Magnesium supplementation in pregnancy. A double-blind study. [Magnesium substitution in pregnancy. A prospective, randomized double-blind study]. Calcium supplementation reduces the risk of pregnancy-induced hypertension in an Andes population. Comparison of magnesium and methyldopa for the control of blood pressure in pregnancies complicated with hypertension. Preliminary evidence of the effect of calcium supplementation on blood pressure in normal pregnant women. The effect of oral magnesium substitution on pregnancy-induced leg cramps. Expectant management in severe preeclampsia: does magnesium sulfate prevent the development of eclampsia? Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial: a randomised placebo-controlled trial. [Magnesium sulfate in prevention of preterm labor].
The effect of magnesium supplementation in pregnancy was studied in 568 women who were treated with 15 mmol magnesium-aspartate-hydrochloride per day or aspartic acid as placebo given orally during pregnancy from less than or equal to 16 weeks. Allocation to the two groups was performed according to the women's birthdates. Magnesium supplementation during pregnancy was associated with significantly fewer maternal hospitalizations, a reduction in preterm delivery, and less frequent referral of the newborn to the neonatal intensive care unit. The results suggest that magnesium supplementation during pregnancy has a significant influence on fetal and maternal morbidity both before and after delivery. The results of a prospective, randomized double-blind study of magnesium substitution in pregnancy are reported. Of 997 gravidae, 985 were included in the study. Of these, 485 received magnesium aspartate (Mg 5-Longoral) and 500 a placebo. The results show that the course of pregnancy was better in the group which received the magnesium aspartate in a daily dose of 15 mmol (Mg 5-Longoral) than in the group given placebo. Among the women treated with magnesium were fewer premature births (less than 258 days' gestation). The proportion of newborns, small for date (less than 2500 g), was lower, as was the proportion of newborns with intrauterine retardation (greater than 10th percentile). There were significantly fewer cases of EPH gestosis in the magnesium group, and no serious side effects of treatment. In the authors' opinion, magnesium substitution should be included in routine antenatal care. Previous studies have suggested that increased dietary calcium is associated with a decreased occurrence of pregnancy-induced hypertension. In this study 106 young healthy nulliparous women, residing in Quito, Ecuador, were enrolled in a double-blind, randomized, controlled clinical trial. From 24 weeks gestation until delivery they received either 2 g of elemental calcium per day or a placebo. Calcium supplementation was associated with a significantly decreased risk of pregnancy-induced hypertension, with 4.1% developing pregnancy-induced hypertension in the treatment group versus 27.9% in the placebo group. Treatment was associated with a decrease in both systolic and diastolic blood pressure over the course of pregnancy. In addition, there was a small but significant increase in serum ionized calcium levels in the calcium-supplemented group during the treatment period. Although magnesium is now the drug of choice for the prevention of eclamptic seizures only few studies have evaluated whether magnesium may reduce blood pressure in pregnancies complicated with hypertension.
                A total of 33 patients with pregnancy-induced hypertension were randomized to either magnesium or methyldopa treatment. Of these 16 received magnesium and 17 methyldopa. The treatment comprised a 48-hour magnesium infusion followed by oral magnesium tablets until 3 days after delivery or 250 mg methyldopa 4 times a day in a similar period.
                Patients treated with magnesium had 1 day after inclusion a statistically significantly lower systolic blood pressure compared to the level in the methyldopa group (138.1 +/- 11 vs. 147.6 +/- 11 mm Hg; p < 0.05), but no difference was observed in diastolic blood pressure (92.0 +/- 6.6 vs. 96.0 +/- 10.1 mm Hg; NS). From the 5th day of inclusion and until delivery both systolic and diastolic blood pressure were significantly lower in the magnesium group (p < 0.05). Including all blood pressure measurements in a single analysis showed that both systolic (138 +/- 13 vs. 148 +/- 15 mm Hg; p < 0.0001) and diastolic (92 +/- 10 vs. 94 +/- 10 mm Hg; p < 0.05) blood pressure were lower in the magnesium group compared to the methyldopa group. There was no difference between the two groups regarding gestational age at delivery, birth weight, Apgar scores and pH in umbilical cord blood.
                This preliminary study demonstrates that magnesium treatment lowers blood pressure in pregnancies complicated with hypertension. The effect is without any adverse effect on maternal and neonatal well-being.
                Copyright 2000 S. Karger AG, Basel In this study the hypothesis that calcium supplementation during pregnancy can modify blood pressure patterns in a population of normal pregnant women was tested. Thirty-six women with normal single pregnancies, between 20 and 35 years of age, in the second trimester of gestation (15 weeks), were randomly assigned to receive 1 gm of calcium per day (n = 11), 2 gm per day (n = 11), or a placebo (n = 14). No differences were observed at the times of admission into the study (baseline) in demographic and clinical variables or in the calcium intake of each group. Baseline blood pressure measures in several positions also were not different. After the initial blood pressure measures (fifteenth week), five follow-up blood pressure measures were obtained. The supplemented groups had significantly lower diastolic blood pressure than the control subjects between the twentieth and twenty-fourth weeks of gestation. Thereafter, an increase in the control group and the group receiving 1 gm of calcium was observed, but levels were similar at term. On the contrary, patients receiving 2 gm of calcium had blood pressure values that remained significantly lower throughout the third trimester. No differences or clear patterns were observed in the blood levels of calcium, magnesium, phosphorus, and proteins between and within groups during gestation. A possible explanation involving parathyroid hormone is attempted. Our purpose was to determine whether women with pregnancy-related leg cramps would benefit from oral magnesium supplementation.
                Seventy-three women with pregnancy-related leg cramps were interviewed about their symptoms in a prospective, double-blind, randomized trial. Initial serum magnesium levels and diurnal magnesium excretion was determined in 50% of the patients. Oral magnesium or placebo was given for 3 weeks, after which new interviews and laboratory analyses were performed.
                Serum magnesium levels in these patients were at or below the lower reference limit, as is also often the case in healthy pregnant patients. Oral magnesium substitution decreased leg cramp distress (p < 0.05 compared with the placebo group, p < 0.001 compared with initial complaints), but did not significantly increase serum magnesium levels, excess magnesium being excreted as measured by an increase in urinary magnesium levels (p < 0.002).
                Oral magnesium supplementation seems to be a valuable therapeutic tool in the treatment of pregnancy-related leg cramps. Although magnesium sulfate has been traditional or standard treatment for severe preeclampsia and eclampsia to prevent convulsions, its efficiency has always been in doubt and its induced side-effects also make it controversial for use. In this study, 64 patients, diagnosed with severe preeclampsia, were randomized into group I (34 patients) managed with MgSO4, and group II (30 patients) managed without MgSO4. There were no occurrences of eclampsia in either group. Although there was no statistical significance in the final delivery method, group I had a higher rate in cesarean section, in which most were significantly due to fetal distress (p < 0.05). Furthermore, group I had significantly more babies with poor apgar score than group II (p = 0.019). During the treatment period for those with a gestational age of less than 34 weeks, there were two patients with abruptio placentae in group I and the treatment periods were noted to be longer in group II than in group I. From the results of monitoring serum magnesium level in group I, when therapeutic level was achieved, magnesium sulfate induced great discomfort which might have led to the deterioration of the patients' condition. According to this study, magnesium sulfate's minimal efficiency, and its adverse side-effects, also make magnesium sulfate a poor choice in the management of preeclampsia. Therefore, because of our poor understanding of the etiology of preeclampsia, suitable management should be undertaken without magnesium sulfate. Improvement of the patient's pathophysiological condition or termination of pregnancy as early as possible, is recommended. Anticonvulsants are used for pre-eclampsia in the belief they prevent eclamptic convulsions, and so improve outcome. Evidence supported magnesium sulphate as the drug to evaluate.
                Eligible women (n=10141) had not given birth or were 24 h or less postpartum; blood pressure of 140/90 mm Hg or more, and proteinuria of 1+ (30 mg/dL) or more; and there was clinical uncertainty about magnesium sulphate. Women were randomised in 33 countries to either magnesium sulphate (n=5071) or placebo (n=5070). Primary outcomes were eclampsia and, for women randomised before delivery, death of the baby. Follow up was until discharge from hospital after delivery. Analyses were by intention to treat.
                Follow-up data were available for 10,110 (99.7%) women, 9992 (99%) of whom received the allocated treatment. 1201 of 4999 (24%) women given magnesium sulphate reported side-effects versus 228 of 4993 (5%) given placebo. Women allocated magnesium sulphate had a 58% lower risk of eclampsia (95% CI 40-71) than those allocated placebo (40, 0.8%, vs 96, 1.9%; 11 fewer women with eclampsia per 1000 women). Maternal mortality was also lower among women allocated magnesium sulphate (relative risk 0.55, 0.26-1.14). For women randomised before delivery, there was no clear difference in the risk of the baby dying (576, 12.7%, vs 558, 12.4%; relative risk 1.02, 99% CI 0.92-1.14). The only notable difference in maternal or neonatal morbidity was for placental abruption (relative risk 0.67, 99% CI 0.45-0.89).
                Magnesium sulphate halves the risk of eclampsia, and probably reduces the risk of maternal death. There do not appear to be substantive harmful effects to mother or baby in the short term. To observe the efficacy of magnesium sulfate in the treatment of preterm labor, 65 uncomplicated cases of preterm labor between 28 and 36 weeks of gestation were studied prospectively during Sep. 1988-May 1991. They were divided into two groups randomly. 30 cases were treated with magnesium sulfate and 35 cases with barbiturates or bed rest. The prevention of delivery for at least 48 hours after the initiation of therapy was achieved in 23 of the 30 cases (76.67%) of the magnesium sulfate group and in 3 of the 35 cases (8.57%) in the control group. Delay of more than 7 days was achieved in 17 of the 30 cases (56.67%) and in 2 of the 35 cases (5.71%). The postponement of delivery between the two groups. There was highly significantly difference (P less than 0.01). There was a significant correlation of cervical dilation at the onset of treatment to success of controlling preterm labor. In the magnesium sulfate group, the mean magnesium level to achieve tocolysis was 2.8 +/- 0.35 mmol/L (mean +/- s). The side effects to the mothers, fetus, and the neonates were mild and not prominent.(ABSTRACT TRUNCATED AT 250 WORDS)
There is not enough high quality evidence to show that dietary magnesium supplementation during pregnancy is beneficial.
[Note: The 15 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]