Nutritional factors and rest reduce pregnancy-induced hypertension and pre-eclampsia in positive roll-over test primigravidas. Expectant management in severe preeclampsia: does magnesium sulfate prevent the development of eclampsia? Supplementary calcium in prevention of pre-eclampsia. Low sodium diet and pregnancy-induced hypertension: a multi-centre randomised controlled trial. Trial of calcium to prevent preeclampsia. (Patho)physiological implications of chronic dietary sodium restriction during pregnancy; a longitudinal prospective randomized study. A randomised controlled trial of intravenous magnesium sulphate versus placebo in the management of women with severe pre-eclampsia. Calcium supplementation and the risk of preeclampsia in Ecuadorian pregnant teenagers. Do women with pre-eclampsia, and their babies, benefit from magnesium sulphate? The Magpie Trial: a randomised placebo-controlled trial.
The possibility of reducing pregnancy-induced hypertension and preeclampsia in primigravidas with low doses of nutritional factors and relative rest in the left lateral position was investigated in a randomized controlled, double-blind trial.
                Seventy-four normotensive women at 28-29 weeks' gestation, judged to be at risk of PIH or pre-eclampsia because they presented with a mean blood pressure of 80 mmHg or higher and a positive roll-over test, were studied. The treatment protocol was received by 37 women and the other 37 women received standard antenatal control until delivery.
                Twenty-nine (78.3%) women in the control group developed PIH and/or pre-eclampsia, as opposed to only 4 (10.8%) cases in the treatment group (P < 0.001). There were no adverse effects of treatment in mothers or in infants.
                This protocol reduces PIH and pre-eclampsia in primigravidas judged to be at risk of hypertension. Further studies are required to evaluate prostacyclin and prostaglandin E2 changes. 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. To study the effect of calcium supplementation on reduction of pre-eclampsia in Iranian women at high risk of pre-eclampsia.
                Thirty pregnant women at high risk of developing pre-eclampsia were randomized to 2 g of daily calcium and placebo. Subjects and investigators were blinded to treatment allocation. The inclusion criteria were positive rollover test, having at least one risk factor for pre-eclampsia, between 28 and 32 weeks of pregnancy, and blood pressure less than 140/90 (mm Hg). Exclusion criteria were having any chronic condition. Pre-eclampsia was defined as systolic/diastolic blood pressure over 140/90 plus proteinuria. All the subjects were followed up to delivery.
                A sevenfold reduction in the occurrence of pre-eclamsia were seen among the calcium group compared with the placebo group (7 out of 15 developed pre-eclampsia in control group vs. 1 out of 15 in calcium group, P=0.014). No major effect on pregnancy induced hypertension was seen (66% in placebo and 76% in calcium group developed hypertension) but the onset of hypertension was delayed 3 weeks in the calcium group. A longer duration of pregnancy was seen in calcium than placebo (mean+/-S.D.=37+/-2 for calcium and 34+/-2 for placebo, P<0.05). Infants born to the calcium group, on average, were 552 g heavier than infants born to the placebo group, P<0.05.
                Calcium supplementation is beneficial for preventing pre-eclampsia among Iranian women at high risk of developing pre-eclampsia. To examine the effectiveness of the standard policy in the Netherlands to prescribe a sodium restricted diet to prevent or to treat mild pregnancy-induced hypertension.
                Multi-centre randomised controlled trial between April 1992 and April 1994.
                Seven practices of independent midwives and one university hospital.
                The experimental group comprised 184 women given a low sodium diet (< or = 50 mmol sodium/day) and a control group of 177 women given a normal diet. Eligible women for inclusion had had a rise of blood pressure, or excessive weight gain or oedema during the antenatal period. The 361 women in the trial were recruited from 2020 nulliparae, of whom 1512 (75%) gave informed consent at the beginning of their pregnancy to participate in the study.
                The difference between highest diastolic blood pressure after randomisation and diastolic blood pressure at the moment of randomisation; referral and admission to hospital for hypertension.
                There was no difference in increase of diastolic blood pressure after randomisation, the percentage of referral and admission to hospital for hypertension, or in obstetric outcome between the two groups. Urinary sodium excretion after randomisation in the normal diet group was significantly higher than in the low sodium group.
                Prescribing a sodium-restricted diet to prevent or to treat mild pregnancy-induced hypertension is not effective. Therefore there is no need to introduce a salt restricted diet in prenatal care, although increasing evidence shows that a low sodium diet prevents hypertension in non-pregnant individuals. Previous trials have suggested that calcium supplementation during pregnancy may reduce the risk of preeclampsia. However, differences in study design and a low dietary calcium intake in the populations studied limit acceptance of the data.
                We randomly assigned 4589 healthy nulliparous women who were 13 to 21 weeks pregnant to receive daily treatment with either 2 g of elemental calcium or placebo for the remainder of their pregnancies. Surveillance for preeclampsia was conducted by personnel unaware of treatment-group assignments, using standardized measurements of blood pressure and urinary protein excretion at uniformly scheduled prenatal visits, protocols for monitoring these measurements during the hospitalization for delivery, and reviews of medical records of unscheduled outpatient visits and all hospitalizations.
                Calcium supplementation did not significantly reduce the incidence or severity of preeclampsia or delay its onset. Preeclampsia occurred in 158 of the 2295 women in the calcium group (6.9 percent) and 168 of the 2294 women in the placebo group (7.3 percent) (relative risk, 0.94; 95 percent confidence interval, 0.76 to 1.16). There were no significant differences between the two groups in the prevalence of pregnancy-associated hypertension without preeclampsia (15.3 percent vs. 17.3 percent) or of all hypertensive disorders (22.2 percent vs. 24.6 percent). The mean systolic and diastolic blood pressures during pregnancy were similar in both groups. Calcium did not reduce the numbers of preterm deliveries, small-for-gestational-age births, or fetal and neonatal deaths; nor did it increase urolithiasis during pregnancy.
                Calcium supplementation during pregnancy did not prevent preeclampsia, pregnancy-associated hypertension, or adverse perinatal outcomes in healthy nulliparous women. To study the possible pathophysiological implications of long continued dietary sodium restriction in pregnancy.
                Longitudinal prospective randomized study of the effects of a low sodium diet compared with unrestricted sodium intake in pregnancy.
                Academic Department of Obstetrics and Gynaecology at Sint Radboud Hospital, Nijmegen, The Netherlands.
                42 healthy nulliparous women.
                A low sodium diet (20 mmol sodium daily) started in the 14th week of pregnancy and stopped after delivery.
                Maternal weight gain, food intake, blood pressure, cardiac output, systemic vascular resistance, haematocrit and birthweight.
                Total maternal weight gain and dietary energy intake during pregnancy and weight at 1 and 6 weeks postpartum were significantly lower in the low sodium group. Blood pressure during pregnancy did not show major differences. Stroke volume and cardiac output during pregnancy were significantly lower in the low sodium group whereas systemic vascular resistance was significantly higher. Haematocrit values in the low sodium group tended to be lower during pregnancy, but were significantly lower at 1 and 6 weeks postpartum than in the unrestricted group. Placental and birthweights were not significantly different between the two groups.
                Chronic dietary sodium restriction during pregnancy is characterized by a diminished body fat accumulation and a reduction in circulating volume, due to a decrease in both plasma and red cell volume, in combination with a high systemic vascular resistance without major effects on blood pressure and birthweight. To determine whether the administration of prophylactic intravenous magnesium sulphate reduces the occurrence of eclampsia in women with severe pre-eclampsia.
                Randomised controlled trial.
                A tertiary referral obstetric unit.
                Eight hundred and twenty-two women with severe pre-eclampsia requiring termination of pregnancy by induction of labour or caesarean section.
                The women were randomised to receive either placebo (saline) or magnesium sulphate intravenously. The investigators were blinded to the contents of the pre-mixed solutions.
                The occurrence of eclampsia in the two groups.
                The data of 699 women were evaluated. Fourteen were withdrawn after randomisation. The overall incidence of eclampsia was 1.8%. Of 345 women who received magnesium sulphate, one developed eclampsia (0.3%); in the placebo group, 11/340 women (3.2%) developed eclampsia (relative risk 0.09; 95% confidence interval 0.01-0.69; P = 0.003).
                The use of intravenous magnesium sulphate in the management of women with severe pre-eclampsia significantly reduced the development of eclampsia. To determine whether increased calcium intake (2 g/day) in pregnancy is effective in reducing the risk of preeclampsia in pregnant teenagers.
                The present study was a prospective, randomized, double-blind, controlled clinical trial. Two hundred sixty teenaged pregnant girls attending the Hospital Gíneco-Obstétrico Isidro Ayora in Quito, Ecuador, were included. Selection criteria were age less than 17.5 years, nulliparity, first prenatal visit before 20 weeks' gestation, and residency in Quito (2800-m altitude). We used a table of random numbers to assign 125 girls to receive 2000 mg of elemental calcium daily, beginning at 20 weeks of gestation and continuing until delivery; 135 women in the control group received a placebo. Blood pressure (BP) was measured twice every 4 weeks until delivery and at 48 hours after delivery. The diagnosis of preeclampsia was defined as BP greater than 140/90 mmHg on at least two occasions more than 6 hours apart and proteinuria greater than 30 mg/dL (over one cross by dipstick on two occasions 4-24 hours apart).
                The average daily calcium intake in this population was approximately 51% of the Recommended Dietary Allowance. Calcium supplementation was associated with a significantly decreased risk of preeclampsia (risk reduction 12.35%; P < .001), with 3.2% (n = 4) developing preeclampsia in the treatment group versus 15.5% (n = 21) in the placebo group. Moreover, calcium supplementation led to a reduction in systolic BP of 9.1 mmHg and in diastolic BP of 6.0 mmHg.
                These results suggest that calcium supplementation during pregnancy in populations with low calcium intake is a safe, effective, and inexpensive preventive measure that significantly reduces the risk of preeclampsia. 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.
In the absence of evidence that advice to alter salt intake during pregnancy has any beneficial effect for prevention of pre-eclampsia or any other outcome, salt consumption during pregnancy should remain a matter of personal preference.
[Note: The citation in the awaiting classification section of the review may alter the conclusions of the review once assessed.]