Magnesium sulfate prophylaxis in preeclampsia: evidence from randomized trials

Practical guide for the management of hypertensive disorders during pregnancy

Hypertensive disorders of pregnancy, including gestational hypertension, preeclampsia, and eclampsia, are a worldwide health problem. Hypertensive disorders of pregnancy affect more than 10% of pregnancies and are associated with increased mortality and morbidity for both mother and fetus. Although patients' outcomes and family's experience will always be the primary concern regarding hypertensive complications during pregnancy, the economic aspect of this disease is also worth noting. Compared with normotensive pregnancies, those related with hypertension resulted in an excess increase in hospitalization and healthcare cost. Hence, the focus of this review is to analyze hypertensive disorders of pregnancy and to present practical tips with clear instructions for the clinical management of hypertensive disorders of pregnancy. This overview offers a detailed approach from the diagnosis to treatment and follow-up of a pregnant women with hypertension, evidence based, to support these instructions.

Effect of Mg-Gluconate on the Osmotic Fragility of Red Blood Cells, Lipid Peroxidation, and Ca2+-ATPase (PMCA) Activity of Placental Homogenates and Red Blood Cell Ghosts From Salt-Loaded Pregnant Rats

Preeclampsia (PE) is a pregnancy-specific syndrome with multisystem involvement which leads to fetal, neonatal, and maternal morbidity and mortality. A model of salt-loaded pregnant rats has been previously studied, sharing several pathological characteristics of preeclamptic women. In this study, it was compared the effects of the treatment with an oral magnesium salt, magnesium gluconate (Mg-gluconate), on the osmotic fragility of red blood cells, lipid peroxidation, and PMCA activity of placental homogenates and red blood cell ghosts in salt-loaded pregnant rats. Mg-gluconate has a higher antioxidant capacity than MgSO₄ due to the presence of several hydroxyl groups in the two anions of this salt. Salt-loaded pregnant rats received 1.8% NaCl solution ad libitum as a beverage during the last week of pregnancy. On day 22nd of pregnancy, the rats were euthanized and red blood cells and placenta were obtained. Salt-loaded pregnant rats showed an increased level of lipid peroxidation and a lowered PMCA activity in placental and red blood cell ghosts, as well as an increased osmotic fragility of their red blood cells. The treatment of the salt-loaded pregnant rats with Mg-gluconate avoids the rise in the level of lipid peroxidation and the concomitant lowering of the PMCA activity of their red blood cell membranes, reaching values similar to those from control pregnant rats. Also, this treatment prevents the increase of the osmotic fragility of their red blood cells, keeping values similar to those from control pregnant rats. Mg-gluconate seems to be an important candidate for the replacement of the MgSO₄ treatment of preeclamptic women.

Increased Cardiac Arrhythmia After Pregnancy-Induced Hypertension: A South Korean Nationwide Database Study

Background

Although pregnancy‐induced hypertension (PIH) is associated with an elevated cardiovascular risk, long‐term studies or prepregnancy baseline data are scarce. Therefore, using a large nationwide cohort with prepregnancy periodic health screening data, we investigated whether clinically significant arrhythmia incidence increases after PIH.

Methods and Results

Data were extracted from the Korea National Health Insurance database and combined with the National Health Screening Examination database; women who gave birth between 2007 and 2015 and underwent the national health screening test within a year before pregnancy were followed up until 2016. We excluded women who had a diagnosis of arrhythmia within 1 year before pregnancy. The primary outcome was significant arrhythmia during the year after delivery. Secondary analysis included only specific diagnostic codes of arrhythmia with clinical significance. Additionally, the risk of arrhythmia was stratified by the use of magnesium sulfate. Of 2 035 684 women (PIH; n=37 297 versus normotensive pregnancy; n=1 998 387), the PIH group had a higher prepregnancy risk profile and showed a higher incidence of arrhythmia than women with normotensive pregnancies within 1 year. Women with PIH had a significantly higher risk of atrial flutter/fibrillation and atrioventricular block, but not lethal arrhythmias. Other predictors of arrhythmia development included advanced maternal age and cesarean section. Stratified analysis showed a higher risk of arrhythmia with magnesium sulfate use.

Conclusions

PIH was significantly associated with the development of arrhythmia within 1 year after delivery. Nevertheless, the incidence of lethal arrhythmias was not increased by PIH. Arrhythmia, especially atrial fibrillation, may largely contribute to increasing the future cardiovascular risk in women with a PIH history.

Formulation, Optimization, and In vivo Evaluation of Gastroretentive Drug Delivery System of Nifedipine for the Treatment of Preeclampsia

The study aimed to develop gastroretentive drug delivery system of nifedipine, its optimization, and in vivo evaluation. Bilayered tablet of nifedipine was prepared using central composite design with 3 factors, 5 responses, and 15 experimental trials. Response surface methodology along with numerical and graphical optimization was used to select the best formulation. Scanning electron microscopy study of optimized tablet at different time interval was carried out which showed formation of porous structure on the tablet surface. In vivo studies for optimized formulation were carried out on 10 healthy human volunteers and obtained pharmacokinetic parameters were compared with the marketed formulation, "Nicardia XL." Optimized formulation containing 3.083 mg HPMC K15M, 29.859 mg HPMC E15LV, and 3.541 mg Carbopol 974P releases the drug in a desired manner and remain buoyant for more than 12 h in human stomach. Both the formulations were found to have similar in vitro release profile (f1 4.5089 and f2 55.8274) and also were found to be bioequivalent. Finally, the stability study of the optimized formulation proved the integrity of the optimized formulation. Hence, the data suggest gastroretention as a promising approach to enhance bioavailability of nifedipine.

The burden of hypertensive disorders of pregnancy in Africa: A systematic review and meta-analysis

Hypertensive disorders of pregnancy (HDP) are a major contributor to maternal and perinatal morbidity and mortality, especially in resource-limited settings. Little is known about the magnitude of HDP in Africa. We conducted the first systematic review and meta-analysis to summarize available data on the prevalence of HDP in Africa. We did a comprehensive literature search to identify review paper published from January 1, 1996, to September 30, 2017, and searched the reference list of retrieved review paper. We used a random-effects model to estimate the overall and type-specific prevalence of HDP in Africa. We included 82 studies published between 1997 and 2017 reporting data on a pooled sample of 854 304 women during pregnancy or puerperium. Most studies were hospital-based, conducted in urban settings across 24 countries. In this population, the overall prevalence of HDP was 100.4‰ (95% CI: 81.4-121.2). The prevalence was 49.8‰ (95% CI: 32.3-70.7) for gestational hypertension, 14.7‰ (95% CI: 11.6-18.2) for chronic hypertension, 9.2‰ (95% CI: 4.2-16.0) for superimposed preeclampsia, 44.0‰ (95% CI: 36.7-52.0) for preeclampsia, 22.1‰ (95% CI: 14.8-30.8) for severe preeclampsia, 14.7‰ (95% CI: 8.1-23.2) for eclampsia and 2.2‰ (95% CI: 1.2-3.4) for HELLP syndrome. Prevalence of HDP was significantly higher in Central and Western Africa; there was a consistent tendency of increasing HDP prevalence with income at the country level. In conclusion, the burden of HDP in Africa is high, with about one in 10 pregnancies affected. The higher rate of severe forms of HDP that are associated with significant maternal and perinatal mortality is a major concern in the region.

A retrospective review of on-admission factors on attainment of therapeutic serum concentrations of magnesium sulfate in women treated for a diagnosis of preeclampsia

Introduction: There is little information on the effect of maternal characteristics and on-admission laboratory parameters to the therapeutic serum magnesium sulfate (MgSO₄) levels in women with preeclampsia (PE). We sought to identify factors that may predict timely attainment of therapeutic serum magnesium levels after intravenous administration for seizure prophylaxis.Materials and methods: On-admission factors of 360 women with PE who received intravenous MgSO₄ (4-g loading and 2-g/h maintenance) for seizure prophylaxis were retrospectively reviewed. Parameters of those who attained therapeutic serum concentrations (4.8-8.4 mg/dL) within 2 h (Group A) and those who did not (Group B) were compared.Results: There was no seizure or magnesium toxicity in this cohort. Median (min-max) level of serum magnesium was 4.3 (2.5-8.4) mg/dL. Women in Group A (n = 105) had lower gestational age, body mass index (BMI), and platelets count, higher blood urea nitrogen (BUN), serum creatinine, uric acid, direct bilirubin, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, prothrombin, and partial thromboplastin times than those in Group B (n = 255) (p < .05). Women with mild PE were less likely to attain therapeutic serum magnesium levels compared with those with severe phenotypes (adjusted OR 23.57, 95% CI 8.20-67.76 versus adjusted OR 14.72, 95% CI 3.56-60.89, respectively; p < .05), which may be explained by their significantly lower serum BUN and uric acid (p < .05).Conclusions: On-admission factors, especially BMI and renal clearance indices, of women with PE may affect timely attainment of therapeutic serum magnesium levels. Validation of its clinical impact requires further study focusing on women with severe PE.

Reversal with sugammadex for rocuronium-induced deep neuromuscular block after pretreatment of magnesium sulfate in rabbits

Background

Magnesium sulfate (MgSO₄) has been used in the treatment of pre-eclampsia, hypertension and arrhythmia. Magnesium enhances the neuromuscular block of rocuronium. This study has been conducted to evaluate the reversal efficacy of sugammadex from deep rocuronium-induced neuromuscular block (NMB) during consistent pretreatment of MgSO₄ in rabbits.

Methods

Twenty-eight rabbits were randomly assigned to four groups, a control group or study groups (50% MgSO₄ 150–200 mg/kg and 25 mg/kg/h IV), and received rocuronium 0.6 mg/kg. When post-tetanic count 1–2 appeared, sugammadex 2, 4, and 8 mg/kg was administered in the 2-mg group, control and 4-mg group, and 8-mg group, respectively. The recovery course after reversal of sugammadex administration was evaluated in each group.

Results

The mean serum concentration of magnesium was maintained at more than 2 mmol/L in the study groups, and the total dose of MgSO₄ was more than 590 mg. The reversal effect of sugammadex on rocuronium-induced NMB in pretreated MgSO₄ was not different from that in the group without MgSO₄. The recovery time to train-of-four ratio 0.9 after sugammadex administration in the 2-mg group was longer than in the other groups (P < 0.001); there were no other significant differences among the groups.

Conclusions

The reversal of sugammadex from a deep rocuronium-induced NMB during large pretreatment of MgSO₄ was not affected. However, we should consider that the reversal effect of sugammadex varied depending on the dose.

Oxidative stress in preeclampsia and the role of free fetal hemoglobin

Preeclampsia is a leading cause of pregnancy complications and affects 3-7% of pregnant women. This review summarizes the current knowledge of a new potential etiology of the disease, with a special focus on hemoglobin-induced oxidative stress. Furthermore, we also suggest hemoglobin as a potential target for therapy. Gene and protein profiling studies have shown increased expression and accumulation of free fetal hemoglobin in the preeclamptic placenta. Predominantly due to oxidative damage to the placental barrier, fetal hemoglobin leaks over to the maternal circulation. Free hemoglobin and its metabolites are toxic in several ways; (a) ferrous hemoglobin (Fe(2+)) binds strongly to the vasodilator nitric oxide (NO) and reduces the availability of free NO, which results in vasoconstriction, (b) hemoglobin (Fe(2+)) with bound oxygen spontaneously generates free oxygen radicals, and (c) the heme groups create an inflammatory response by inducing activation of neutrophils and cytokine production. The endogenous protein α1-microglobulin, with radical and heme binding properties, has shown both ex vivo and in vivo to have the ability to counteract free hemoglobin-induced placental and kidney damage. Oxidative stress in general, and more specifically fetal hemoglobin-induced oxidative stress, could play a key role in the pathology of preeclampsia seen both in the placenta and ultimately in the maternal endothelium.

Magnesium sulfate affords protection against oxidative damage during severe preeclampsia

INTRODUCTION

MgSO4 is the drug of choice to prevent seizures in preeclamptic pregnant women, but its mechanism of action at the molecular level remains an enigma. In previous works, we found that treating preeclamptic women with MgSO4 reduces the lipid peroxidation of their red blood cell membranes to normal levels and leads to a significant reduction in the osmotic fragility of the red blood cells that is increased during preeclampsia. In addition, the increase in lipid peroxidation of red cell membranes induced by the Fenton reaction does not occur when MgSO4 is present.

METHODS

The antioxidant protection of MgSO4 was evaluated in UV-C-treated red blood cell ghosts and syncytiotrophoblast plasma membranes by measuring their level of lipid peroxidation. The interaction of MgSO4 with free radicals was assessed for its association with the galvinoxyl radical, the quenching of H2O2-induced chemiluminescence and its effect on sensitized peroxidation of linoleic acid.

RESULTS

a) MgSO4 protected red blood cell ghosts and the syncytiotrophoblast plasma membranes of normotensive pregnant women against lipid peroxidation induced by UV-C irradiation. b) MgSO4 does not seem to scavenge the galvinoxyl free radical. c) The quenching of the H2O2-enhanced luminol chemiluminescence is increased by the presence of MgSO4. d) The peroxidation of linoleic acid is significantly blocked by MgSO4.

DISCUSSION

MgSO4 may provide protection against oxidative damage of plasma membranes through interactions with alkyl radicals.

Proliferation of trophoblasts and Ki67 expression in preeclampsia

BACKGROUND/AIMS

Preeclampsia is a pregnancy-specific disease with the increased risk of maternal morbidity and mortality. It is characterised by placental vascular dysfunction. Despite the numerous studies on preeclampsia, studies evaluating proliferation of villous trophoblasts in preeclamptic placentas are limited. Ki67 is a proliferation marker that expresses in the nuclei of proliferating cells. In this study, we examined the proliferation of villous trophoblasts in placentas of preeclamptic patients by using Ki67 and compared it with placentas of normal pregnant patients.

MATERIAL AND METHODS

The current study is a prospective one, including 15 placentas from preeclamptic patients and 14 placentas from normal pregnancies as controls. For detection of proliferation in villous trophoblasts, Ki67 was used.

RESULTS

The Ki67 index was 11.48±1.67% in normal patients and 15.53±2.28% in preeclamptic patients. There was a difference in Ki67 index between the two groups (p < 0.001).

CONCLUSION

Our results support the opinion that trophoblasts undergo regeneration hyperplasia as a result of injuries arising on the villous surface in preeclampsia. Proliferation of trophoblasts may contribute the development of preeclampsia.

Effect of hypoxia on the calcium and magnesium content, lipid peroxidation level, and Ca²⁺-ATPase activity of syncytiotrophoblast plasma membranes from placental explants

In the current study the possible relationship between the Ca²⁺/Mg²⁺ ratio of human syncytiotrophoblast plasma membranes and their lipid peroxidation and Ca²⁺-ATPase activity was determined. Syncytiotrophoblast plasma membranes of placental explants cultured under hypoxia increased their lipid peroxidation and Ca²⁺ content, diminished their Ca²⁺-ATPase activity, and kept their Mg²⁺ content unchanged. Membranes preincubated with different concentrations of Ca²⁺ increased their Ca²⁺ content without changes in their Mg²⁺ content. There is a direct relationship between Ca²⁺ content and lipid peroxidation of the membranes, as well as an inverse relationship between their Ca²⁺ content and Ca²⁺-ATPase activity. On the contrary, preincubation of membranes with different concentrations of Mg²⁺ showed a higher Mg²⁺ content without changing their lipid peroxidation and Ca²⁺-ATPase activity. Explants cultured under hypoxia in the presence of 4 mM MgSO₄ showed similar values of lipid peroxidation and Ca²⁺-ATPase activity of their membranes compared to those of explants cultured under normoxia. Increased Ca²⁺ content of the membranes by interacting with negatively charged phospholipids could result in destabilizing effects of the membrane structure, exposing hydrocarbon chains of fatty acids to the action of free radicals. Mg²⁺ might exert a stabilizing effect of the membranes, avoiding their exposure to free radicals.

Early onset preeclampsia in subsequent pregnancies correlates with early onset preeclampsia in first pregnancy

OBJECTIVE

Preeclampsia is a major complication of pregnancy and its occurrence in a first pregnancy is a major risk factor for recurrence in subsequent pregnancies. Whether the time of onset or the severity of preeclampsia in a first pregnancy is associated with the incidence of recurrent preeclampsia is not clear. We performed a retrospective study to analyse the incidence of recurrent preeclampsia and associations of the time of onset and the severity of preeclampsia between first preeclampsia and recurrent preeclampsia.

STUDY DESIGN

Ninety-two women with previous preeclampsia who had a second pregnancy in a 4 year period were included. Data on the first and second pregnancies were obtained and included maternal age, maternal height and weight, gestation week at onset of preeclampsia and at delivery, blood pressure, proteinuria, interval between pregnancies and birth weights.

RESULTS

Fifty-five women with previous preeclampsia developed recurrent preeclampsia (59.8%). The difference in the incidence of recurrent early and late onset preeclampsia was not significant different (65.3% versus 53.4%, p>0.05). The difference in the incidence of mild or severe disease in those who experienced recurrent preeclampsia was also not significant (59.6% versus 60%, p>0.05). The severity of preeclampsia in second pregnancy was not associated with the severity of preeclampsia in first pregnancy. However 93.7% women with previous early onset preeclampsia developed early onset preeclampsia in second pregnancy and 56.5% women with previous late onset preeclampsia developed early onset preeclampsia in second pregnancy. In addition, 76.2% women with previous mild preeclampsia developed severe preeclampsia in second pregnancy. The baby weight in recurrent preeclampsia was significantly decreased compared to that in first pregnancy with preeclampsia.

CONCLUSION

Our data demonstrate that there was no association between the incidence of recurrent preeclampsia and the time of onset or severity of preeclampsia in first pregnancy. But our data here may suggest that women with early onset preeclampsia in first pregnancy are more likely to experience early onset preeclampsia in second pregnancy. The severity of recurrent preeclampsia is increased regardless the severity in first pregnancy.

Maternal near miss and death among women with severe hypertensive disorders: a Brazilian multicenter surveillance study

BACKGROUND

Hypertensive disorders represent the major cause of maternal morbidity in middle income countries. The main objective of this study was to identify the prevalence and factors associated with severe maternal outcomes in women with severe hypertensive disorders.

METHODS

This was a cross-sectional, multicenter study, including 6706 women with severe hypertensive disorder from 27 maternity hospitals in Brazil. A prospective surveillance of severe maternal morbidity with data collected from medical charts and entered into OpenClinica®, an online system, over a one-year period (2009 to 2010). Women with severe preeclampsia, severe hypertension, eclampsia and HELLP syndrome were included in the study. They were grouped according to outcome in near miss, maternal death and potentially life-threatening condition. Prevalence ratios and 95% confidence intervals adjusted for cluster effect for maternal and perinatal variables and delays in receiving obstetric care were calculated as risk estimates of maternal complications having a severe maternal outcome (near miss or death). Poisson multiple regression analysis was also performed.

RESULTS

Severe hypertensive disorders were the main cause of severe maternal morbidity (6706/9555); the prevalence of near miss was 4.2 cases per 1000 live births, there were 8.3 cases of Near Miss to 1 Maternal Death and the mortality index was 10.7% (case fatality). Early onset of the disease and postpartum hemorrhage were independent variables associated with severe maternal outcomes, in addition to acute pulmonary edema, previous heart disease and delays in receiving secondary and tertiary care.

CONCLUSIONS

In women with severe hypertensive disorders, the current study identified situations independently associated with a severe maternal outcome, which could be modified by interventions in obstetric care and in the healthcare system. Furthermore, the study showed the feasibility of a hospital system for surveillance of severe maternal morbidity.

Effect of magnesium sulfate exposure on term neonates

OBJECTIVE

To compare neonatal intensive care unit and special care unit (NICU) admission rates between term neonates exposed to antenatal magnesium sulfate (MS) and those unexposed.

STUDY DESIGN

We performed a retrospective cohort study of all singleton neonates ≥37 weeks born to women with pre-eclampsia from August 2006 to July 2008. Cases were defined by antenatal exposure to MS and controls by absence of MS exposure. The primary outcome was NICU admission. Data were analyzed via univariable and multivariable regression analyses.

RESULT

In all, 28 (14.7%) out of 190 MS-exposed neonates ≥37 weeks were admitted to the NICU, compared with 4 (5.4%) of 74 non-exposed neonates (P=0.04). This association persisted after controlling for potential confounding variables including severe pre-eclampsia and cesarean delivery (AOR 3.69, 1.13 to 11.99). NICU admission was associated in a dose-dependent relationship with total hours and mean dose of MS exposure. Number needed to harm with MS was 11 per NICU admission. Among neonates admitted to the NICU, MS-exposed were more likely to require fluid and nutritional support than unexposed neonates (60.7 vs 0%, P=0.04), and trended toward more frequent requirement for respiratory support and greater length of stay.

CONCLUSION

In term neonates, MS exposure may be associated independently with NICU admission in a dose-dependent relationship. Requirements for fluid and nutritional support are common in this group, likely due to feeding difficulties in exposed neonates. Assessment of acute care needs among all neonates exposed to MS for maternal eclampsia prophylaxis should be considered.

Correlation of magnesium levels in cord blood and maternal serum among pre-eclamptic pregnant women treated with magnesium sulfate

AIM

The aim of this study was to determine the correlation between cord blood and maternal serum magnesium levels among pre-eclamptic pregnant women treated with magnesium sulfate.

MATERIALS AND METHODS

A total of 36 pregnant women, >28weeks' gestation, diagnosed with pre-eclampsia and treated with magnesium sulfate (MgSO(4) ), were enrolled. Maternal and umbilical cord blood samples were obtained immediately after delivery and sent for determination of magnesium and calcium levels.

RESULTS

  Mean maternal age was 27.4±6.4years and mean gestational age was 38.1±1.8weeks. Most were diagnosed with pre-eclampsia (94.5%), others had HELLP syndrome. Mean total MgSO(4) the women received was 14.4±6.0g and mean duration of treatment was 5.1±3.3h. Mean maternal serum and cord blood magnesium levels were 2.2±0.4 and 1.8±0.3mmol/L, respectively. Maternal magnesium and calcium levels showed significant positive correlation with their levels in cord blood (P<0.001). Significant positive correlation was found between total dose as well as duration of MgSO4 and maternal and cord blood magnesium levels (P<0.001) but was inversely correlated with maternal and cord blood calcium levels.

CONCLUSIONS

Maternal serum magnesium and calcium levels were correlated with cord blood levels in pre-eclamptic pregnant women who received MgSO4 therapy.

Magnesium sulfate: past, present, and future

First used anecdotally for the control of eclamptic seizures in the early 1900s, magnesium sulfate remains 1 of the most commonly used medications in obstetric practice today. Over the past 95 years, there have been countless research studies investigating the efficacy of magnesium sulfate for the management of eclampsia, preeclampsia, preterm labor, and most recently for prevention of cerebral palsy. The majority of this evidence undeniably supports the use of magnesium sulfate as the drug of choice for the prevention and treatment of eclampsia when evidence of severe disease is present. On the other hand, studies have not shown magnesium sulfate to be comparably more effective than other tocolytics for treating preterm labor, nor is there agreement on whether the evidence supports its use as a neuroprotective agent for prevention of cerebral palsy. The exact mechanism of action of magnesium sulfate remains largely hypothetical, and parenteral use has the potential to cause significant morbidity in high doses. This article reviews magnesium sulfate's remarkable history in obstetric practice and includes a summary of the evidence related to each of the controversies. An initial review of the physiology of magnesium sulfate is essential to understanding pharmacodynamic actions, dosing guidelines, and safety requirements.

Neonatal medical admission in a term and late-preterm cohort exposed to magnesium sulfate

OBJECTIVE

The purpose of this study was to estimate neonatal intensive care unit and special care unit (NICU) admission rates and care needs among term and late-preterm neonates who are exposed to antenatal magnesium sulfate.

STUDY DESIGN

We conducted a retrospective cohort study of all singleton neonates of ≥35 weeks' gestation who were exposed immediately antenatally to magnesium sulfate for maternal eclampsia prophylaxis (August 2006 through July 2008).

RESULTS

Fifty-one of 242 neonates (21.1%) who, at ≥35 weeks' gestation, had been exposed to antenatal magnesium sulfate were admitted to the NICU. NICU admission was associated in a dose-dependent fashion with total hours and mean dose of magnesium: >12 hours exposure, odds ratio, 2.81 (95% confidence interval, 1.31-6.03); >30 g exposure, odds ratio, 2.59 (95% confidence interval, 1.22-5.51). Infants in NICU who were diagnosed with hypermagnesemia required fluid or nutritional support more frequently (91.3% vs 39.3%; P < .001) than those without hypermagnesemia.

CONCLUSION

Antenatal magnesium sulfate exposure is associated with NICU admission among term and late-preterm neonates in a dose-dependent fashion. Fluid and nutritional assistance commonly are needed in this cohort.

Magnesium sulfate normalizes placental interleukin-6 secretion in preeclampsia

Interleukin-6 (IL-6) is one of the main proinflammatory mediators of hypertension and endothelial dysfunction in preeclampsia. In this study, we investigated the capacity of the preeclamptic placenta to secrete IL-6 and the effect of magnesium sulfate (MgSO(4)) on it. Placentas from normotensive (37-40 weeks) and preeclamptic (36-40 weeks) pregnancies were dually perfused for 6 h in the absence [normotensive (n = 3); preeclamptic (n = 4)] and presence [normotensive (n = 3); preeclamptic (n = 4)] of MgSO(4). Perfusate samples from the maternal and the fetal circulations were collected at each 30 min throughout the perfusion period and examined for IL-6 by enzyme-linked immunoassay. Statistical analysis was performed using the 2-way analysis of variance. In the absence of MgSO(4), IL-6 levels in the maternal and the fetal circulations of preeclamptic placentas (4.2 ± 1.3 and 0.9 ± 0.5 pg/mL/g cotyledon; respectively) were significantly higher, when compared with normotensive placentas (1.9 ± 0.5 and 0.2 ± 0.2 pg/mL/g cotyledon; respectively) (P < 0.05). Addition of MgSO(4) to the perfusate of normotensive placentas did not affect IL-6 secretion. However, exposure of preeclamptic placentas to MgSO(4) resulted in decreased IL-6 levels in the maternal circulations (1.7 ± 0.3 pg/mL/g cotyledon), when compared with the control group (P < 0.05). In the fetal circulation, the addition of MgSO(4) resulted only in a nonstatistical significant tendency toward decreased IL-6 levels, when compared with the control group. Our findings indicate that the perfused preeclamptic placenta secretes increased levels of IL-6 into the fetal and the maternal circulations and that MgSO(4) may normalize these increased secreted IL-6 levels.

Magnesium sulfate infusion prevents shivering during transurethral prostatectomy with spinal anesthesia: a randomized, double-blinded, controlled study

STUDY OBJECTIVE

To determine whether magnesium sulfate (MgSO(4)) infusion during surgery reduces shivering during spinal anesthesia.

DESIGN

Double-blinded placebo-controlled, randomized trial.

SETTING

Operation room of a university hospital.

PATIENTS

60 patients, aged 40 to 70 years, scheduled for elective transurethral resection of the prostate (TURP) during spinal anesthesia.

INTERVENTIONS

Subarachnoid anesthesia consisting of hyperbaric bupivacaine three mL 0.5% was injected using a 25-G Quincke spinal needle. Patients received either saline (Group C, n = 30) or MgSO(4) (Group Mg, n = 30). Group Mg received an intravenous (IV) bolus of MgSO(4) 80 mg/kg via syringe pump over a 30-minute period, followed by a two g/hr infusion during the intraoperative period. Group C received an equal volume of saline.

MEASUREMENTS

Motor blockade was evaluated by Bromage motor scale. Sensory block level was assessed by pinprick test. Shivering was assessed after the completion of subarachnoid drug injection. Side effects were recorded.

MAIN RESULTS

Hypothermia was observed in all patients (100%) in Group Mg and in 24 patients (80%) in Group C (P = 0.024). The decrease in core temperature in Group Mg was significantly greater (P < 0.005). Shivering was observed in two patients (6.7%) in Group Mg and 20 patients (66.7%) in Group C (P = 0.0001).

CONCLUSIONS

MgSO(4) infusion in the perioperative period significantly reduced shivering during TURP with spinal anesthesia. MgSO(4) infusion prevents shivering in patients receiving spinal anesthesia but increases the risk of hypothermia.

Role of proteinuria in defining pre-eclampsia: clinical outcomes for women and babies

1. The presence of proteinuria is not essential to the diagnosis of pre-eclampsia under many diagnostic consensus statements. The aim of the present study was to assess maternal and perinatal outcomes after proteinuric pre-eclampsia compared with other non-proteinuric disease presentations. 2. An individual patient data review (n = 670) was undertaken for 2003-2006 at a tertiary referral centre in Sydney (NSW, Australia). Women were diagnosed in accordance with the Australasian Society for the Study of Hypertension in Pregnancy Consensus Statement. Data were analysed with the Chi-squared test, t-tests and non-parametric tests. Statistical significance was set at P < 0.05. 3. The proteinuric cohort had higher systolic and diastolic blood pressure recordings than the non-proteinuric cohort (160/102 and 149/94 mmHg, respectively; P < 0.001), and were also administered magnesium sulphate more frequently (44 vs 22%, respectively; P < 0.001), delivered at earlier gestation (37 vs 38 weeks, respectively; P < 0.001), required operative delivery more frequently (63 vs 48%, respectively; P < 0.001) and received more antihypertensive medications during the antenatal period (72 vs 57%, respectively; P < 0.001). Acute renal failure and acute pulmonary oedema were rare. Four cases of eclampsia all occurred in non-proteinuric women. The perinatal mortality rate was lower for the offspring of women with proteinuric pre-eclampsia compared with offspring of non-proteinuric women (13/1000 and 31/1000, respectively; P = 0.006). 4. The results of the present study indicate that the presence of proteinuria denotes a group of women who have higher antenatal blood pressure, who deliver at earlier gestation and require operative delivery more commonly, although it is not an indicator of other markers of maternal morbidity or perinatal mortality.

The diagnosis and treatment of hypertensive disorders of pregnancy: new findings for antenatal and inpatient care

BACKGROUND

Hypertensive disorders of pregnancy (HDP) are among the leading causes of maternal and fetal morbidity and mortality. New guidelines and findings from clinical trials must be taken into account so that the diagnosis and treatment of HDP can be optimized.

METHODS

Current guidelines, Cochrane reviews, metaanalyses, and randomized, controlled trials were retrieved by a search in PubMed and the Cochrane Library for reports published from 2006 to March 2009. These publications were then analyzed and evaluated for their evidence levels (EL).

RESULTS AND CONCLUSIONS

Aside from hypertension and proteinuria, the definition of preeclampsia (PE) should also take organ dysfunction into account. Important aspects of antenatal care include the following: the early recognition of risk factors, measurement of the uterine arteries in the 1st and 2nd trimesters with Doppler ultrasonography (A diagnostic tool which is now well established), prophylactic oral administration of 100 mg of acetylsalicylic acid daily from the beginning of pregnancy, particularly in high-risk patients (EL I++), and appropriate measurement of blood pressure and urinary protein. Patients should be hospitalized whenever indicated. Therapeutic goals are adequate treatment of hypertension, as well as seizure prophylaxis with magnesium sulphate in severe preeclampsia to prevent maternal cerebrovascular complications (EL I++). If delivery is indicated, it should be performed, regardless of the gestational age (EL IV). Careful monitoring during the puerperium and a general medical review six weeks after delivery are essential. Women with preeclampsia have a significantly elevated long-term risk of developing cardiovascular diseases in later life (EL I++).

Effects of antenatal exposure to magnesium sulfate on neuroprotection and mortality in preterm infants: a meta-analysis

OBJECTIVE

To review the evidence regarding neuroprotective effects of antenatal exposure to magnesium sulfate.

DATA SOURCES

We conducted database searches of MEDLINE, the Cochrane Library and Controlled Trials Register, as well as the ClinicalTrials.gov and International Clinical Trials Register websites. Bibliographies of all relevant articles were reviewed.

METHODS OF STUDY SELECTION

Randomized controlled trials comparing magnesium sulfate with placebo/other treatment in patients at risk of preterm delivery were evaluated for inclusion and methodological quality. The primary outcome was death or cerebral palsy by 18-24 months corrected age. Secondary outcomes were death, cerebral palsy, moderate-severe cerebral palsy, and death or moderate-severe cerebral palsy. Separate analyses were performed according to the gestational age (GA) at randomization (less than 32 to 34 weeks and less than 30 weeks) and for studies in which magnesium sulfate was used exclusively for fetal neuroprotection.

TABULATION, INTEGRATION, AND RESULTS

Five randomized controlled trials were included (5,235 fetuses/infants). When analyzed by GA at randomization, in utero exposure to magnesium sulfate at less than 32-34 weeks did not reduce the rate of death or cerebral palsy (relative risk [RR] 0.92, 95% confidence interval [CI] 0.83-1.03). However, cerebral palsy (RR 0.70, 95% CI 0.55-0.89), moderate-severe cerebral palsy (RR 0.60, 95% CI 0.43-0.84), and death or moderate-severe cerebral palsy were significantly reduced, without an evident increase in the risk of death (RR 1.01, 95% CI 0.89-1.14). Similar results were obtained when the GA at randomization was less than 30 weeks. When only neuroprotection trials (four trials, 4,324 fetuses/infants) are analyzed, in utero exposure to magnesium sulfate additionally reduced the primary outcome of death or cerebral palsy. The number needed to treat to prevent one case of cerebral palsy among those who survive until age 18-24 months is 46 (95% CI 26-187) in infants exposed to magnesium sulfate in utero before 30 weeks, and 56 (95% CI 34-164) in infants exposed to magnesium sulfate in utero before 32 to 34 weeks.

CONCLUSION

Fetal exposure to magnesium sulfate in women at risk of preterm delivery significantly reduces the risk of cerebral palsy without increasing the risk of death.

The state of emergency obstetric care services in Nairobi informal settlements and environs: results from a maternity health facility survey

Background

Maternal mortality in Sub-Saharan Africa remains a challenge with estimates exceeding 1,000 maternal deaths per 100,000 live births in some countries. Successful prevention of maternal deaths hinges on adequate and quality emergency obstetric care. In addition to skilled personnel, there is need for a supportive environment in terms of essential drugs and supplies, equipment, and a referral system. Many household surveys report a reasonably high proportion of women delivering in health facilities. However, the quality and adequacy of facilities and personnel are often not assessed. The three delay model; 1) delay in making the decision to seek care; 2) delay in reaching an appropriate obstetric facility; and 3) delay in receiving appropriate care once at the facility guided this project. This paper examines aspects of the third delay by assessing quality of emergency obstetric care in terms of staffing, skills equipment and supplies.

Methods

We used data from a survey of 25 maternity health facilities within or near two slums in Nairobi that were mentioned by women in a household survey as places that they delivered. Ethical clearance was obtained from the Kenya Medical Research Institute. Permission was also sought from the Ministry of Health and the Medical Officer of Health. Data collection included interviews with the staff in-charge of maternity wards using structured questionnaires. We collected information on staffing levels, obstetric procedures performed, availability of equipment and supplies, referral system and health management information system.

Results

Out of the 25 health facilities, only two met the criteria for comprehensive emergency obstetric care (both located outside the two slums) while the others provided less than basic emergency obstetric care. Lack of obstetric skills, equipment, and supplies hamper many facilities from providing lifesaving emergency obstetric procedures. Accurate estimation of burden of morbidity and mortality was a challenge due to poor and incomplete medical records.

Conclusion

The quality of emergency obstetric care services in Nairobi slums is poor and needs improvement. Specific areas that require attention include supervision, regulation of maternity facilities; and ensuring that basic equipment, supplies, and trained personnel are available in order to handle obstetric complications in both public and private facilities.

Efficacy and vasodilatory benefit of magnesium prophylaxis for protection against spinal cord ischemia

Prevention of paraplegia remains an imperative issue in thoracoabdominal aortic surgery. The aim of this study was to assess the efficacy of a prophylactic magnesium infusion in a rat spinal cord ischemia model and to demonstrate spinal blood flow increase caused by the infusion. The study was conducted in two parts. Firstly, the neuroprotective effect of magnesium was assessed using a rat model with two different ischemic times: 10 min and 14 min. Spinal cord ischemia was induced by occlusion of the descending aorta. Rats in the treatment group were given a 100 mg/kg magnesium sulfate infusion before ischemia. Secondly, relative changes in spinal cord blood flow before and during ischemia were recorded using the laser Doppler flowmetry technique. Changes in blood flow were compared between the magnesium and control groups. Rats pretreated with magnesium showed good overall recovery after both 10 min (incidence of paraplegia 62.5% control vs. 37.5% Mg, n = 8 each) and 14 min (85.7% control vs. 57.1% Mg, n = 7 each) of ischemia, although the differences compared with controls were statistically insignificant. However, the magnesium group showed significantly better neurological performance during the early postischemic period. Comparison of changes in spinal circulation revealed less reduction in blood flow during ischemia in the magnesium-treated group. In conclusion, magnesium may have potential prophylactic benefits during ischemia by exerting a neuroprotective effect through vasodilation of the spinal cord vasculature. To our knowledge, this vasodilatory effect on the spinal cord has not previously been investigated. Optimization of the treatment regimen, however, is required.

Magnesium for seizure prophylaxis in patients with mild preeclampsia

OBJECTIVE

To estimate whether magnesium therapy is the optimal management for women with mild preeclampsia.

METHODS

A decision analytic model was designed for women with mild preeclampsia to estimate whether empiric magnesium therapy or no magnesium therapy is the optimal management strategy. The model considered relevant clinical events: seizure, placental abruption, and magnesium toxicity. Modeled outcomes were maternal mortality, neonatal mortality, and neurologic neonatal compromise. The two strategies were compared based on the probability of clinical events and outcomes and the utilities or values assigned to the outcomes by prior research. Probabilities and utilities were derived from the literature.

RESULTS

The base-case analysis showed that although the no-magnesium strategy results in a 15% reduction in neonatal mortality and avoids most maternal drug toxicity, it produces a twofold increase in maternal death and more neurologically compromised neonates compared with empiric magnesium. The two strategies are essentially equivalent with regard to aggregate maternal and neonatal outcomes (0.9792 compared with 0.9781 utilities). Multivariable sensitivity analysis using Monte Carlo simulation confirmed the decision to be a "toss-up," yielding a similar mean utility for no-magnesium and magnesium strategies (0.9789+/-0.1374 compared with 0.9784+/-0.1390, respectively).

CONCLUSION

Our decision model indicates that either strategy, using or not using empiric magnesium sulfate therapy, is acceptable. The clinical decision of whether to use magnesium in patients with mild preeclampsia for seizure prophylaxis should be determined by the physician or institution, considering patient values or preferences and the unique risk-benefit trade-off of each strategy.

Achieved serum magnesium concentrations and occurrence of delayed cerebral ischaemia and poor outcome in aneurysmal subarachnoid haemorrhage

BACKGROUND

Magnesium therapy probably reduces the frequency of delayed cerebral ischaemia (DCI) in subarachnoid haemorrhage (SAH) but uncertainty remains about the optimal serum magnesium concentration. We assessed the relationship between serum magnesium concentrations achieved with magnesium sulphate therapy 64 mmol/day and the occurrence of DCI and poor outcome in patients with SAH.

METHODS

Differences in magnesium concentrations between patients with and without DCI and with and without poor outcome were calculated. Quartiles of last serum magnesium concentrations before the onset of DCI, or before the median day of DCI in patients without DCI, were related to the occurrence of DCI and poor outcome at 3 months using logistic regression.

RESULTS

Compared with the lowest quartile of serum magnesium concentration (1.10-1.28 mmol/l), the risk of DCI was decreased in each of the higher three quartiles (adjusted odds ratio (OR) in each quartile 0.2; lower 95% CI 0.0 to 0.1; upper limit 0.8 to 0.9). The OR for poor outcome was 1.8 (95% CI 0.5 to 6.9) in the second quartile, 1.0 (95% CI 0.2 to 4.5) in the third quartile and 4.9 (95% CI 1.2 to 19.7) in the highest quartile.

DISCUSSION

Magnesium sulphate 64 mmol/day results in a stable risk reduction of DCI over a broad range of achieved serum magnesium concentrations, and strict titration of the dosage therefore does not seem necessary. However, concentrations < or = 1.28 mmol/l could decrease the effect on DCI while concentrations > or = 1.62 might have a negative effect on clinical outcome.

Cerebral Hemodynamics in Preeclampsia: Cerebral Perfusion and the Rationale for an Alternative to Magnesium Sulfate

Preeclampsia and eclampsia continue to be major causes of maternal death. Currently, approximately 18% of U.S. maternal deaths are attributed to hypertensive disorders and eclampsia, and several hundred women die from eclampsia and its complications every year. In the United States, preeclamptic women have received magnesium sulfate as a seizure prophylaxis agent for 3 decades, and this practice is becoming more widely accepted internationally. In addition to a recognized failure rate, there are financial, logistic, and safety concerns associated with the universal administration of magnesium sulfate. Many institutions in the developing world lack the necessary equipment and expertise to administer the medication, and many preeclamptic patients thus do not receive magnesium sulfate before their first seizure. As effective as it has been in reducing mortality from eclampsia, magnesium sulfate is also associated with appreciable morbidity and mortality from administration errors and magnesium toxicity. The availability of an easily administered, cheap, safe, and orally administered alternative to magnesium sulfate would be welcomed in the developing world and would provide an extremely useful alternative therapy to the current standard of care. Recent advances in the understanding of the pathophysiology of preeclampsia and eclampsia, primarily related to cerebral perfusion and blood flow, could allow us to reduce the seizure rate in treated preeclamptic women even further than what is currently reported. This article deals with the rationale behind the use of labetalol as an alternative to magnesium sulfate for the prevention of eclampsia.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to recall that hypertensive diseases of pregnancy contribute a significant portion of today's maternal mortality, explain that methods of preventing eclampsia are not applicable worldwide, and state that understanding of the pathophysiology of preeclampsia/eclampsia may assist in developing safe and effective medications that can be used universally.

Effect of magnesium sulfate on the calcium-stimulated adenosine triphosphatase activity and lipid peroxidation of red blood cell membranes from preeclamptic women

The effect of the treatment with magnesium sulfate (MgSO(4)) on Ca-ATPase activity and level of lipid peroxidation of red blood cells from preeclamptic pregnant women was examined because it is known that these parameters are affected with preeclampsia. Red cell ghosts from 11 normotensive and 11 preeclamptic pregnant women, before and after treatment with MgSO(4), were assayed for Ca-ATPase activity and level of lipid peroxidation, determined as TBARS or conjugated dienes. It was found that the Ca-ATPase activity is significantly lower and the level of lipid peroxidation is significantly higher in the preeclamptic women with no treatment, as compared to normotensive pregnant women. Both parameters return to normal values after the MgSO(4) therapy. These results can be mimicked by in vitro preincubation with MgSO(4) of intact red blood cells from preeclamptic pregnant women, without any treatment. Our data indicate that MgSO(4) treatment of preeclamptic pregnant women modifies both the Ca-ATPase activity and the level of lipid peroxidation of their red blood cell membranes, reaching values similar to those of normotensive pregnant women. The diminution of the level of lipid peroxidation by MgSO(4), can account for the increase in Ca-ATPase activity.