Pregnant women can apply magnesium sulfate under the guidance of doctors to treat obstetric diseases, such as pre-eclampsia and eclampsia, prevent premature labor, and also prevent cerebral palsy in newborns. Magnesium sulfate used in obstetrics treatment, mainly plays the following roles: 1, prevention of eclampsia: magnesium sulfate can inhibit the central nervous activity, blocking the nerve and muscle connection of the conduction, so as to reduce or lift the role of muscle contraction, used for the prevention and treatment of pre-eclampsia, eclampsia, and prevention of cerebral palsy of newborn; 2, inhibit the contraction of uterus: magnesium ions in magnesium sulfate can antagonize the calcium ion, reduce the concentration of calcium ions in the uterine myometrium, can inhibit the contraction of uterus. Concentration, can inhibit uterine contraction, but strictly speaking, magnesium sulfate does not belong to the birth control drugs; 3, lowering blood pressure: magnesium ions in magnesium sulfate have the effect of lifting the spasm of blood vessels, at the same time can diastole smooth muscle of blood vessels, can alleviate the symptoms of hypertension as well as reduce proteinuria; 4, localized edema: if a pregnant woman due to traumatic injuries caused by the limbs are swollen, you can apply magnesium sulfate wet compresses on the affected area, there is an inflammatory effect of edema. Pregnant women need to apply magnesium sulfate treatment, to monitor the blood magnesium content on time, blood magnesium content is too high may cause magnesium poisoning. Remember not to use magnesium sulfate at will, because magnesium sulfate can cause osmotic pressure changes in the body, improper use may cause paralytic intestinal obstruction, hypocalcemia, respiratory depression, cardiac arrest, neonatal hypermagnesemia and other adverse reactions. Pregnant women should communicate with their doctors if they experience discomfort during treatment to avoid delays.