The effects of magnesium therapy on the duration of labor

Hall, David G.; McGaughey, Harry S.; Corey, E. L.; Thornton, W.Norman

doi:10.1016/0002-9378(59)90635-0

Cited by 75 publications

(10 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, tension induced by PGF,, in stem villous and by vasopressin in intramyometrial arteries was decreased by mcreasing concentrations of Mg'+ (1.5-6.0 mM). Apparently the effects of increasing concentrations of Mg2+ include relaxation of both fetal and maternal uteroplacental arteries, in addition to relaxation of the myometrium (Hall 1959, Spisso et al 1982. However, the haemodynamic effects of such treatment depend on the overall systemic response.…”

Section: Discussionmentioning

confidence: 99%

Effects of magnesium on isolated human fetal and maternal uteroplacental vessels

Skajaa¹,

Forman²,

Andersson³

1990

Acta Physiologica Scandinavica

View full text Add to dashboard Cite

The effects of Mg2+ were studied in human umbilical arteries, stem villous arteries and maternal intramyometrial arteries. The vessels were dissected and mounted in organ baths, and isometric tension was recorded. In all fetal preparations investigated, Mg2+ (0.5-6.0 mM) in a concentration-related way decreased pD2 values for prostaglandin F2 alpha responses. The maximum response to prostaglandin F2 alpha was depressed in umbilical arteries, but remained unaffected in stem villous artery preparations. In stem villous arteries pretreated in Ca2(+)-free medium, increasing concentrations of Mg2+ markedly depressed the response to Ca2+ after stimulation with K+ or prostaglandin F2 alpha, suggesting that Mg2+ inhibited transmembrane calcium influx and interfered with intracellular calcium effects. In both stem villous and intramyometrial arteries, increasing concentrations of Mg2+ increased EC50 values for responses to K+, whereas Emax values were unaffected. Mg2+ produced relaxation of agonist-induced contractions by up to 60% in stem villous arteries and up to 40% in intramyometrial artery preparations. The relaxant effect of Mg2+ did not seem to be mediated through the endothelium or through changes in the synthesis of prostanoids, since endothelial disruption and treatment with indomethacin left the responses to Mg2+ unaffected. Relaxation of vessels important for resistance regulation in the human uteroplacental vascular bed may be of benefit when uteroplacental blood flow is impaired, and the present results support the established use of magnesium sulphate in the treatment of pre-eclampsia.

show abstract

Section: Discussionmentioning

confidence: 99%

Effects of magnesium on isolated human fetal and maternal uteroplacental vessels

Skajaa¹,

Forman²,

Andersson³

1990

Acta Physiologica Scandinavica

View full text Add to dashboard Cite

show abstract

“…17 This in turn inhibits smooth muscle contractility. The tocolytic properties of magnesium ions were first reported in 1959 by Hall et al, 18 who described prolongation of labor in patients treated with magnesium sulfates. Its mechanism of action has been clearly elucidated, and an antagonism to calcium ion binding to the sarcoplasmic reticulum may be the most probable mode of action of the agent in the treatment of preterm labor.…”

Section: Discussionmentioning

confidence: 97%

Influence of Lipopolysaccharide on the Uterine Contraction Inhibitory Effects of Tocolytic Agents in Pregnant Mice

et al. 2007

View full text Add to dashboard Cite

The study was undertaken to investigate the influence of lipopolysaccharide (LPS) on the uterine contraction inhibitory effects of tocolytic agents such as ritodrine, magnesium, and diethylamine/nitric oxide (DEA/NO), and on prostaglandin (PG) E2 and nitric oxide (NO) metabolite (NOx) production in pregnant mice at midgestation. Pregnant C57BL mice on day 14 of gestation were sacrificed 6 hours after intraperitoneal injection of LPS (400 mug/kg) or vehicle. Uterine rings were equilibrated in Krebs-Henseleit solution (37 degrees C) bubbled with 20% O (2) and 5% CO (2) (pH ~7.4) for sampling and isometric tension recording. The concentration levels of PGE2 and NOx in the solution were determined. Changes of spontaneous contractile activity in response to cumulative concentrations of ritodrine, magnesium, and the NO donor, DEA/NO, from the baseline were determined. Integral contractile activity over 10 minutes at each concentration was calculated and expressed as percentage change from basal activity. Statistical analysis was performed using one-way analysis of variance (ANOVA) followed by the Dunnett test (significance: P < 0.05). LPS treatment significantly increased the production levels of PGE2 and NOx (from 66.8 +/- 6.7 pg/g tissue to 147.0 +/- 29.0, from 51.0 +/- 5.4 pmol/2 muL/g tissue to 98.0 +/- 16.2, respectively), P < 0.05). Ritodrine, magnesium, and DEA/NO inhibited spontaneous contractions concentration dependently in uterine rings from both LPS-treated and -untreated animals. Treatment with LPS significantly attenuated the maximal inhibition induced by DEA/NO in uterine rings from pregnant mice. LPS significantly suppressed the uterine contraction inhibitory effects of ritodrine at 10 (-8) M concentrations and of magnesium at 4.2 mmol concentration ( P < 0.05). We concluded that the effects of ritodrine and magnesium may be reduced under inflammatory conditions because LPS increases the production levels of PGE2 and NOx, which cause increased spontaneous contractions of the uterine myometrium. Therefore, when uterine contractions are not controlled by tocolytics in pregnant patients with preterm labor associated with inflammation, labor induction or pregnancy termination may become significant options in clinical practice.

show abstract

“…It is thought to involve modulation of calcium uptake, binding and distribution within myometrial smooth muscle cells, resulting in decreased contractility and generalized muscle relaxation. Magnesium sulfate has been shown to inhibit calcium-induced uterine contractions [55,56]. However, high serum concentrations of magnesium 4 to 8 mEq/L (roughly equivalent to 5 to 7 mg/dl) are necessary to elicit a reduction in uterine contractility.…”

Section: Molecule Mode Of Administration and Mechanism Of Actionmentioning

confidence: 99%

Preterm Labour: An Overview of Current and Emerging Therapeutics

Schwarz¹,

Page²

2003

CMC

View full text Add to dashboard Cite

Preterm labour is a major cause of perinatal mortality and morbidity. However, during the past 40 years of clinical studies and despite the use of multiple therapeutic agents, the rate of preterm birth has not drastically declined. In 1991, it was estimated that in the US approximately 116,000 women admitted with acute episodes of preterm labour were treated each year with ritodrine, which is the first drug approved by the US FDA and still remains the standard therapy for treating preterm labour. Ritodrine (Yutopar( trade mark )) stimulates the beta(2)-adrenergic receptor throughout the body, causing an inhibitory action in different tissues that, among other side effects, also leads to an attenuation of uterine contractility. More recently, a new therapeutic agent, atosiban (Tractocile( trade mark )), a peptidic oxytocin receptor antagonist, has been introduced to the market. However, the use of the various pharmacological agents to treat preterm labour remains restricted, due to lack of uterine selectivity, low efficacy and potentially serious side effects for the mother or the foetus. Therefore, there is an urgent need to develop drugs with myometrial selectivity that would allow long-lasting inhibition of labour and prolong pregnancy up to a stage when good foetal maturation raises the chances of survival. One of the major obstacles hampering the development of new therapeutic agents is the marked inter-species difference in terms of preterm labour physiology, which complicates the preclinical evaluation of new candidate molecules in animal models of disease. In this review, the authors will provide a comprehensive update of past, current and new approaches for the management of preterm labour, including beta(2)-adrenergic agonists, calcium channel blockers, oxytocin antagonists, prostaglandin antagonists and other potential therapeutics. For each of the therapies used today, the review will cover the mechanism of action, benefit and adverse effects, and discuss the promise and potential benefits of new emerging therapeutic agents.

show abstract

The effects of magnesium therapy on the duration of labor

Cited by 75 publications

References 11 publications

Effects of magnesium on isolated human fetal and maternal uteroplacental vessels

Effects of magnesium on isolated human fetal and maternal uteroplacental vessels

Influence of Lipopolysaccharide on the Uterine Contraction Inhibitory Effects of Tocolytic Agents in Pregnant Mice

Preterm Labour: An Overview of Current and Emerging Therapeutics

Contact Info

Product

Resources

About