation (IUGR) or premature infants recovering from birth hypoxia or later respiratory distress, and infants born to very young primiparous women or to young mothers who have had frequent pregnancies or multiple births, to preeclamptic mothers, and to diabetic mothers. The incidence of neonatal magnesium insufficiency may be greater than suspected. The tendency of women with preeclampsia or eclampsia to develop rising plasma magnesium levels during the last month of pregnancy, even without magnesium therapy, despite which they retain high percentages of parenterally administered pharmacologic doses of magnesium, suggests that magnesium deficiency might be far more common during pregnancy than is indicated by the incidence of hypomagnesemia. Magnesium Deficiency in the Pathogenesis of Disease, Seelig, M; Part 1, chpt. 2. http://www.mgwater.com/Seelig/Magnesium-Deficiency-in-the-Pathogenesis-of-Disease/chapter3.shtml
 Semczuk M, Semczuk-Sikora A. New data on toxic metal intoxication (Cd, Pb, and Hg in particular) and Mg status during pregnancy. Med Sci Monit. 2001 Mar-Apr; 7(2):332-40.