Does magnesium sulfate affect the length of labor induction in women with pregnancy-associated hypertension?

Preeclampsia: Pathogenesis, Prevention, and Long-Term Complications

Preeclampsia continues to afflict 5% to 8% of all pregnancies throughout the world and is associated with significant morbidity and mortality to the mother and the fetus. Although the pathogenesis of the disorder has not yet been fully elucidated, current evidence suggests that imbalance in angiogenic factors is responsible for the clinical manifestations of the disorder, and may explain why certain populations are risk. In this review, we begin by demonstrating the roles that angiogenic factors play in pathogenesis of preeclampsia and its complications in the mother and the fetus. We then continue to report on the use of angiogenic markers as biomarkers to predict and risk-stratify disease. Strategies to treat preeclampsia by correcting the angiogenic balance, either by promoting proangiogenic factors or by removing antiangiogenic factors in both animal and human studies, are discussed. We end the review by summarizing status of the current preventive strategies and the long-term cardiovascular outcomes of women afflicted with preeclampsia.

Inadequate safety reporting in pre-eclampsia trials: a systematic evaluation

BACKGROUND

Randomised trials and their syntheses in meta-analyses offer a unique opportunity to assess the frequency and severity of adverse reactions.

OBJECTIVE

To assess safety reporting in pre-eclampsia trials.

SEARCH STRATEGY

Systematic search using bibliographic databases, including Cochrane Central Register of Controlled Trials, Embase, and MEDLINE, from inception to August 2017.

SELECTION CRITERIA

Randomised trials evaluating anticonvulsant or antihypertensive medication for pre-eclampsia.

DATA COLLECTION AND ANALYSIS

Descriptive statistics appraising the adequacy of adverse reaction and toxicity reporting.

MAIN RESULTS

We included 60 randomised trials. Six trials (10%) were registered with the International Clinical Trials Registry Platform, two registry records referred to adverse reactions, stating 'safety and toleration' and 'possible side effects' would be collected. Twenty-six trials (43%) stated the frequency of withdrawals within each study arm, and five trials (8%) adequately reported these withdrawals. Adverse reactions were inconsistently reported across eligible trials: 24 (40%) reported no serious adverse reactions and 36 (60%) reported no mild adverse reactions. The methods of definition or measurement of adverse reactions were infrequently reported within published trial reports.

CONCLUSIONS

Pre-eclampsia trials regularly omit critical information related to safety. Despite the paucity of reporting, randomised trials collect an enormous amount of safety data. Developing and implementing a minimum data set could help to improve safety reporting, permitting a more balanced assessment of interventions by considering the trade-off between the benefits and harms.

FUNDING

National Institute for Health Research (DRF-2014-07-051), UK; Maternity Forum, Royal Society of Medicine, UK.

TWEETABLE ABSTRACT

Developing @coreoutcomes could help to improve safety reporting in #preeclampsia trials. @NIHR_DC.

Magnesium in obstetric anesthesia and intensive care

Magnesium, one of the essential elements in the human body, has numerous favorable effects that offer a variety of possibilities for its use in obstetric anesthesia and intensive care. Administered as a single intravenous bolus dose or a bolus followed by continuous infusion during surgery, magnesium attenuates stress response to endotracheal intubation, and reduces intraoperative anesthetic and postoperative analgesic requirements, while at the same time preserving favorable hemodynamics. Applied as part of an intrathecal or epidural anesthetic mixture, magnesium prolongs the duration of anesthesia and diminishes total postoperative analgesic consumption with no adverse maternal or neonatal effects. In obstetric intensive care, magnesium represents a first-choice medication in the treatment and prevention of eclamptic seizures. If used in recommended doses with close monitoring, magnesium is a safe and effective medication.

Magnesium sulphate versus phenytoin in eclampsia - Maternal and foetal outcome - A comparative study

BACKGROUND

Eclampsia manifests as seizures and is unique to the pregnant state. It remains an important cause of maternal mortality especially in resource-challenged countries that lack access to prenatal care.

AIMS

The aim of our study was to compare maternal and foetal outcomes in mothers with eclampsia with the administration of either magnesium sulphate or phenytoin in a resource- challenged situation.

METHOD

The work was conducted from January 2012 to December 2012. A total of 80 patients were assigned alternately to two groups - one group was treated with magnesium sulphate (Group-M; n=40), and the other treated with phenytoin (Group-P; n=40) (Figure 1). The magnesium sulphate was administered according to Pritchard's regimen; phenytoin administered according to Ryan's regimen. With either regimen, anticonvulsant therapy was continued for 24 hours postpartum or 24 hours after the last convulsion, whichever was later.

RESULTS

Fifty-four per cent of patients regained consciousness within eight hours of treatment onset in Group-P compared to 5.3 per cent in Group-M (p=0.0001, χ(2)=19.24). Seven patients in Group-P had recurrence of convulsions as compared to none of the 40 women assigned to Group-M (p=0.032, χ(2)=4.62). The incidence of Caesarean section was greater (62.5 per cent) in Group-M compared to Group-P (25 per cent; p=0.001, χ(2)= 9.96). No statistically significant differences were found in the foetal outcomes between the two groups.

CONCLUSION

Phenytoin use may be reconsidered in selective cases in low and middle income countries (LMIC) as it has been found simpler to use, has several benefits and also curtails treatment cost. Magnesium sulphate is substantially more effective than phenytoin with regard to recurrence of convulsions. Proper training in the management of eclampsia should be given to all health care workers to ensure appropriate management of eclamptic mothers. Thus, the treatment of this disease calls for more research especially in resource-challenged settings.

Eclampsia characteristics and outcomes: a comparison of two eras

Objective. To describe the trends in incidence, characteristics, and outcomes of women with eclampsia. Methods. We reviewed and abstracted data from medical records of all women diagnosed with eclampsia in our institution from August 1998 to April 2011. In addition to overall characteristics and outcomes, the cases were stratified by onset: antenatal versus postnatal and early (<32 weeks of gestation) versus late antenatal cases (≥32 weeks of gestation). Comparisons were made using chi-square, Fisher's exact, Mann-Whitney U, and t-tests. A two-sided P < 0.05 was considered statistically significant. Results. We identified 87 eclampsia cases out of 59,388 deliveries; 62 cases were diagnosed before delivery, and 25 had a postnatal onset. Among the 62 antenatal cases, 41 were diagnosed before 32 weeks and 21 at or after 32 weeks of gestation. Antenatal cases had higher systolic (P = 0.03) and diastolic (P = 0.01) blood pressures, more abnormal dipstick-test proteinuria (P = 0.002), and lower platelet counts (P ≤ 0.001) than postnatal cases. Early eclampsia cases were complicated more often with HELLP syndrome than late eclampsia cases (P = 0.007). Conclusion. The occurrence of eclampsia has decreased over time. The earlier the onset is, the worse the outcome appears to be.

Magnesium sulphate and other anticonvulsants for women with pre-eclampsia

BACKGROUND

Eclampsia, the occurrence of a seizure (fit) in association with pre-eclampsia, is rare but potentially life-threatening. Magnesium sulphate is the drug of choice for treating eclampsia. This review assesses its use for preventing eclampsia.

OBJECTIVES

To assess the effects of magnesium sulphate, and other anticonvulsants, for prevention of eclampsia.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (4 June 2010), and the Cochrane Central Register of Controlled Trials Register (The Cochrane Library 2010, Issue 3).

SELECTION CRITERIA

Randomised trials comparing anticonvulsants with placebo or no anticonvulsant, or comparisons of different drugs, for pre-eclampsia.

DATA COLLECTION AND ANALYSIS

Two authors assessed trial quality and extracted data independently.

MAIN RESULTS

We included 15 trials. Six (11,444 women) compared magnesium sulphate with placebo or no anticonvulsant: magnesium sulphate more than a halved the risk of eclampsia (risk ratio (RR) 0.41, 95% confidence interval (CI) 0.29 to 0.58; number needed to treat for an additional beneficial outcome (NNTB) 100, 95% CI 50 to 100), with a non-significant reduction in maternal death (RR 0.54, 95% CI 0.26 to 1.10) but no clear difference in serious maternal morbidity (RR 1.08, 95% CI 0.89 to 1.32). It reduced the risk of placental abruption (RR 0.64, 95% CI 0.50 to 0.83; NNTB 100, 95% CI 50 to 1000), and increased caesarean section (RR 1.05, 95% CI 1.01 to 1.10). There was no clear difference in stillbirth or neonatal death (RR 1.04, 95% CI 0.93 to 1.15). Side effects, primarily flushing, were more common with magnesium sulphate (24% versus 5%; RR 5.26, 95% CI 4.59 to 6.03; number need to treat for an additional harmful outcome (NNTH) 6, 95% CI 5 to 6).Follow-up was reported by one trial comparing magnesium sulphate with placebo: for 3375 women there was no clear difference in death (RR 1.79, 95% CI 0.71 to 4.53) or morbidity potentially related to pre-eclampsia (RR 0.84, 95% CI 0.55 to 1.26) (median follow-up 26 months); for 3283 children exposed in utero there was no clear difference in death (RR 1.02, 95% CI 0.57 to 1.84) or neurosensory disability (RR 0.77, 95% CI 0.38 to 1.58) at age 18 months.Magnesium sulphate reduced eclampsia compared to phenytoin (three trials, 2291 women; RR 0.08, 95% CI 0.01 to 0.60) and nimodipine (one trial, 1650 women; RR 0.33, 95% CI 0.14 to 0.77).

AUTHORS' CONCLUSIONS

Magnesium sulphate more than halves the risk of eclampsia, and probably reduces maternal death. There is no clear effect on outcome after discharge from hospital. A quarter of women report side effects with magnesium sulphate.

Magnesium in obstetrics

Magnesium is a critical physiological ion, and magnesium deficiency might contribute to the development of pre-eclampsia, to impaired neonatal development and to metabolic problems extending into adult life. Pharmacologically, magnesium is a calcium antagonist with substantial vasodilator properties but without myocardial depression. Cardiac output usually increases following magnesium administration, compensating for the vasodilatation and minimising hypotension. Neurologically, the inhibition of calcium channels and antagonism of the N-methyl-d-aspartic acid (NMDA) receptor raises the possibility of neuronal protection, and magnesium administration to women with premature labour may decrease the incidence of cerebral palsy. It is the first-line anticonvulsant for the management of pre-eclampsia and eclampsia, and it should be administered to all patients with severe pre-eclampsia or eclampsia. Magnesium is a moderate tocolytic but the evidence for its effectiveness remains disputed. The side effects of magnesium therapy are generally mild but the major hazard of magnesium therapy is neuromuscular weakness.

Magnesium sulphate given before very-preterm birth to protect infant brain: the randomised controlled PREMAG trial*

OBJECTIVE

To evaluate whether magnesium sulphate (MgSO(4)) given to women at risk of very-preterm birth would be neuroprotective in preterm newborns and would prevent neonatal mortality and severe white-matter injury (WMI).

DESIGN

A randomised study.

SETTING

Eighteen French tertiary hospitals. Population Women with fetuses of gestational age < 33 weeks whose birth was planned or expected within 24 hours were enrolled from July 1997 to July 2003 with follow up of infants until hospital discharge. METHODS Five hundred and seventy-three mothers were randomly assigned to receive a single 40-ml infusion of 0.1 g/ml of MgSO(4) (4 g) solution or isotonic 0.9% saline (placebo) over 30 minutes. This study is registered as an International Standard Randomised Controlled Trial, number 00120588.

MAIN OUTCOME MEASURES

The primary endpoints were rates of severe WMI or total mortality before hospital discharge, and their combined outcome. Analyses were based on intention to treat.

RESULTS

After 6 years of enrolment, the trial was stopped. Data from 688 infants were analysed. Comparing infants who received MgSO(4) or placebo, respectively, total mortality (9.4 versus 10.4%; OR: 0.79, 95% CI 0.44-1.44), severe WMI (10.0 versus 11.7%; OR: 0.78, 95% CI 0.47-1.31) and their combined outcomes (16.5 versus 17.9%; OR: 0.86, 95% CI 0.55-1.34) were less frequent for the former, but these differences were not statistically significant. No major maternal adverse effects were observed in the MgSO(4) group.

CONCLUSION

Although our results are inconclusive, improvements of neonatal outcome obtained with MgSO(4) are of potential clinical significance. More research is needed to assess the protective effect of MgSO(4) alone or in combination with other neuroprotective molecules.

Does continuing oral magnesium supplementation until delivery affect labor and puerperium outcome?

OBJECTIVE

To determine the labor and puerperal impact of continuing oral magnesium supplementation until delivery.

STUDY DESIGN

Single-center study with matched controls. In 40 pairs of healthy women with vaginally delivered singleton pregnancies, matched for maternal age, race and parity, maternal and neonatal outcome endpoints were compared in those receiving continuous oral magnesium aspartate supplementation 15-30 mmol/d for at least 4 weeks until delivery (for constipation, calf cramps, preterm contraction without cervical effacement or additional tocolytics) versus non-supplemented controls.

RESULTS

In the magnesium group labor was nonsignificantly longer (stage 1: 326.0+/-187.5 min versus 276.7+/-140.8 min, P = 0.19; stage 2: 52.0+/-44.5 min versus 43.5+/-44.0 min, P = 0.40) and maximum oxytocin dose nonsignificantly higher (14.5+/-9.4 [median 12.0; n=15] versus 10.5+/-6.9 [median 7.5] mU/min, P = 0.28; n = 10). Fewer women had afterpains (12 versus 20, P=0.11), required spasmolysis (3 versus 14, P = 0.005), or could breastfeed their infants exclusively at discharge (24 versus 34, P = 0.04).

CONCLUSION

Continuing oral magnesium supplementation until delivery does not significantly prolong labor or increase the oxytocin requirement, but it significantly impairs breastfeeding competence.

Effect of Preeclampsia, Magnesium Sulfate Prophylaxis, and Maternal Weight on Labor Induction: A Retrospective Analysis

BACKGROUND

Our purposes were to determine the effect of preeclampsia, magnesium sulfate prophylaxis, and maternal weight on labor induction in women with preeclampsia and identify risk factors associated with its failure.

METHODS

Fifty-five preeclamptic women and 176 non-preeclamptic women requiring labor induction over an 18-month period were studied retrospectively. Prostaglandin E(2) (dinoprostone) and oxytocin were used for labor induction. Women with rupture of the membranes, spontaneous contraction resulting in cervical change, or an initial cervical examination showing more than 2 cm dilatation and 50% effacement were excluded. Statistics were analyzed with chi(2) test, Fisher's exact test, Student t test, Mann-Whitney U test, and multiple logistic regression.

RESULTS

The women with preeclampsia had a significantly higher rate of failed induction than did those without preeclampsia (p = 0.01). However, the women with preeclampsia had a higher mean maternal weight and an increased use of magnesium sulfate, and labor was induced at earlier gestational age than in those without preeclampsia (p < 0.05 for each). Multiple logistic regression showed that the use of magnesium sulfate, higher maternal weight, and unfavorable cervix, but not preeclampsia, were significantly associated with an increased risk of failed induction after correction for known confounding variables.

CONCLUSIONS

Although the risk of failed induction is increased in preeclamptic women, preeclampsia is not an independent risk factor for failed induction. The use of magnesium sulfate, higher maternal weight, and unfavorable cervix are independent risk factors for failed induction.

Mode of delivery in pregnant women with hypertensive disorders and unfavorable cervix following induction of labor with vaginal application of prostaglandin E

BACKGROUND

Our aim was to evaluate the mode of delivery in pregnant women with hypertensive disorders and unfavorable cervix following induction of labor with vaginal application of prostaglandin E(2) (PGE(2)) near or at term, and to define the predictors of successful vaginal delivery in such women.

METHODS

In a retrospective case-controlled study, pregnant women with hypertension, who underwent labor induction with PGE(2) tablets (study group, n = 284), were compared with women, who underwent elective induction of labor (group 2, n = 115), and women with normal spontaneous onset of labor (group 3, n = 510).

RESULTS

The rate of cesarean section (CS) was significantly higher in the study group (25.3%) than in group 2 (14.8%) and in group 3 (9%). Exclusion of the nulliparous women from the study and control groups yielded similar CS rates in the study group (16.9%) and in group 2 (11.1%). Women with pre-eclampsia and the women with chronic hypertension or pregnancy-induced hypertension had similar rates of CS. In logistic regression model, nulliparity, induction of labor with PGE(2), and maternal age, but not hypertensive disorders, were independently and significantly associated with increased risk of CS.

CONCLUSIONS

PGE(2) induction of labor is successful in approximately 75% of patients with hypertensive disorders and unfavorable cervix, with apparently no serious maternal or fetal complications. The induction of labor by itself, and not the hypertensive disorders in pregnancy, is independent risk factor for CS.

Evidence and practice: the magnesium sulphate story

There is now strong evidence from systematic reviews of randomised trials to support the use of magnesium sulphate for the prevention and treatment of eclampsia. Magnesium sulphate more than halves the risk of eclampsia for women with pre-eclampsia (relative risk (RR) 0.41, 95% confidence interval (CI) 0.29-0.58; number needed to treat (NNT) 102 (95% CI 72-173) compared to placebo. For treatment of eclampsia, magnesium sulphate lowers the risk of maternal death (RR 0.59, 95% CI 0.37-0.94) and of recurrence of further fits (RR 0.44, 95% CI 0.34-0.57) compared to diazepam. Magnesium sulphate also reduces the risk of further fits compared to phenytoin (RR 0.31, 95% CI 0.20-0.47) and to lytic cocktail (RR 0.09, 95% CI 0.03-0.24).

Prostaglandin: cervical ripening in hypertensive pregnancies

BACKGROUND

To determine the outcome of cervical ripening with intracervical prostaglandin E2 (PEG2) in hypertensive and non-hypertensive high-risk pregnancies in terms of successful ripening, mode of delivery, time intercorring between ripening and the beginning of labor or parturition and, at least, duration of labor.

METHODS

A total of 63 women with a diagnosis of hypertensive disorders were included in the study protocol. These 63 women were compared with 71 consecutive high-risk pregnancies requiring induction of labor for maternal and/or fetal indications. Cervical ripening was performed with single or multiple doses of 0.5 mg of intracervical PGE2 gel.

RESULTS

The rate of successful ripening was 84% for non-hypertensive patients (60/71) and 69% (43/63) for hypertensive patients ( p < 0.03). Twenty-four out of 63 hypertensive patients (38%) and 21 out of 71 non-hypertensive patients (30%) ( p < 0.05) were delivered by cesarean section. After stratification of hypertensive patients, the time interval from the first PGE2 administration to the onset of labor or vaginal delivery was significantly longer for preeclamptic patients vs. non-hypertensive patients or non-preeclamptic hypertensive patients. There were no differences in the duration of labor.

CONCLUSIONS

Among hypertensive patients, only preeclamptic patients showed a lower rate of successful ripening and vaginal delivery if compared with non-preeclamptic or non-hypertensive patients; however, a vaginal delivery might be obtained in most preeclamptic patients when suitable cervical ripening was performed in the presence of clinician-perceived urgency to delivery.

Magnesium sulphate and other anticonvulsants for women with pre-eclampsia

BACKGROUND

Pre-eclampsia is a relatively common complication of pregnancy. Eclampsia, the occurrence of one or more convulsions (fits) in association with the syndrome of pre-eclampsia, is a rare but serious complication. Anticonvulsants are used in the belief they help prevent eclamptic fits and so improve outcome.

OBJECTIVES

The objective was to assess the effects of anticonvulsants for pre-eclampsia on the women and their children.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (28 November 2002), and the Cochrane Controlled Trials Register (The Cochrane Library, Issue 3, 2002).

SELECTION CRITERIA

Randomised trials comparing anticonvulsants with placebo or no anticonvulsants or comparisons of different anticonvulsants in women with pre-eclampsia.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trial quality and extracted data independently.

MAIN RESULTS

Six trials (11,444 women) compared magnesium sulphate with placebo or no anticonvulsant. There was more than a halving in the risk of eclampsia associated with magnesium sulphate (relative risk (RR) 0.41, 95% confidence interval (CI) 0.29 to 0.58; number needed to treat (NNT) 100, 95% CI 50 to 100). The risk of dying was non-significantly reduced by 46% for women allocated magnesium sulphate (RR 0.54, 95% CI 0.26 to 1.10). For serious maternal morbidity RR 1.08, 95% CI 0.89 to 1.32. Side effects were more common with magnesium sulphate (24% versus 5%; RR 5.26, 95% CI 4.59 to 6.03; NNT for harm 6, 95% CI 6 to 5). The main side effect was flushing. Risk of placental abruption was reduced for women allocated magnesium sulphate (RR 0.64, 95% CI 0.50 to 0.83; NNT 100, 95% CI 50 to 1000). Women allocated magnesium sulphate had a small increase (5%) in the risk of caesarean section (95% CI 1% to 10%). There was no overall difference in the risk of stillbirth or neonatal death (RR 1.04, 95% CI 0.93 to 1.15). Magnesium sulphate was better than phenytoin for reducing the risk of eclampsia (two trials 2241 women; RR 0.05, 95% CI 0.00 to 0.84), but with an increased risk of caesarean section (RR 1.21, 95% CI 1.05 to 1.41). It was also better than nimodipine (1 trial, 1650 women; RR 0.33, 95% CI 0.14 to 0.77).

REVIEWER'S CONCLUSIONS

Magnesium sulphate more than halves the risk of eclampsia, and probably reduces the risk of maternal death. It does not improve outcome for the baby, in the short term. A quarter of women have side effects, particularly flushing.

Management of hypertension in pregnancy

Hypertension is an important cause of both maternal and fetal morbidity and mortality in pregnant women. There are still no definitive guidelines as to when and how patients should be treated, but it is important that appropriate treatment is initiated early in patients at highest risk and they are closely monitored. Hypertension in pregnancy can be a difficult condition to diagnose and treat because of the numerous and differing classification systems that have been used in the past. One classification system, which accounts for the multisystem involvement which can occur in pre-eclampsia and eclampsia, divides hypertension in pregnancy into 3 main groups: pre-eclampsia, gestational hypertension and chronic hypertension. Little benefit to the fetus has been shown from treating gestational and chronic hypertension, but studies in this area have been small and would not have had the power to show a difference in outcome between treated and untreated groups. However, the reduction in morbidity and mortality in the treatment of pre-eclampsia is significant. Therefore, all pregnancies complicated by hypertension require monitoring to detect the possible onset of superimposed pre-eclampsia/eclampsia. Institutions should have a management strategy for those mothers with severe hypertension including a multidisciplinary approach, where the patient is to be monitored and which antihypertensive agents are to be used. It should not be forgotten that the definitive treatment for severe hypertension is delivery of the fetus despite risks to fetal morbidity and mortality. This will reduce blood pressure, but hypertension per se may still persist post partum requiring short term therapy.

Preeclampsia into eclampsia: toward a new paradigm

OBJECTIVE

This study was undertaken to characterize aspects of the natural history of eclampsia.

STUDY DESIGN

A retrospective analysis was performed on the records of patients with eclampsia who were delivered at two tertiary care hospitals.

RESULTS

Fifty-three pregnancies complicated by eclampsia were identified. Thirty-seven of the women were nulliparous. The mean age was 22 years (range, 15-38 years). Mean gestational age at the time of seizures was 34.2 weeks' gestation (range, 22-43 weeks' gestation). Twenty-eight women had antepartum seizures (53%); 23 of the 28 had seizures at home. Nineteen women had intrapartum seizures (36%). Eight of these women had seizures while receiving magnesium sulfate, and 7 had therapeutic magnesium levels. Six women had postpartum seizures (11%), 4 >24 hours after delivery. Headache preceded seizures in 34 cases. Visual disturbance preceded seizures in 16 cases. The uric acid level was elevated to >6 mg/dL in 43 women. There were no maternal deaths or permanent morbidities. There were 4 perinatal deaths. Two patients had intrauterine fetal deaths at 28 and 36 weeks' gestation. These mothers had seizures at home. One infant died of complications of prematurity at 22 weeks' gestation and one died of respiratory complications at 26 weeks' gestation. There were 4 cases of abruptio placentae, 1 of which resulted in fetal death. Of the 53 cases of eclampsia, only 9 were potentially preventable. One of these was that of a woman who was being observed at home. The other 8 women were hospitalized and had hypertension and proteinuria. Only 7 women could be considered to have severe preeclampsia before seizure (13%), and 4 of these 7 women were receiving magnesium sulfate.

CONCLUSIONS

Eclampsia was not found to be a progression from severe preeclampsia. In 32 of 53 cases (60%) seizures were the first signs of preeclampsia. In this series eclampsia appeared to be more of a subset of preeclampsia. Only 9 cases of eclampsia were potentially preventable with current standards of practice. Our paradigm for this disease, as well as our approach to seizure prophylaxis, should be reevaluated.

Anesthetic management of preeclampsia/eclampsia

Preeclampsia/eclampsia affects only a small proportion of all pregnancies, yet accounts for much of the obstetric morbidity and mortality seen in the USA and UK. A full understanding of preeclampsia/eclampsia, its variable presentation and complex pathophysiology allows the consulting anesthesiologist to optimize a plan for anesthetic management of the afflicted patient.

Pre-eclampsia and induction of labor: a randomized comparison of prostaglandin E2 as an intracervical gel, with oxytocin immediately, or as a sustained-release vaginal insert

OBJECTIVE

Our purpose was to compare the efficacy of commercial prostaglandin E2 products, in combination with oxytocin, for the initiation of labor among pregnancies with pre-eclampsia.

STUDY DESIGN

Patients with pregnancy-induced hypertension and with either proteinuria or other end-organ damage were enrolled if they had an unfavorable Bishop score (</=4) and were eligible to undergo labor. Each was randomly assigned to receive prostaglandin E2 either as a 0. 5-mg intracervical gel (Prepidil) or as a 10-mg controlled-release vaginal insert (Cervidil). Oxytocin was begun either immediately after instillation of the gel or was delayed until after removal of the insert.

RESULTS

Of the 70 patients, there were no differences between the Prepidil (n = 34) and the Cervidil (n = 36) groups in maternal demographics, gestational age, parity, and predose Bishop score. There was a mean 14.3-hour difference in the duration from beginning therapy until vaginal delivery in the Prepidil group than in the Cervidil group (11.5 +/- 2.3 hours vs 25.8 +/- 6.9 hours, P <. 001). This time difference, which favored use of Prepidil-immediate oxytocin, remained significant after parity (nulliparous: 20 hours, P <.005; multiparous: 12 hours, P <.01) and gestational age were controlled (preterm: 15.5 hours, P <.01; term: 13.3 hours, P <.01).

CONCLUSION

Use of combined intracervical prostaglandin E2 gel-immediate oxytocin therapy was more effective in shortening the induction-to-vaginal delivery time than use of a controlled-release prostaglandin E2 vaginal insert.

Effectiveness of prostaglandin E2 intracervical gel (Prepidil), with immediate oxytocin, versus vaginal insert (Cervidil) for induction of labor

OBJECTIVE

Our purpose was to compare the effectiveness of labor induction with use of prostaglandin E2 either as an intracervical gel (Prepidil), with immediate oxytocin, or as a sustained-release vaginal insert (Cervidil) with subsequent oxytocin as needed.

STUDY DESIGN

Hospitalized patients at >/=37 weeks' gestation requiring labor induction and having an unfavorable cervix (Bishop score </=6) were randomly assigned to receive either Prepidil or Cervidil. Oxytocin was begun immediately after Prepidil placement or 30 minutes after removal of the Cervidil insert if needed.

RESULTS

Of the 150 patients, there were no differences in demographics and eventual pregnancy outcomes between the Prepidil group (n = 77) and the Cervidil group (n = 73). Those pregnancies receiving the Prepidil-immediate oxytocin regimen were delivered sooner than those receiving the Cervidil among nulliparous (11.3 +/- 7.3 hours vs 25.2 +/- 12.5 hours, P <.001) and multiparous (8.4 +/- 7.8 hours vs 18.4 +/- 7.2 hours, P <.001) women. The mean cost savings, which favored the Prepidil-immediate oxytocin regimen, was $458 (range $204 to $630) per patient.

CONCLUSION

Compared with Cervidil, the Prepidil-immediate oxytocin regimen resulted in a shorter induction-to-vaginal delivery interval and in more hospital cost savings without increasing adverse outcomes.

Does magnesium sulfate given for prevention of eclampsia affect the outcome of labor?

OBJECTIVE

The purpose of this study was to determine whether magnesium sulfate given for prevention of eclampsia affected labor outcomes compared with phenytoin, which is not known to impede uterine activity when given in anticonvulsant doses.

STUDY DESIGN

Secondary analysis was performed of a study of women with pregnancy-induced hypertension who were admitted for delivery and randomly assigned to receive either magnesium sulfate or phenytoin for eclampsia prophylaxis. Nulliparous women with a singleton pregnancy in cephalic presentation at term were selected for analysis in an effort to limit the influence of confounding variables such as preterm birth and malpresentations on labor management and outcomes. Similarly, women who had severe preeclampsia and who received labor epidural analgesia were excluded.

RESULTS

A total of 2138 women were randomized to receive magnesium sulfate or phenytoin in the primary study. A total of 905 nulliparous women met the inclusion criteria for this secondary analysis; 480 had been randomized to phenytoin and 425 were given magnesium sulfate. The two groups were similar demographically. Labor outcomes such as (1) oxytocin stimulation, (2) admission-to-delivery intervals, (3) prolonged second-stage labor, (4) forceps delivery, and (5) cesarean delivery were not affected by maternal treatment with magnesium sulfate.

CONCLUSION

Compared with phenytoin, magnesium sulfate given for intrapartum treatment of pregnancy-induced hypertension does not significantly affect labor outcomes.

Seizure prophylaxis in hypertensive pregnancies: a framework for making clinical decisions

OBJECTIVE

To describe a framework for generating therapeutic recommendations using seizure prophylaxis in hypertensive pregnancies as an example.

DESIGN

A decision-making framework was built using: 1. evidence of therapeutic benefit, with number needed to treat as the effect measure; 2. baseline rates of the target disorder that the treatment was designed to prevent; and 3. a treatment threshold, determined by weighting the potential risks against the potential benefits of the treatment.

METHODS

Evidence of therapeutic benefit (i.e. reduction in eclamptic seizures associated with magnesium sulphate therapy in hypertensive pregnancies) was determined by a systematic quantitative overview of controlled clinical trials. Baseline rates of seizures without magnesium sulphate therapy were derived from a recent cohort study. A treatment threshold was generated using estimates of treatment associated morbidities which were weighted against the potential reduction in seizures from magnesium sulphate therapy considering the relative values assigned to these outcomes by obstetricians practising in our hospital.

RESULTS

The number of hypertensive women needed to be treated with magnesium sulphate to prevent a single case of eclamptic seizures varied in a curvilinear fashion dropping from 1000 to 14 as the baseline rate of seizures increased from 0.1% to 10%. The treatment threshold as measured by number needed to treat was 64 (range 57-77). The number needed to treat for nonproteinuric hypertension was 1000 (95% CI 180-40,000), whereas it was 32 (95% CI 20-57) for proteinuric hypertension. Considering the uncertainty in estimation of the numbers needed to treat and treatment threshold, magnesium sulphate therapy may be recommended for women at high risk of eclampsia (e.g. severe pre-eclampsia) while it should be withheld in cases at low risk (e.g. nonproteinuric hypertension and mild pre-eclampsia).

CONCLUSION

While awaiting further research obstetricians intuitively make decisions about seizure prophylaxis in hypertensive pregnancies. Our decision-making framework generated therapeutic recommendations by explicit consideration of the available evidence.

Preeclampsia, labor duration and mode of delivery

OBJECTIVE

To determine if there is a difference in the length of labor, and method of delivery between preeclamptic and normotensive patients.

METHODS

A retrospective case control study was performed using a perinatal database. Study subjects included nulliparous patients diagnosed with preeclampsia, and were compared with normotensive nulliparous patients.

RESULTS

There were 1454 controls and 727 subjects identified. There was no difference between groups with regard to duration of total labor. There was a statistically but not clinically significant increase in the duration of the second stage in preeclamptics (35 vs. 27 min, P = 0.003). Preeclamptics had a consistently higher risk of cesarean delivery, even when controlled for confounding variables.

CONCLUSION

The clinical belief that preeclamptic patients have more rapid labors is not supported. Preeclamptics do seem to have a higher risk of cesarean delivery.

The effect of magnesium sulfate therapy on the duration of labor in women with mild preeclampsia at term: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

The primary outcome was to determine whether magnesium sulfate therapy prolongs the duration of labor in women with mild preeclampsia. Secondary outcomes were to assess the side effects associated with magnesium sulfate therapy: hours and maximum dose of oxytocin, incidence of progression to severe preeclampsia, incidence of cesarean delivery, change in maternal hematocrit, incidence of postpartum hemorrhage, incidence of maternal infection, and Apgar scores.

STUDY DESIGN

Women with a diagnosis of mild preeclampsia at term were randomized to receive standard therapy during labor and for 12 hours post partum with either magnesium sulfate (n = 67) or a matching placebo solution (n = 68).

RESULTS

There was no difference between magnesium sulfate and placebo with respect to the primary outcome variables: total length of labor (median 17.8 hours vs 16.5 hours, p = 0.7) and length of the active phase of labor (median 5.4 hours vs 6.0 hours, p = 0.5). In addition, no difference was observed in the secondary outcome variables: hours of oxytocin use, change in hematocrit, frequency of maternal infection, progression to severe preeclampsia, incidence of cesarean delivery, and Apgar scores. Although not statistically significant, the incidence of postpartum hemorrhage was approximately fourfold greater in the magnesium sulfate group (relative risk 4.1, 95% confidence interval 0.5 to 35.4). There was a significant difference in the maximum dose of oxytocin used (13.9 +/- 8.6 mU/min with magnesium sulfate vs 11.0 +/- 7.6 mU/min with placebo, p = 0.036).

CONCLUSION

The use of magnesium sulfate during labor in women with mild preeclampsia at term does not affect any component of labor but did necessitate a higher dose of oxytocin.