Magnesium sulfate for tocolysis and risk of spastic cerebral palsy in premature children born to women without preeclampsia

No. 376-Magnesium Sulphate for Fetal Neuroprotection

OBJECTIVE

The objective is to provide guidelines for the use of antenatal magnesium sulphate for fetal neuroprotection of the preterm infant.

OPTIONS

Antenatal magnesium sulphate administration should be considered for fetal neuroprotection when women present at ≤33 + 6 weeks with imminent preterm birth, defined as a high likelihood of birth because of active labour with cervical dilatation ≥4 cm, with or without preterm pre-labour rupture of membranes, and/or planned preterm birth for fetal or maternal indications. There are no other known fetal neuroprotective agents.

OUTCOMES

The outcomes measured are the incidence of cerebral palsy (CP) and neonatal death.

EVIDENCE

Published literature was retrieved through searches of PubMed or Medline, CINAHL, and the Cochrane Library in December 2017, using appropriate controlled vocabulary and key words (magnesium sulphate, cerebral palsy, preterm birth). Results were restricted to systematic reviews, randomized controlled trials, and relevant observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to December 2017. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1).

BENEFITS, HARMS, AND COSTS

Antenatal magnesium sulphate for fetal neuroprotection reduces the risk of "death or CP" (relative risk [RR] 0.85; 95% confidence interval [CI] 0.74-0.98; 4 trials, 4446 infants), "death or moderate-severe CP" (RR 0.85; 95% CI 0.73-0.99; 3 trials, 4250 infants), "any CP" (RR 0.71; 95% CI 0.55-0.91; 4, trials, 4446 infants), "moderate-to-severe CP" (RR 0.60; 95% CI 0.43-0.84; 3 trials, 4250 infants), and "substantial gross motor dysfunction" (inability to walk without assistance) (RR 0.60; 95% CI 0.43-0.83; 3 trials, 4287 women) at 2 years of age. Results were consistent between trials and across the meta-analyses. There is no anticipated significant increase in health care-related costs because women eligible to receive antenatal magnesium sulphate will be judged to have imminent preterm birth.

VALIDATION

Australian National Clinical Practice Guidelines were published in March 2010 by the Antenatal Magnesium Sulphate for Neuroprotection Guideline Development Panel. Antenatal magnesium sulphate was recommended for fetal neuroprotection in the same dosage as recommended in these guidelines. However, magnesium sulphate was recommended only at <30 weeks gestation, based on 2 considerations. First, no single gestational age subgroup was considered to show a clear benefit. Second, in the face of uncertainty, the committee felt it was prudent to limit the impact of their clinical practice guidelines on resource allocation. In March 2010, the American College of Obstetricians and Gynecologists issued a Committee Opinion on magnesium sulphate for fetal neuroprotection. It stated that "the available evidence suggests that magnesium sulfate given before anticipated early preterm birth reduces the risk of cerebral palsy in surviving infants." No official opinion was given on a gestational age cut-off, but it was recommended that physicians develop specific guidelines around the issues of inclusion criteria, dosage, concurrent tocolysis, and monitoring in accordance with 1 of the larger trials. Similarly, the World Health Organization also strongly recommends use of magnesium sulphate for fetal neuroprotection in its 2015 recommendations on interventions to improve preterm birth outcomes but cites further researching on dosing regimen and re-treatment.

SPONSORS

Canadian Institutes of Health Research (CIHR).

SUMMARY STATEMENT

RECOMMENDATIONS.

The effect of antenatal magnesium sulfate on intraventricular hemorrhage in premature infants: a systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review and meta-analysis study was to determine the pooled estimate of the effect of antenatal magnesium sulfate (MgSO4) on intraventricular hemorrhage (IVH) in premature infants.

METHODS

Two review authors independently searched all randomized clinical trials from international databases, including Medline (PubMed), Web of Sciences, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and Research Registers of ongoing trials (ClinicalTrials.gov), from January 1989 to August 2017. Two independent review authors were responsible for data collection. After extracting the necessary information from the evaluated articles, metaanalysis of the data was performed using Stata version 14. Also, sources of heterogeneity among studies were determined by Meta regression.

RESULTS

In this study, among 126 articles that were extracted from primary studies, 7 papers that evaluated the effect of MgSO4 on IVH were eligible for inclusion in the meta-analysis. The results of the meta-analysis showed that pooled relative risk (95% confidence interval [CI]) was 0.80 (95% CI, 0.63 to 1.03) for the effect of MgSO4 on IVH.

CONCLUSION

RESULTS

of this study showed that although MgSO4 had a protective effect on IVH in premature infants, this effect was not statistically significant. Further studies are needed to determine the best dosage, timing, and gestational age to achieve the optimum effect of MgSO4 on IVH.

SYSTEMATIC REVIEW REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO) Identifier: CRD42019119610.

The role of magnesium sulfate (MgSO4) in fetal neuroprotection

Prevention of neurologic disability associated with preterm birth is one of the major challenges in current perinatal medicine. Magnesium sulfate (MgSO₄), the focus of this review has been proposed as major step forward for that matter. MgSO₄ is easily accessible, cheap, and has been proposed as a mandatory part of the management of inevitable preterm birth. The results of the various RCT's on the use of MgSO₄ for neuroprotection has been the subject of many systematic reviews, other studies focused on dosing schedules, side effects and only a few focused on exploring magnesium's mechanism of action. Meanwhile, many guidelines worldwide have plugged MgSO₄ as an essential ingredient of daily best practice when managing inevitable preterm birth because it has been shown to reduce the risk of severe neurologic deficit, in particular, cerebral palsy in appropriately selected patients. The more premature, the greater benefit associated with the use of antenatal MgSO₄. The dose of 4 g given intravenously 15 min continued by 1 g/h until maximum 24 h and minimum for 4 h is the standard regiment proposed in most guidelines. It should be noted, however, that a recent study found that a total dose of 64 g was associated with the maximum protective effect. Only the protocol used by the largest RCT, the BEAM trial, with a loading dose of 6 g initially followed by a 2-g/h maintenance dose, if continued for 24 h would give a total dose over 50 g. Other studies report on an increased risk of neonatal death with these high doses. Several studies expressed concerns about the risk of serious side effects for both mother and neonate. The results from the systematic review showed that the most commonly used dosage, 4 g bolus continued by 1 g/h maintenance, did not increase neonatal mortality and other suspected neonatal complication such as neonatal asphyxia, spontaneous intestinal perforation, necrotizing enterocolitis, and feeding intolerance. Giving a single bolus injection of 4 g MgSO4 for stimulating BDNF production in highly "suspicious" preterm labor, and 4 g again when preterm birth become inevitable may be best from a safety perspective and also appears to have a stronger rationale.

Association of histological chorioamnionitis and magnesium sulfate treatment in singleton and dichorionic twin pregnancies with preterm premature rupture of membranes: preliminary observations

Objective To evaluate the possible association between antenatal magnesium sulfate treatment with histological chorioamnionitis in patients with singleton or dichorionic twins that had preterm premature rupture of the membranes. Methods This was an observational study performed in patients admitted to the hospital with rupture of membranes before 34 weeks' gestation. The primary outcome was histological chorioamnionitis and the primary predictor was antenatal magnesium sulfate treatment. A logistic regression model was used without consideration of other antenatal medical treatments. Results Among 107 patients with preterm deliveries, 57 were admitted to the hospital before 34 weeks' gestation with preterm premature rupture of membranes. Fifty-cases were excluded from the analysis because they were admitted after 34 weeks' gestation, delivered before 24 weeks' gestation or had intrauterine fetal demise or monochorionic twins. The logistic regression analysis adjusting for maternal age, gravidity, parity, multiple gestation, gestational age at delivery, and birthweight, indicated that patients with singleton pregnancies and histological chorioamnionitis had received magnesium sulfate antenatally more frequently (χ2=6.46; P=0.01). The association between histological chorioamnionitis and magnesium sulfate treatment was not found among patients with dichorionic twin pregnancies with one intact gestational sac. Conclusions In this cohort of patients with preterm premature rupture of membranes admitted to the hospital before 34 week's gestation, those with singleton pregnancies treated antenatally with magnesium sulfate for neonatal neuroprotection had a greater rate of histological chorioamnionitis.

Fetal Neuroprotection by Magnesium Sulfate: From Translational Research to Clinical Application

Despite improvements in perinatal care, preterm birth still occurs regularly and the associated brain injury and adverse neurological outcomes remain a persistent challenge. Antenatal magnesium sulfate administration is an intervention with demonstrated neuroprotective effects for preterm births before 32 weeks of gestation (WG). Owing to its biological properties, including its action as an N-methyl-d-aspartate receptor blocker and its anti-inflammatory effects, magnesium is a good candidate for neuroprotection. In hypoxia models, including hypoxia-ischemia, inflammation, and excitotoxicity in various species (mice, rats, pigs), magnesium sulfate preconditioning decreased the induced lesions’ sizes and inflammatory cytokine levels, prevented cell death, and improved long-term behavior. In humans, some observational studies have demonstrated reduced risks of cerebral palsy after antenatal magnesium sulfate therapy. Meta-analyses of five randomized controlled trials using magnesium sulfate as a neuroprotectant showed amelioration of cerebral palsy at 2 years. A meta-analysis of individual participant data from these trials showed an equally strong decrease in cerebral palsy and the combined risk of fetal/infant death and cerebral palsy at 2 years. The benefit remained similar regardless of gestational age, cause of prematurity, and total dose received. These data support the use of a minimal dose (e.g., 4 g loading dose ± 1 g/h maintenance dose over 12 h) to avoid potential deleterious effects. Antenatal magnesium sulfate is now recommended by the World Health Organization and many pediatric and obstetrical societies, and it is requisite to maximize its administration among women at risk of preterm delivery before 32 WG.

Use and attitudes of obstetricians toward 3 high-risk interventions in MFMU Network hospitals

OBJECTIVE

We sought to evaluate the frequency of, and factors associated with, the use of 3 evidence-based interventions: antenatal corticosteroids for fetal lung maturity, progesterone for prevention of recurrent preterm birth, and magnesium sulfate for fetal neuroprotection.

STUDY DESIGN

A self-administered survey was conducted from January through May 2011 among obstetricians from 21 hospitals that included 30 questions regarding their knowledge, attitudes, and practice of the 3 evidence-based interventions and the 14-item short version of the Team Climate for Innovation survey. Frequency of use of each intervention was ascertained from an obstetrical cohort of women between January 2010 and February 2011.

RESULTS

A total of 329 obstetricians (74% response rate) who managed 16,946 deliveries within the obstetrical cohort participated in the survey. More than 90% of obstetricians reported that they incorporated each intervention into routine practice. Actual frequency of administration in women eligible for the treatments was 93% for corticosteroids, 39% for progesterone, and 71% for magnesium sulfate. Provider satisfaction with quality of treatment evidence was 97% for corticosteroids, 82% for progesterone, and 57% for magnesium sulfate. Obstetricians perceived that barriers to treatment were most frequent for progesterone (76%), 30% for magnesium sulfate, and 17% for corticosteroids. Progesterone use was more frequent among patients whose provider reported the quality of the evidence was above average to excellent compared with poor to average (42% vs 25%, respectively; P < .001), and they were satisfied with their knowledge of the intervention (41% vs 28%; P = .02), and was less common among patients whose provider reported barriers to hospital or pharmacy drug delivery (31% vs 42%; P = .01). Corticosteroid administration was more common among patients who delivered at hospitals with 24 hours a day-7 days a week maternal-fetal medicine specialist coverage (93% vs 84%; P = .046), CONCLUSION: Obstetricians in Maternal-Fetal Medicine Units Network hospitals frequently use these evidence-based interventions; however, progesterone use was found to be related to their assessment of evidence quality. Neither progesterone nor the other interventions were associated with overall climate of innovation within a hospital as measured by the Team Climate for Innovation. National Institutes of Health Consensus Conference Statements may also have an impact on use; there is such a statement for antenatal corticosteroids but not for progesterone for preterm prevention or magnesium sulfate for fetal neuroprotection.

Neuroprotection in preterm infants

Preterm infants born before the 30th week of pregnancy are especially at risk of perinatal brain damage which is usually a result of cerebral ischemia or an ascending intrauterine infection. Prevention of preterm birth and early intervention given signs of imminent intrauterine infection can reduce the incidence of perinatal cerebral injury. It has been shown that administering magnesium intravenously to women at imminent risk of a preterm birth leads to a significant reduction in the likelihood of the infant developing cerebral palsy and motor skill dysfunction. It has also been demonstrated that delayed clamping of the umbilical cord after birth reduces the rate of brain hemorrhage among preterm infants by up to 50%. In addition, mesenchymal stem cells seem to have significant neuroprotective potential in animal experiments, as they increase the rate of regeneration of the damaged cerebral area. Clinical tests of these types of therapeutic intervention measures appear to be imminent. In the last trimester of pregnancy, the serum concentrations of estradiol and progesterone increase significantly. Preterm infants are removed abruptly from this estradiol and progesterone rich environment. It has been demonstrated in animal experiments that estradiol and progesterone protect the immature brain from hypoxic-ischemic lesions. However, this neuroprotective strategy has unfortunately not yet been subject to sufficient clinical investigation.

Antenatal magnesium sulfate and spontaneous intestinal perforation in infants less than 25 weeks gestation

OBJECTIVE

Evaluate spontaneous intestinal perforation (SIP)/death among extremely low birthweight (ELBW) infants before, during and after initiation of an antenatal magnesium for neuroprotection protocol (MgPro).

STUDY DESIGN

We tested associations between SIP/death and magnesium exposure, gestational age (GA) and interactions with GA and magnesium exposure in a cohort of inborn ELBW infants before, during and after MgPro.

RESULT

One hundred and fifty-five ELBW infants were included, 81 before, 23 during and 51 after MgPro. ELBW infants (78.3%) were exposed to Mg during MgPro compared with 50.6% and 60.8% before and after, respectively. Incidence of SIP on protocol was 30.4% vs 12.9% off protocol (P=0.03). GA was strongly associated with SIP (P<0.01). Antenatal Mg dose was also associated with SIP/death regardless of epoch (odds ratio 9.3 (1.04-104.6)), but increased SIP/death was limited to those <25 weeks gestation.

CONCLUSION

Higher Mg dose was associated with higher SIP and death risk among infants with the lowest birthweights. Validation of this observation in larger populations is warranted.

Magnesium sulphate at 30 to 34 weeks' gestational age: neuroprotection trial (MAGENTA)--study protocol

Background

Magnesium sulphate is currently recommended for neuroprotection of preterm infants for women at risk of preterm birth at less than 30 weeks’ gestation, based on high quality evidence of benefit. However there remains uncertainty as to whether these benefits apply at higher gestational ages.

The aim of this randomised controlled trial is to assess whether giving magnesium sulphate compared with placebo to women immediately prior to preterm birth between 30 and 34 weeks’ gestation reduces the risk of death or cerebral palsy in their children at two years’ corrected age.

Methods/design

Design: Randomised, multicentre, placebo controlled trial.

Inclusion criteria: Women, giving informed consent, at risk of preterm birth between 30 to 34 weeks’ gestation, where birth is planned or definitely expected within 24 hours, with a singleton or twin pregnancy and no contraindications to the use of magnesium sulphate.

Trial entry & randomisation: Eligible women will be randomly allocated to receive either magnesium sulphate or placebo.

Treatment groups: Women in the magnesium sulphate group will be administered 50 ml of a 100 ml infusion bag containing 8 g magnesium sulphate heptahydrate [16 mmol magnesium ions]. Women in the placebo group will be administered 50 ml of a 100 ml infusion bag containing isotonic sodium chloride solution (0.9%). Both treatments will be administered through a dedicated IV infusion line over 30 minutes.

Primary study outcome: Death or cerebral palsy measured in children at two years’ corrected age.

Sample size: 1676 children are required to detect a decrease in the combined outcome of death or cerebral palsy, from 9.6% with placebo to 5.4% with magnesium sulphate (two-sided alpha 0.05, 80% power, 5% loss to follow up, design effect 1.2).

Discussion

Given the magnitude of the protective effect in the systematic review, the ongoing uncertainty about benefits at later gestational ages, the serious health and cost consequences of cerebral palsy for the child, family and society, a trial of magnesium sulphate for women at risk of preterm birth between 30 to 34 weeks’ gestation is both important and relevant for clinical practice globally.

Trial registration

Australian New Zealand Clinical Trials Registry - ACTRN12611000491965

Magnesium sulfate during anticipated preterm birth for infant neuroprotection

Advances in medical care of preterm infants, including the widespread use of surfactant and antenatal steroids, and improvements in ventilation management, have increased the survival rates of some of the most vulnerable infants. Yet, the risk of neurologic impairment and long-term medical complications remains a concern. Recently, the use of magnesium sulfate during anticipated preterm birth has been identified as a potential treatment to reduce adverse neurologic outcomes among preterm infants. This article discusses the use of magnesium sulfate for anticipated preterm birth to reduce neurologic impairment in preterm infants, including current clinical practice guidelines and implications for nurses.

Treatment with magnesium sulphate in pre-term birth: a systematic review and meta-analysis of observational studies

Premature birth increases a child's risk of cerebral palsy and death. The aim of this work is to investigate the association between treatment with magnesium sulphate during premature deliveries and infants' cerebral palsy and mortality through a meta-analysis of observational studies. A comprehensive search of the Cochrane Library, EMBASE and the PubMed database from their inceptions to 1 October, 2010 using the keywords 'magnesium sulphate, children/infant/pre-term/premature and cerebral palsy/mortality/morbidity/adverse effects/outcome' identified 11 reports of observational studies. Two authors working independently extracted the data. A meta-analysis of the data found an association between magnesium sulphate treatment and a significantly reduced risk of mortality (RR 0.73; 95% CI 0.61-0.89) and cerebral palsy (OR 0.64; 95% CI 0.47-0.89). Antenatal treatment with magnesium sulphate during premature deliveries seems to be associated with health benefits for the infants. The effective dose and timing, however, is not defined and given the lack of mechanistic understanding of the effect of MgSO(4), a reasonable alternative is a large-scale pragmatic clinical trial.

Antenatal magnesium sulfate and neuroprotection

PURPOSE OF REVIEW

Antenatal magnesium sulfate may reduce the excessive rates of cerebral palsy in survivors of very preterm birth.

RECENT FINDINGS

There are five randomized controlled trials of magnesium sulfate therapy given to the mother prior to very preterm birth which have reported neurological outcomes for the child, in four of which the primary aim of the trial was neuroprotection for the fetus. From meta-analysis of these randomized trials, the rate of cerebral palsy was reduced by magnesium sulfate [relative risk (RR) = 0.69; 95% confidence interval (CI) = 0.54-0.87; five trials; 6145 infants). Magnesium sulfate also lowered the rate of substantial motor dysfunction in early childhood (RR = 0.61; 95% CI = 0.44-0.85; four trials; 5980 infants). In addition, where the main aim of the trial was neuroprotection of the fetus, the rates of the combined outcomes of death or cerebral palsy (RR = 0.86; 95% CI = 0.74-0.98; four trials; 4446 infants) and death or substantial motor dysfunction (RR = 0.85; 95% CI = 0.73-0.98; three trials; 4387 infants) were significantly lower with magnesium.

SUMMARY

On the basis of these findings several countries have now released clinical practice guidelines recommending antenatal magnesium sulfate prior to very preterm birth.

Antenatal magnesium individual participant data international collaboration: assessing the benefits for babies using the best level of evidence (AMICABLE)

BACKGROUND

The primary aim of this study is to assess, using individual participant data (IPD) meta-analysis, the effects of administration of antenatal magnesium sulphate given to women at risk of preterm birth on important clinical outcomes for their child such as death and neurosensory disability. The secondary aim is to determine whether treatment effects differ depending on important pre-specified participant and treatment characteristics, such as reasons at risk of preterm birth, gestational age, or type, dose and mode of administration of magnesium sulphate.

METHODS

DESIGN

The Antenatal Magnesium Individual Participant Data (IPD) International Collaboration: assessing the benefits for babies using the best level of evidence (AMICABLE) Group will perform an IPD meta-analysis to answer these important clinical questions. SETTING/TIMELINE: The AMICABLE Group was formed in 2009 with data collection commencing late 2010.

INCLUSION CRITERIA

Five trials involving a total 6,145 babies are eligible for inclusion in the IPD meta-analysis. PRIMARY STUDY OUTCOMES: For the infants/children: Death or cerebral palsy. For the women: Any severe maternal outcome potentially related to treatment (death, respiratory arrest or cardiac arrest).

DISCUSSION

Results are expected to be publicly available in 2012.

The role of magnesium sulfate in the prevention of cerebral palsy

Magnesium sulfate (MgSO4) has been widely used in the perinatal arena for many decades. It has been used for tocolysis in the U.S. for more than 60 years. Estimations of MgSO4 use for preterm labor (less than 34 weeks of gestation) run as high as 80 percent. Magnesium sulfate is a smooth, skeletal, and cardiac muscle depressant. It is used for preterm labor because of its potential to decrease muscle contractility by interfering with calcium uptake in the cells. Thousands of moms and babies have been exposed to this medication even though tocolysis remains an off-label use, the exact mechanism of action is not completely understood, and there are studies that show that it is ineffective for this indication, and no evidence that it improves perinatal outcomes.1-3 Additionally, it is a high alert medication because of its narrow therapeutic window and the risk of causing an immediate life-threatening condition (acute respiratory failure) if an error in administration occurs.4.

Different magnesium sulphate regimens for neuroprotection of the fetus for women at risk of preterm birth

BACKGROUND

The effectiveness of antenatal magnesium sulphate for neuroprotection of the fetus, infant, and child prior to very preterm birth, when given to women considered at risk of preterm birth, has been established. There is currently no consensus as to the regimen to use in terms of the dose, duration, the use of repeat dosing and timing.

OBJECTIVES

To assess the comparative effectiveness and adverse effects of different magnesium sulphate regimens for neuroprotection of the fetus in women considered at risk of preterm birth.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 December 2011).

SELECTION CRITERIA

Randomised trials comparing different magnesium sulphate regimens when used for neuroprotection of the fetus in women considered at risk of preterm birth. We planned to include cluster trials. We planned to exclude quasi-randomised trials and those with a crossover design. We planned to include trials published as full-text papers, along with those published in abstract form only.

DATA COLLECTION AND ANALYSIS

We planned that at least two review authors would assess trial eligibility.

MAIN RESULTS

No eligible completed trials were identified.

AUTHORS' CONCLUSIONS

Although strong evidence supports the use of antenatal magnesium sulphate for neuroprotection of the fetus prior to very preterm birth, no trials comparing different treatment regimens have been completed. Research should be directed towards comparisons of different dosages and other variations in regimens, evaluating both maternal and infant outcomes.

Magnesium sulfate tocolysis and intraventricular hemorrhage in very preterm infants

OBJECTIVE

To estimate the contributory effect of tocolytic magnesium sulfate (MgSO4) exposure to intraventricular hemorrhage (IVH) in preterm infants born at 23-31 wks gestation to mothers without evidence of pregnancy induced hypertension and/or preeclampsia.

METHODS

Cases with IVH and controls without IVH were selected from a population-based cohort of preterm infants admitted from January 2004 through May 2008 to the Level III Neonatal Intensive Care Unit (NICU) at Robert Wood Johnson University Hospital. Cases and controls were matched primarily by exact gestational age in completed weeks and secondarily by the birth weight that was same or similar (+/-100 g). The odds of tocolytic MgSO(4) exposure among the cases and controls was tested in a regression model to control the difference in demographic and clinical factors between the IVH cases (IVH+) and controls without IVH (IVH-).

RESULTS

Eighty-nine IVH cases and 89 controls were comparable for parity, mode of delivery, antenatal corticosteroid exposure, and surfactant administration. IVH cases were less likely to have preterm premature rupture of membranes and were more likely to be born with low Apgar scores and require ventilation. Among the IVH cases, 30.3% of infants were exposed to tocolytic MgSO4 as compared to 47.2% of controls (Odds Ratio adjusted 0.471, 95% Confidence Interval 0.241, 0.906).

CONCLUSIONS

Among the preterm born infants with gestational age 23-31 wks and IVH, tocolytic MgSO4 exposure was less likely to be observed than in neonates with similar clinical characteristics but without IVH, thereby suggesting that antenatal exposure to MgSO(4) may have a protective effect against IVH.

The use of antenatal magnesium sulfate for neuroprotection for infants born prematurely

Cerebral palsy occurs in three to four infants per 1000 live births. Preterm birth prior to 34 weeks’ gestation is a major risk factor. Five randomized controlled trials of antenatal magnesium sulfate (MgSO₄) found a trend of reduced risk of cerebral palsy and mortality in preterm infants. Three meta-analyses using the data from the five randomized controlled trials, which included a total of 5235 prospectively evaluated fetuses, found that MgSO₄ given to women at risk of premature birth significantly reduced the risk of cerebral palsy by 30% without increasing the risk of perinatal or infant death. The implication for clinical practice is that MgSO₄ should be considered for use in patients at high risk of delivery before 34 weeks’ gestation.

Antenatal magnesium sulfate for the prevention of cerebral palsy in preterm infants less than 34 weeks' gestation: a systematic review and metaanalysis

We conducted a systematic review and metaanalysis of randomized controlled trials to determine whether magnesium sulfate administered to women at risk of preterm delivery before 34 weeks of gestation may reduce the risk of cerebral palsy in their children. Six trials involving 4796 women and 5357 infants were included. Antenatal magnesium sulfate was associated with a significant reduction in the risk of cerebral palsy (relative risk [RR], 0.69; 95% confidence interval [CI], 0.55-0.88), moderate or severe cerebral palsy (RR, 0.64; 95% CI, 0.44-0.92), and substantial gross motor dysfunction (RR, 0.60; 95% CI, 0.43-0.83). There was no overall difference in the risk of total pediatric mortality (RR, 1.01; 95% CI, 0.89-1.14). Minor side effects were more frequent among women receiving magnesium sulfate. In conclusion, magnesium sulfate administered to women at risk of delivery before 34 weeks of gestation reduces the risk of cerebral palsy.

Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus

BACKGROUND

Epidemiological and basic science evidence suggests that magnesium sulphate before birth may be neuroprotective for the fetus.

OBJECTIVES

To assess the effects of magnesium sulphate as a neuroprotective agent when given to women considered at risk of preterm birth.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2008).

SELECTION CRITERIA

Randomised controlled trials of antenatal magnesium sulphate therapy in women threatening or likely to give birth at less than 37 weeks' gestational age. For one subgroup analysis, studies were broadly categorised by the primary intent of the study into "neuroprotective intent", or "other intent (maternal neuroprotective - pre-eclampsia)", or "other intent (tocolytic)".

DATA COLLECTION AND ANALYSIS

At least two authors assessed trial eligibility and quality, and extracted data.

MAIN RESULTS

Five trials (6145 babies) were eligible for this review. Antenatal magnesium sulphate therapy given to women at risk of preterm birth substantially reduced the risk of cerebral palsy in their child (Relative Risk (RR) 0.68; 95% Confidence interval (CI) 0.54 to 0.87; five trials; 6145 infants). There was also a significant reduction in the rate of substantial gross motor dysfunction (RR 0.61; 95% CI 0.44 to 0.85; four trials; 5980 infants). No statistically significant effect of antenatal magnesium sulphate therapy was detected on paediatric mortality (RR 1.04; 95% CI 0.92 to 1.17; five trials; 6145 infants), or on other neurological impairments or disabilities in the first few years of life. Overall there were no significant effects of antenatal magnesium therapy on combined rates of mortality with cerebral palsy, although there were significant reductions for the neuroprotective groups RR 0.85; 95% CI 0.74 to 0.98; four trials; 4446 infants, but not for the other intent subgroups. There were higher rates of minor maternal side effects in the magnesium groups, but no significant effects on major maternal complications.

AUTHORS' CONCLUSIONS

The neuroprotective role for antenatal magnesium sulphate therapy given to women at risk of preterm birth for the preterm fetus is now established. The number of women needed to be treated to benefit one baby by avoiding cerebral palsy is 63 (95% confidence interval 43 to 87). Given the beneficial effects of magnesium sulphate on substantial gross motor function in early childhood, outcomes later in childhood should be evaluated to determine the presence or absence of later potentially important neurological effects, particularly on motor or cognitive function.

Infection and fetal neurologic injury

PURPOSE OF REVIEW

Antepartum fetal exposure to infection/inflammation is a more important risk factor for brain injury than intrapartum hypoxia in both the term and preterm neonate. Such preexisting infection/inflammation might also provide the platform for subsequent intrapartum hypoxic-ischaemic damage. This review will discuss the complex interaction between fetal inflammatory response and neurotoxicity, and focus on the clinical implications of the synergistic interaction between infection/inflammation and hypoxia-ischaemia.

RECENT FINDINGS

Current evidence indicates that inflammatory mediators are directly neurotoxic, and also sensitize the fetal brain tissue to a greater magnitude of damage by subsequent hypoxia-ischaemia by lowering the threshold at which hypoxia initiates neuronal cell apoptosis/cell death.

SUMMARY

Further studies are urgently needed to characterize the fetuses at risk of damage, the duration of exposure required to cause injury, the influence of gestational age and whether Caesarean section may be protective. Until then clinicians should maintain a high level of surveillance in labours complicated by infection and avoid additional exposure to hypoxic-ischaemic insults.

Antenatal magnesium sulphate neuroprotection in the preterm infant

Very preterm infants have high rates of neurological impairments and disabilities. These rates have not diminished as the survival rates have improved. Basic science research suggests that magnesium sulphate before birth can be neuroprotective for the preterm fetus. Some, but not all, observational studies in humans also suggest a protective effect of antenatal magnesium sulphate on cerebral palsy. Four randomised controlled trials of antenatal magnesium sulphate have reported long-term neurological effects in surviving infants, but only one of these was designed specifically to evaluate the long-term effects of treatment. These studies found that, overall, antenatal magnesium sulphate therapy had no significant effect on paediatric mortality or neurological outcomes in the first few years of life, including cerebral palsy, but it was found to lower the rate of motor problems at 2 years of age in one study. The role for antenatal magnesium sulphate therapy as a neuroprotective agent for the preterm fetus is not yet established.

Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus

BACKGROUND

Epidemiological and basic science evidence suggests that magnesium sulphate before birth may be neuroprotective for the fetus.

OBJECTIVES

To assess the effectiveness and safety of magnesium sulphate as a neuroprotective agent when given to women considered at risk of preterm birth.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (October 2006), CENTRAL (The Cochrane Library 2006, Issue 3), MEDLINE (1966 to October 2006), EMBASE (1980 to October 2006), Current Contents (1992 to October 2006), references of retrieved articles, and abstracts submitted to the Society for Pediatric Research (1996 to 2006).

SELECTION CRITERIA

Randomised controlled trials of antenatal magnesium sulphate therapy given to women threatening or likely to give birth at less than 37 weeks' gestational age.

DATA COLLECTION AND ANALYSIS

We independently extracted data regarding clinical outcomes including paediatric mortality, neurologic outcome of survivors (including blindness, deafness, cerebral palsy and major neurosensory disability), and maternal complications and side-effects. At least two authors assessed trial eligibility and quality, and extracted data.

MAIN RESULTS

Four trials (3701 babies) were eligible for this review. No statistically significant effect of antenatal magnesium sulphate therapy was detected on any major paediatric outcome, including mortality (e.g., paediatric mortality relative risk (RR) 0.97; 95% confidence interval (CI) 0.74 to 1.28; four trials; 3701 infants), and neurological outcomes in the first few years of life, including cerebral palsy (RR 0.77; 95% CI 0.56 to 1.06; four trials; 3701 infants), neurological impairments or disabilities. There were also no significant effects of antenatal magnesium therapy on combined rates of mortality with neurologic outcomes. There was a significant reduction in the rate of substantial gross motor dysfunction (RR 0.56; 95% CI 0.33 to 0.97; two trials; 2848 infants). There were higher rates of minor maternal side-effects in the magnesium groups, but no significant effects on major maternal complications.

AUTHORS' CONCLUSIONS

The role for antenatal magnesium sulphate therapy as a neuroprotective agent for the preterm fetus is not yet established. Given the possible beneficial effects of magnesium sulphate on gross motor function in early childhood, outcomes later in childhood should be evaluated to determine the presence or absence of later potentially important neurologic effects, particularly on motor or cognitive function. Further information will be available from one of the studies where outcomes are being evaluated again at eight to nine years of age, and from another trial currently in progress.

Magnesium sulfate exposure increases fetal blood flow redistribution to the brain during acute non-acidemic hypoxemia in goats

BACKGROUND

It is still controversial that intrapartum exposure to magnesium may or may not reduce brain damage in premature infants in human and animal models.

AIMS

We investigated the effect of hypoxemia alone under magnesium exposure on fetal cardiovascular changes in chronically catheterized goat fetuses.

STUDY DESIGN

We performed a 3-day experimental protocol with control (10% glucose) on day 1, recovery on day 2, and magnesium on day 3. Magnesium sulfate was directly infused to fetuses in a bolus dose of 270 mg/kg followed by 80 mg/kg/h. Hypoxemia was induced by maternal inhalation of nitrogen gas on day 1 and on day 3. Cerebral blood flow was measured by colored microsphere techniques. Repeated measure ANOVA and Bonferroni's/Dunn's test were used for comparison.

SUBJECTS

Six Japanese Saanen goats at 0.85 gestation.

OUTCOME MEASURES

Fetal heart rate, blood pressure, and cerebral blood flow.

RESULTS

Ionized magnesium concentrations were significantly increased. Fetal PO2 decreased significantly from 30 mmHg to 14 mmHg without acidemia. Magnesium exposure significantly attenuated hypoxemia-induced bradycardia but did not affect blood pressure. Hypoxemia significantly increased fetal brain blood flow from the pre-hypoxic levels on day 1. Magnesium exposure further increased hypoxemia-induced brain blood flow on day 3, but statistical significance was limited to the cerebral cortex.

CONCLUSION

In near-term, initially healthy goat fetuses, brain blood flow during acute hypoxemia was significantly increased with magnesium sulfate exposure.

Epidemiology of cerebral palsy

The term cerebral palsy refers to a range of clinical symptoms, with related service requirements, resulting from lesions or abnormalities in the brain arising early in life. It is not a diagnosis; aetiology and pathology are variable. This article discusses the definition and differential classification of cerebral palsy, describes trends in its frequency over time stratified by associated variables, and briefly reviews the most recent findings concerning its aetiology.

Neonatal color Doppler US study: normal values of cerebral blood flow velocities in preterm infants in the first month of life

The aim of this study is to generate normal reference values of cerebral blood flow velocities (CBFV) and Doppler indices (DI) in the anterior (ACA) and the middle (MCA) cerebral arteries during the first month of life in "healthy" preterm infants. CBFV were obtained with color Doppler technique in seventy selected preterm infants divided in four groups of gestational age (GA) (25 to 28; 29 to 30; 31 to 32; 33 to 35 wk). Our data demonstrate that CBFV increase with rising GA, birth weight (BW) and postnatal age. Additionally, we can provide the median values, tenth and ninetieth percentiles of CBFV and DI, in the ACA and MCA in each GA group as reference normal values of CBFV and DI in preterm newborn.

Brain lesions in newborns exposed to high-dose magnesium sulfate during preterm labor

High-dosage, tocolytic magnesium sulfate (MgSO4) administered to pregnant women during preterm labor can be toxic, and sometimes lethal, for their newborns (Cochrane Database of Systematic Reviews (relative mortality risk 2.82, 95% confidence interval 1.2-6.6)). Based on the results of the Magnesium and Neurologic Endpoints Trial and the work of many others, a unifying triangular concept is proposed to account for the increased prevalence of brain lesions, with their likely resultant mortality, in neonates and infants exposed to high-dose MgSO4 in the context of preterm labor. We review the evidence that: (1) elevated circulating levels of serum ionized magnesium occurring in mothers, and therefore in their babies, at the time of delivery are associated with subsequent neonatal intraventricular hemorrhage (IVH); (2) neonatal IVH is strongly associated with lenticulostriate vasculopathy (LSV), an unusual mineralizing lesion involving the thalami and basal ganglia of the neonate; and, (3) exposure to 50 g or more of tocolytic MgSO4 during preterm labor is associated with the development of LSV.

Genetic polymorphisms and cerebral palsy in very preterm infants

In the present study, we examine whether selected genetic polymorphisms contribute to the development of cerebral palsy (CP) in very preterm infants. Subjects were 96 singleton infants with later-diagnosed CP and 119 control children, white non-Hispanic (n for CP=74, controls=88) or white Hispanic (CP=22, controls=31), born <32 wk gestation. Presence of CP was identified through state service agencies, with review of medical records. DNA extracted from archived neonatal blood was genotyped using multi-locus polymerase chain reaction amplification and immobilized sequence-specific oligonucleotide probes. Single nucleotide polymorphisms (SNPs) showing evidence of association with development of CP were endothelial nitric oxide synthase (eNOS) A(-922)G, factor 7 (F7) arg353gln and del(-323)10bp-ins, and lymphotoxin A (LTA) thr26asn. In white non-Hispanic children, beta-2 adrenergic receptor gln27glu was associated with CP risk; in Hispanic children, plasminogen activator inhibitor-1 (PAI-1) 4G(-675)5G and G11053T were associated with risk of CP. In a logistic regression considering these SNPs simultaneously in non-Hispanics, an association with CP was observed for heterozygotes of eNOS -922 (OR 3.0, CI 1.4-6.4), F7 (OR 2.7, CI 1.1-6.5), LTA (OR 2.1, CI 1.0-4.6), and PAI-1 (OR 3.2, CI 1.2-8.7). Factor 5, Factor 2, methylene tetrahydrofolate reductase, tumor necrosis factor-alpha, and other SNPs tested were not significantly associated with CP risk. We conclude that further study of genetic factors that may influence susceptibility to CP in very preterm infants is warranted.

Hospitalization and infant outcomes among women exposed and unexposed to tocolysis

OBJECTIVE

To examine whether infants exposed to tocolytics are at increased risk for selected adverse clinical and hospitalization outcomes.

STUDY DESIGN

We conducted a population-based cohort study of women with preterm labor, in Washington State from 1989 to 2001 (N=79,679), using linked hospitalization records. Relative risks for infant outcomes were estimated using multivariate logistic regression.

RESULTS

Adjusted risk estimates for infants exposed to tocolysis were greater for respiratory distress (RR=1.5, 95% CI 1.4 to 1.6), intubation (RR=1.4, 95% CI 1.2 to 1.5), and bacterial infection (RR=1.6, 95% CI 1.4 to 1.8). Exposed infants were also more likely to have birth hospitalizations >2 days (RR=1.4, 95% CI 1.3 to 1.4), require transfer (RR=1.5, 95% CI 1.3 to 1.8), have increased hospital costs (RR=2.3, 95% CI 2.2 to 2.4), and require readmisssion within the first year of life (RR=1.2, 95% CI 1.1 to 1.3).

CONCLUSION

Infants exposed to tocolytics appeared to have relatively poorer hospitalization and clinical outcomes; significant benefits were not observed.

The combined maternal administration of magnesium sulfate and aminophylline reduces intraventricular hemorrhage in very preterm neonates

OBJECTIVE

To determine whether the adjunctive administration of aminophylline and magnesium sulfate to mothers at risk for preterm birth can reduce the rate of intraventricular hemorrhage in neonates born at less than 30 weeks of gestation.

STUDY DESIGN

A prospective study was conducted to determine whether the rate of intraventricular hemorrhage was different in patients at risk for preterm delivery treated with ritodrine, magnesium sulfate, aminophylline, and corticosteroids (group A) versus patients treated with ritodrine and corticosteroids (group B). During the study period (January 1996 to December 2001), 125 patients enrolled in the study. Treatment was assigned by alternative allocation, and the study was designed to compare the rate of intraventricular hemorrhage in neonates born before the 30th week of gestation (primary outcome), 78 newborns in group A and 68 in group B. The proportion of neonates with intraventricular hemorrhage was calculated, and data were analyzed with Student t test, chi 2 , and logistic regression analysis.

RESULTS

The frequency of severe respiratory distress syndrome needing surfactant replacement and high-pressure positive ventilation, patent ductus arteriosus, and retinopathy of prematurity was not different between the 2 groups. However, the rate of intraventricular hemorrhage was lower in neonates born before 30 weeks whose mothers received adjunctive aminophylline and magnesium sulphate (group A) than in the group that did not receive these 2 agents (group B). The overall frequency of intraventricular hemorrhage was 5.1% (4/78) versus 20.6% (14/68) ( P < .001), and the frequency of intraventricular hemorrhage grade 3-4 was 1.3% (1/78) versus 10.3 % (7/68; P < .001), respectively.

CONCLUSION

Adjunctive maternal administration of aminophylline and magnesium sulfate was associated with a significant reduction in the rate of intraventricular hemorrhage in neonates born before 30 completed weeks.

New Data on the Importance of Gestational Mg Deficiency

Chronic primary Mg deficiency is frequent. About 20% of the population consumes less than two-thirds of the RDA for Mg. Women, particularly, have low intakes. For example, in France, 23% of women and 18% of men have inadequate intakes. Mg deficiency during pregnancy can induce maternal, fetal, and pediatric consequences that might last throughout life. Studies of gestational Mg deficiency in animals show that Mg deficiency may have marked effects on parturition and postuterine involution. It has interfered with fetal growth and development, and caused morbidity from hematological effects and disturbances in temperature regulation, to teratogenic effects. Emphasis, here, is on effects of chronic clinical gestational Mg deficiency as it affects the infant. Premature labor, contributed to by uterine hyperexcitability caused by chronic maternal Mg deficiency, that can be intensified by stress, gives rise to preterm birth. If the only cause of uterine overactivity is Mg deficiency, its supplementation constitutes nontoxic tocolytic treatment, as an adjuvant treatment, that is devoid of toxicity and enhances efficacy and safety of tocolytic drugs such as beta-2 mimetics. Evidence is considered that Mg deficiency or Mg depletion can contribute to the Sudden Infant Death Syndrome (SIDS). SIDS may be a fetal consequence of maternal Mg deficiency through impaired control of Brown Adipose Tissue (BAT) thermoregulation mechanisms leading to a modified temperature set point. SIDS can result from dysthermias: hypo- or hyperthermic forms. Possibly, simple nutritional Mg supplements might be preventive. Various stresses in an infant can transform simple Mg deficiency into Mg depletion. For example, lying prone can be stressful for the baby, as can parental smoking. The role of chronopathological stress appears to be often neglected, as it constitutes a clinical form of primary hypofunction of the biological clock [with its anatomical and clinical stigma such as reduced production of melatonin (MT) and of its urinary metabolite: 6 Sulfatoxy-Melatonin (6 SMT)]. SIDS might be linked to impaired maturation of both the photoneuroendocrine system and BAT. Prophylaxis of this form of SIDS should include atoxic nutritional Mg therapy for pregnant women with total light deprivation at night for the infant. Consequences of maternal primary Mg deficiency have been inadequately studied. To determine ultimate outcomes of gestational Mg deficiency in infants, a long-term multicenter placebo-controlled prospective study should undertaken on effects of maternal nutritional Mg supplementation on lethality/morbidity in fetus, neonates, infants, children and adults, not only during pregnancy and the baby's first year, but throughout life.

Second overview of relationships between antenatal pharmacologic magnesium sulfate and neurologic outcomes in children

In the last ten years, the body of scientific knowledge concerning the use of antenatal pharmacologic magnesium sulfate (MgSO4) has become substantially larger. Several randomized controlled trials have provided compelling evidence that MgSO4 is the drug of choice for maternal seizure prophylaxis in toxemia. In contrast, the recent Cochrane Systematic Review, as well as other studies, have shown there is no evidence basis for the use of MgSO4 for tocolysis. Furthermore, when tocolytic-strength doses of MgSO4 are employed, there is an excess risk for total pediatric mortality (Cochrane Systematic Review and our own previous work). It is conceivable, nonetheless, that low doses of MgSO4, when used as prophylaxis in some selected cases of preterm labor, may ultimately be shown to be neuroprotective for a relatively small number of children. Unfortunately, the indiscriminate use of high-dosage MgSO4 for attempted tocolysis in preterm labor is much more likely to cause harm than do good.

Fetoplacental vascular tone is modified by magnesium sulfate in the preeclamptic ex vivo human placental cotyledon

OBJECTIVE

The purpose of this study was to evaluate fetoplacental vascular tone and response to a vasoconstrictor in placentas of preeclamptic and normotensive pregnancies with and without the presence of magnesium sulfate.

STUDY DESIGN

Two cotyledons from each placenta were selected from preeclamptic (n=8) and normotensive (n=7) pregnancies. In one cotyledon from each pair, the maternal circuit was perfused with magnesium sulfate. The fetal arteries were injected sequentially with angiotensin II (10(-10)mol and 10(-11.5) mol). Perfusion pressures and response to angiotensin II were compared, with regard to preeclampsia and exposure to magnesium sulfate.

RESULTS

Perfusion pressure was higher in preeclamptic placentas, compared with normotensive placentas (30.4 mm Hg vs 24.4 mm Hg, P=.02). There was a decrease in perfusion pressure with exposure to magnesium sulfate in preeclamptic placentas (22.5 mm Hg, P<.01), but not in normotensive placentas. Fetoplacental vascular response to angiotensin II was not affected by preeclampsia or magnesium sulfate.

CONCLUSION

In placentas from preeclamptic pregnancies there is increased fetoplacental perfusion pressure, which decreases with exposure to sulfate.

The therapeutic use of magnesium in anesthesiology, intensive care and emergency medicine: a review

PURPOSE

To review current knowledge concerning the use of magnesium in anesthesiology, intensive care and emergency medicine.

METHODS

References were obtained from Medline(R) (1995 to 2002). All categories of articles (clinical trials, reviews, or meta-analyses) on this topic were selected. The key words used were magnesium, anesthesia, analgesia, emergency medicine, intensive care, surgery, physiology, pharmacology, eclampsia, pheochromocytoma, asthma, and acute myocardial infarction.

PRINCIPLE FINDINGS

Hypomagnesemia is frequent postoperatively and in the intensive care and needs to be detected and corrected to prevent increased morbidity and mortality. Magnesium reduces catecholamine release and thus allows better control of adrenergic response during intubation or pheochromocytoma surgery. It also decreases the frequency of postoperative rhythm disorders in cardiac surgery as well as convulsive seizures in preeclampsia and their recurrence in eclampsia. The use of adjuvant magnesium during perioperative analgesia may be beneficial for its antagonist effects on N-methyl-D-aspartate receptors. The precise role of magnesium in the treatment of asthmatic attacks and myocardial infarction in emergency conditions needs to be determined.

CONCLUSIONS

Magnesium has many known indications in anesthesiology and intensive care, and others have been suggested by recent publications. Because of its interactions with drugs used in anesthesia, anesthesiologists and intensive care specialists need to have a clear understanding of the role of this important cation.

Therapies administered to mothers at risk for preterm birth and neurodevelopmental outcome in their infants

A decrease in the rate of preterm births and the prevention of prematurity-associated neurodevelopmental morbidity are critical for the reduction of neurodevelopmental disability. Efforts to reduce the overall preterm delivery rate have been unsuccessful. Although progress has been achieved in the prevention of short-term neonatal morbidity over the past several decades, the majority of the improvements have resulted from improved neonatal care. Whether obstetric interventions can improve neurodevelopmental outcome is unknown. The ability to adequately assess obstetric interventions is hampered by the limited number of interventional studies that included long-term outcome assessment. Thus, it is incumbent upon ongoing and future interventional studies to consider long-term outcome assessment as a critical component of the overall evaluation of efficacy of obstetric therapies.

Association between maternal serum ionized magnesium levels at delivery and neonatal intraventricular hemorrhage

OBJECTIVES

To determine whether magnesium sulfate (MgSO(4)) exposure is associated with a reduced risk for neonatal intraventricular hemorrhage (IVH).

STUDY DESIGN

In a randomized, controlled trial, women in preterm labor were randomly assigned to receive MgSO(4), "other" tocolytic, or saline control. At delivery, we collected maternal antecubital and umbilical cord blood for determination of serum ionized magnesium levels. Neonatal IVH was diagnosed by cranial ultrasonogram.

RESULTS

Among 144 infants, 24 were diagnosed with IVH. Using crude intention-to-treat analysis, we found that 18% (13/74) of survivors exposed after birth to MgSO(4) had IVH compared with 16% (11/70) of babies who were not exposed. Infants who had IVH were more likely to have been delivered by mothers with higher serum ionized magnesium (Mg) levels (0.75 vs 0.56 mmol/L) (P =.01). Using multivariable logistic regression, we confirmed that higher Mg levels are a significant predictor of neonatal IVH (adjusted odds ratio, 15.8; 95% CI, 1.4-175.0) even when adjusted for birth weight, gestational age, antenatal hemorrhage, and neonatal glucocorticoid exposure.

CONCLUSIONS

In mothers with preterm labor, our data indicate that antenatal MgSO(4) exposure may be associated with an increased risk for IVH among their newborns.

Preterm labour

Studies in the past year have clarified the roles of inflammatory mediators in preterm labour. Exploration of possible genetic predisposition is just beginning. Ultrasound measurement of cervical length has the potential to predict women at risk of preterm delivery several weeks before it occurs. Biochemical testing such as fetal fibronectin can possibly increase its predictive value and differentiate true preterm labour from more innocent preterm contractions. The use of antibiotics for preterm premature rupture of membranes has been clarified with the ORACLE I trial, which shows health benefits for the neonate with the use of erythromycin, whereas antibiotics do not seem to play a beneficial role in spontaneous preterm labour without evidence of clinical infection. There have been further studies suggesting that agents other than beta-agonists are preferable for acute tocolysis and that repeated doses of corticosteroids should be used with caution.