Magnesium sulfate and risk of postpartum uterine atony and hemorrhage: A meta-analysis

Maternal and neonatal outcomes following magnesium sulfate in the setting of chorioamnionitis: a meta-analysis

PURPOSE

Magnesium sulfate (MgSO4) has been widely used in obstetrics as a mean to help decrease maternal and neonatal morbidity in various antenatal pathology. As a factor, it seems to regulate immunity and can, thus, predispose to infectious morbidity. To date, it remains unknown if its administration can increase the risk of chorioamnionitis. In the present meta-analysis, we sought to accumulate the available evidence.

METHODS

We systematically searched Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL, and Google Scholar databases in our primary search along with the reference lists of electronically retrieved full-text papers.

RESULTS

Eight studies were included that investigated the incidence of chorioamnionitis among parturient that received MgSO4 and control patients. Magnesium sulfate was administered in 3229 women and 3330 women served as controls as they did not receive MgSO4. The meta-analysis of data revealed that there was no association between the administration of magnesium sulfate and the incidence of chorioamnionitis (OR 0.98, 95% CI 0.73, 1.32). Rucker's analysis revealed that small studies did not significantly influence the statistical significance of this finding (OR 1.12, 95% CI 0.82, 1.53). Trial sequential analysis revealed that the required number to safely interpret the primary outcome was not reached. Two studies evaluated the impact of MgSO4 in neonates delivered in the setting of chorioamnionitis. Neither of these indicated the presence of a beneficial effect in neonatal morbidity, including the risk of cerebral palsy, intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia, sepsis, stillbirth, or neonatal death.

CONCLUSION

Current evidence indicates that magnesium sulfate is not associated with an increased risk of maternal chorioamnionitis. However, it should be noted that its effect on neonatal outcomes of offspring born in the setting of chorioamnionitis might be subtle if any, although the available evidence is very limited.

Prenatal Intravenous Magnesium at 30-34 Weeks' Gestation and Neurodevelopmental Outcomes in Offspring: The MAGENTA Randomized Clinical Trial

Importance

Intravenous magnesium sulfate administered to pregnant individuals before birth at less than 30 weeks' gestation reduces the risk of death and cerebral palsy in their children. The effects at later gestational ages are unclear.

Objective

To determine whether administration of magnesium sulfate at 30 to 34 weeks' gestation reduces death or cerebral palsy at 2 years.

Design, Setting, and Participants

This randomized clinical trial enrolled pregnant individuals expected to deliver at 30 to 34 weeks' gestation and was conducted at 24 Australian and New Zealand hospitals between January 2012 and April 2018.

Intervention

Intravenous magnesium sulfate (4 g) was compared with placebo.

Main Outcomes and Measures

The primary outcome was death (stillbirth, death of a live-born infant before hospital discharge, or death after hospital discharge before 2 years' corrected age) or cerebral palsy (loss of motor function and abnormalities of muscle tone and power assessed by a pediatrician) at 2 years' corrected age. There were 36 secondary outcomes that assessed the health of the pregnant individual, infant, and child.

Results

Of the 1433 pregnant individuals enrolled (mean age, 30.6 [SD, 6.6] years; 46 [3.2%] self-identified as Aboriginal or Torres Strait Islander, 237 [16.5%] as Asian, 82 [5.7%] as Māori, 61 [4.3%] as Pacific, and 966 [67.4%] as White) and their 1679 infants, 1365 (81%) offspring (691 in the magnesium group and 674 in the placebo group) were included in the primary outcome analysis. Death or cerebral palsy at 2 years' corrected age was not significantly different between the magnesium and placebo groups (3.3% [23 of 691 children] vs 2.7% [18 of 674 children], respectively; risk difference, 0.61% [95% CI, -1.27% to 2.50%]; adjusted relative risk [RR], 1.19 [95% CI, 0.65 to 2.18]). Components of the primary outcome did not differ between groups. Neonates in the magnesium group were less likely to have respiratory distress syndrome vs the placebo group (34% [294 of 858] vs 41% [334 of 821], respectively; adjusted RR, 0.85 [95% CI, 0.76 to 0.95]) and chronic lung disease (5.6% [48 of 858] vs 8.2% [67 of 821]; adjusted RR, 0.69 [95% CI, 0.48 to 0.99]) during the birth hospitalization. No serious adverse events occurred; however, adverse events were more likely in pregnant individuals who received magnesium vs placebo (77% [531 of 690] vs 20% [136 of 667], respectively; adjusted RR, 3.76 [95% CI, 3.22 to 4.39]). Fewer pregnant individuals in the magnesium group had a cesarean delivery vs the placebo group (56% [406 of 729] vs 61% [427 of 704], respectively; adjusted RR, 0.91 [95% CI, 0.84 to 0.99]), although more in the magnesium group had a major postpartum hemorrhage (3.4% [25 of 729] vs 1.7% [12 of 704] in the placebo group; adjusted RR, 1.98 [95% CI, 1.01 to 3.91]).

Conclusions and Relevance

Administration of intravenous magnesium sulfate prior to preterm birth at 30 to 34 weeks' gestation did not improve child survival free of cerebral palsy at 2 years, although the study had limited power to detect small between-group differences.

Trial Registration

anzctr.org.au Identifier: ACTRN12611000491965.

Factors associated with severe maternal outcome in patients admitted to an intensive care unit in northeastern Brazil with postpartum hemorrhage: a retrospective cohort study

BACKGROUND

Postpartum hemorrhage (PPH) is the leading cause of maternal death worldwide, particularly in low- and middle-income countries; however, the majority of these deaths could be avoided with adequate obstetric care. Analyzing severe maternal outcomes (SMO) has been a major approach for evaluating the quality of the obstetric care provided, since the morbid events that lead to maternal death generally occur in sequence. The objective of this study was to analyze the clinical profile, management, maternal outcomes and factors associated with SMO in women who developed PPH and were admitted to an obstetric intensive care unit (ICU) in northeastern Brazil.

METHODS

This retrospective cohort study included a non-probabilistic, consecutive sample of postpartum women with a diagnosis of PPH who were admitted to the obstetric ICU of the Instituto de Medicina Integral Prof. Fernando Figueira (IMIP) between January 2012 and March 2020. Sociodemographic, biological and obstetric characteristics and data regarding childbirth, the management of PPH and outcomes were collected and analyzed. The frequency of maternal near miss (MNM) and death was calculated. Multiple logistic regression analysis was performed to determine the adjusted odd ratios (AOR) and their 95% confidence intervals (95% CI) for a SMO.

RESULTS

Overall, 136 cases of SMO were identified (37.9%), with 125 cases of MNM (34.9%) and 11 cases of maternal death (3.0%). The factors that remained associated with an SMO following multivariate analysis were gestational age ≤ 34 weeks (AOR = 2.01; 95% CI: 1.12-3.64; p < 0.02), multiparity (AOR = 2.20; 95% CI: 1.10-4.68; p = 0.02) and not having delivered in the institute (AOR = 2.22; 955 CI: 1.02-4.81; p = 0.04).

CONCLUSION

Women admitted to the obstetric ICU with a diagnosis of PPH who had had two or more previous deliveries, gestational age ≤ 34 weeks and who had delivered elsewhere were more likely to have a SMO.

Investigation of Intrapartum Parenteral Magnesium Sulfate as an Independent Risk Factor for Postpartum Hemorrhage Using Quantitative Blood Loss Assessment

BACKGROUND

Magnesium sulfate is used for seizure prophylaxis in preeclampsia and for fetal neuroprotection when delivery is anticipated before 32 weeks of gestation. Existing risk assessment tools for postpartum hemorrhage often identify the use of magnesium sulfate as an intrapartum risk factor. Previous studies examining the association between the use of magnesium sulfate and postpartum hemorrhage have relied largely on qualitative estimates of blood loss rather than quantitative estimates of blood loss.

OBJECTIVE

This study aimed to determine whether intrapartum administration of magnesium sulfate is associated with an increased risk of postpartum hemorrhage using a quantitative blood loss assessment via the use of graduated drapes and weight differences in surgical supplies.

STUDY DESIGN

This case-control study was conducted to test the hypothesis that intrapartum parenteral administration of magnesium sulfate is not independently associated with postpartum hemorrhage. All deliveries at our tertiary-level academic medical center between July 2017 and June 2018 were reviewed. Of note, 2 categories of postpartum hemorrhage were defined: the traditional definition (>500 mL for vaginal delivery and >1000 mL for cesarean delivery) and the contemporary definition (>1000 mL regardless of delivery mode). Statistical analyses using the chi-square test, Fisher exact test, t test, or Wilcoxon rank-sum test were performed to compare the patients who did and did not receive magnesium sulfate concerning the rates of postpartum hemorrhage, pre- and postdelivery hemoglobin level, and rates of blood transfusion.

RESULTS

A total of 1318 deliveries were included, with postpartum hemorrhage rates of 12.2% (traditional definition) and 6.2% (contemporary definition). Multivariate logistic regression did not find the use of magnesium sulfate as an independent risk factor by either definition (odds ratio, 1.44 [95% confidence interval, 0.87-2.38] and 1.34 [95% confidence interval, 0.71-2.54]). The only significant independent risk factor was cesarean delivery, by both definitions (odds ratio, 2.71 [95% confidence interval, 1.85-3.98] and 19.34 [95% confidence interval, 8.55-43.72]).

CONCLUSION

In our study population, intrapartum administration of magnesium sulfate was not found to be an independent risk factor for postpartum hemorrhage. Cesarean delivery was determined as an independent risk factor, consistent with previous reports.

Critical Hypermagnesemia in Preeclamptic Women Under a Magnesium Sulfate Regimen: Incidence and Associated Risk Factors

Magnesium sulfate is used as prophylaxis and treatment of severe preeclampsia/eclampsia, albeit its safety and toxicity are a concern. We designed this study to estimate the incidence of critical hypermagnesemia in severely preeclamptic women under a magnesium sulfate regimen at 8 h following its administration and to identify the associated risk factors as the primary outcomes. Also, secondary outcomes were to compare baseline characteristics, laboratory findings, and maternal-neonatal complications stratified by the baseline serum magnesium (Mg²⁺) in those women, and to assess the degree of agreement between patellar reflex and serum Mg²⁺ concentration 8 h following magnesium sulfate administration. We conducted a retrospective study including severely preeclamptic women receiving magnesium sulfate from June 2016 to May 2021. We enrolled 429 women in the study. Two-hundred sixty-one (60.8%) of the included women developed critical hypermagnesemia. Preeclamptic women with high baseline serum Mg²⁺ concentration demonstrated significantly affected renal functions, hepatic transaminase activities, and low platelet count as well as more reported maternal complications compared to those with low baseline serum Mg². Multivariable logistic regression revealed that a lower gestational age, a higher uric acid concentration, and a higher baseline serum Mg²⁺ concentration were independently associated with an increased risk of critical hypermagnesemia. The agreement between deep tendon reflex assessment and serum Mg²⁺ concentration was slight although not significant. The maternal-neonatal outcomes were non-significant in women with critical hypermagnesemia. More vigilant monitoring through assessment of both serum Mg²⁺ concentration and deep tendon reflex should be considered especially in high-risk women.

Intrapartum magnesium sulfate exposure and obstetric hemorrhage risk

BACKGROUND

The gold standard intrapartum treatment for preeclampsia with severe features is magnesium sulfate in order to provide prophylaxis against eclampsia. However, though magnesium sulfate is known to have a relaxant effect on uterine muscle, there have been variable reports in the literature in regard to the association between magnesium and obstetric hemorrhage (OBH).

OBJECTIVE

We aim to compare OBH incidence in patients with hypertensive disease of pregnancy (HDP) with or without exposure to intrapartum magnesium sulfate.

METHODS

We performed a retrospective cohort study of all deliveries at our institution associated with a diagnosis of hypertensive disease of pregnancy (HDP) (e.g. chronic and gestational hypertension, preeclampsia with or without severe features, eclampsia, or HELLP) from January 1, 2018 to December 31, 2019. The category of HDP diagnosis was determined by a detailed chart review by trained chart abstractors. The primary outcome was total quantitative blood loss (QBL) and the rate of obstetric hemorrhage. Secondary outcomes included a composite of obstetric hemorrhage-related maternal morbidity outcomes (OBH-M), the individual composite components and the incidence of additional hemorrhage-related interventions (e.g. uterotonics and surgical interventions). We also examined the same primary and secondary outcomes in a stratified analysis based on delivery mode (i.e. vaginal deliveries only and cesarean deliveries only).

RESULTS

Of 791 patients with a diagnosis of HDP, 411 patients received magnesium sulfate for eclampsia prophylaxis and 380 patients did not receive magnesium sulfate. For all delivery modes, there was a significantly higher QBL (p < .01), increased rate of OBH (p = .04) and increased OBH-M (p < .01) in deliveries associated with intrapartum exposure to magnesium compared to those without. However, our stratified analysis by delivery mode demonstrated that magnesium-related hemorrhage risk only persisted for vaginal deliveries (QBL p < .01; OBH aOR 1.47, 95% CI: 0.75-2.85; OBH-M aOR 1.47, 95% CI 1.00-7.55) with no significant hemorrhage-related differences among cesareans with or without magnesium exposure (QBL p = .51; OBH aOR 1.45, 95% CI: 0.85-2.47; OBH-M 1.50 95% CI: 0.70-3.23).

CONCLUSION

Intrapartum exposure to magnesium sulfate use was associated with an increase in QBL and risk of OBH-M in vaginal deliveries, but not associated with any hemorrhage-related outcome differences in cesarean deliveries. More research is needed to explore the effects of hypertensive disease, magnesium exposure, and delivery mode on obstetric hemorrhage risk.