A prospective comparison of terbutaline and magnesium for tocolysis. A comparison of magnesium sulfate and terbutaline for the arrest of premature labor. A preliminary report. Prevention of preterm delivery: nifedipine or magnesium sulfate. A comparative study of ketorolac (Toradol) and magnesium sulfate for arrest of preterm labor. Randomized comparison of intravenous nitroglycerin and magnesium sulfate for treatment of preterm labor. Efficacy and side effects of magnesium sulfate and ritodrine as tocolytic agents. The use of ritodrine and magnesium sulfate in the arrest of premature labor. [Treatment of preterm labor with ritodrine]. [Magnesium sulfate in prevention of preterm labor]. A comparison of magnesium sulfate and alcohol for the prevention of premature labor. Oral nicardipine versus intravenous magnesium sulfate for the treatment of preterm labor. Efficacy and safety of indomethacin compared with magnesium sulfate in the management of preterm labor: a randomized study. Comparison of magnesium sulfate, terbutaline and a placebo for inhibition of preterm labor. A randomized study. Evaluation of maternal fluid dynamics during tocolytic therapy with ritodrine hydrochloride and magnesium sulfate. Randomized investigation of magnesium sulfate for prevention of preterm birth. Magnesium sulfate and ritodrine hydrochloride: a randomized comparison. Efficacy and safety of nifedipine versus magnesium sulfate in the management of preterm labor: a randomized study. [Tocolytic therapy with magnesium sulfate and terbutaline for inhibition of premature labor]. Association between the use of antenatal magnesium sulfate in preterm labor and adverse health outcomes in infants. A comparison of ritodrine, terbutaline, and magnesium sulfate for the suppression of preterm labor.
To compare the tocolytic efficacy and side effects of parenteral and oral magnesium and terbutaline.
                Ninety-eight patients in labor between 23-35 weeks were prospectively entered into a controlled trial of intravenous and oral magnesium versus subcutaneous and oral terbutaline. Tocolytic effectiveness was judged by delay of delivery for 48 hours or 1 week, and to 37 weeks or more. The need to change therapy to the alternate drug was identified, as were side effects. Entrance characteristics of the population, initial pelvic examination, and concomitant infection or cervicovaginal isolates were noted. Outcomes included gestational age at delivery, birth weights, and Apgar scores. Outcome analysis was based on initial tocolytic therapy.
                Significantly more patients in the magnesium group delivered at 37 weeks or more: 34 of 46 versus 27 of 52 (P < .05). No significant differences were found for delivery by 48 hours or 1 week. The interval between treatment and delivery was greater for magnesium: 7.1 +/- 3.9 versus 5.0 +/- 3.2 weeks (P < .005). Failure to achieve 37 completed weeks was more often due to obstetric complications than to preterm labor itself. Tocolytic effectiveness was reduced if secondary therapy or re-treatment was required or if the patient had cervical dilatation of 3 cm or greater. Infectious complications were common but were not associated with tocolytic effectiveness. Side effects were more noticeable with oral magnesium and subcutaneous terbutaline.
                For short-term tocolysis, no significant difference was found between magnesium and terbutaline. Magnesium was associated with a higher term delivery rate. Idiopathic preterm labor accounted for only a small part of the overall prematurity in the study population. Intravenous magnesium sulfate and terbutaline were compared as treatments for premature labor. A successful treatment was the arrest of labor for 24 hours. Early treatment was essential for successful management of premature labor. In this study, magnesium sulfate and terbutaline were equally effective in controlling premature labor. Whereas terbutaline was associated with significant alterations in diastolic blood pressure, maternal pulse, fetal heart rate and potassium concentration, magnesium sulfate was not. Magnesium sulfate holds promise as a tocolytic agent, and further clinical study of it is warranted. to establish the efficacy and safety of nifedipine and magnesium sulfate in arresting preterm labor.
                seventy-four patients with singleton pregnancies at 23-36 weeks in preterm labor, were selected randomly to receive either oral nifedipine or intravenous magnesium sulfate.
                both drugs had similar tocolytic efficacy and side effects while nifedipine was faster than magnesium sulfate in arresting uterine contractions (4.8 +/- 4.23 vs. 2.98 +/- 3.03 h) P = 0.04.
                this data suggests that oral nifedipine with the same efficacy, side effects and faster action could be a suitable and more convenient alternative to intravenous magnesium sulfate in arresting preterm labor. We evaluated the efficacy and safety of ketorolac (Toradol).
                In this prospective trial, 88 women in confirmed preterm labor at < or =32 weeks' gestation were randomized to receive magnesium sulfate given as an initial 6 g intravenous bolus followed by continuous infusion therapy (2 to 6 g/hr) or intramuscularly administered ketorolac (60 mg loading dose) followed by 30 mg every 6 hours for a maximum of 24 hours.
                The study groups were similar with respect to age, parity, cervical status, and gestational age on admission. Ketorolac was more rapid (2.71 hr+/-2.16) in the arrest of preterm labor than was magnesium sulfate (6.22 hr+/-5.65). No patient required discontinuance of either drug due to adverse effects. There was no difference in the incidence of neonatal complications between the two groups.
                In gestations with preterm labor at <32 weeks, ketorolac appears to be an appropriate first-line tocolytic agent. To compare the safety and efficacy of high-dose intravenous (IV) nitroglycerin with those of IV magnesium sulfate for acute tocolysis of preterm labor.
                Thirty-one women with preterm labor before 35 weeks' gestation were assigned randomly to IV magnesium sulfate or IV nitroglycerin for tocolysis. Preterm labor was defined as the occurrence of at least two contractions in 10 minutes, with cervical change or ruptured membranes. Acute tocolysis was defined as tocolysis for up to 48 hours. Magnesium sulfate was administered as a 4-g bolus, then at a rate of 2-4 g/h. Nitroglycerin was administered as a 100-microg bolus, then at a rate of 1- to 10-microg/kg/min. The primary outcome measure was achievement of at least 12 hours of successful tocolysis.
                Thirty patients were available for analysis. There were no significant differences in gestational age, cervical dilation, or incidence of ruptured membranes between groups at the initiation of tocolysis. Successful tocolysis was achieved in six of 16 patients receiving nitroglycerin, compared with 11 of 14 receiving magnesium sulfate (37.5 versus 78.6%, P = .033). Tocolytic failures (nitroglycerin versus magnesium sulfate) were due to persistent contractions with cervical change or rupture of previously intact membranes (five of 16 versus two of 14), persistent hypotension (four of 16 versus none of 14), and other severe side effects (one of 16 versus one of 14). Maternal hemodynamic alterations were more pronounced in patients who received nitroglycerin, and 25% of patients assigned to nitroglycerin treatment had hypotension requiring discontinuation of therapy.
                Tocolytic failures were more common with nitroglycerin than with magnesium sulfate. The hemodynamic alterations noted in patients receiving nitroglycerin, including a 25% incidence of persistent hypotension, might limit the usefulness of IV nitroglycerin for the acute tocolysis of preterm labor. Ritodrine as the first-line drug in the treatment of established preterm labor has been supplanted in some centers by magnesium sulfate. To assess the relative efficacy and rates of side effects of these two agents, 120 patients were randomly assigned to receive one of these two drugs. Patients were included if they had intact membranes and met strict criteria for the definition of labor. In both groups excellent outcome was achieved, with 96.3% and 92.3% of patients receiving ritodrine and magnesium sulfate, respectively, obtaining a delay in delivery of greater than 48 hours. Side effects were comparable in both groups, although they tended to be more serious in the patients receiving ritodrine. In patients receiving both drugs together, the rate of side effects was 77% without a demonstrable benefit over a single agent. We conclude that ritodrine and magnesium sulfate are tocolytics of comparable efficacy and when used aggressively are highly successful in delaying delivery. Sixty-seven cases of premature labor (48 with unruptured and 19 with ruptured membranes) were treated with ritodrine or magnesium sulfate infusion supplemented with oral ritodrine in case of initial success. Both treatment regimens were found effective irrespective of maternal age, parity, ethnic background and number of previous abortions. The study supports the clinical experience indicating that early administration of tocolytic agents is highly successful in arresting premature labor and preventing its dire consequences. To investigate the treatment of preterm labor with the beta-adrenergic agonist ritodrine.
                126 women with preterm labor were randomly assigned to intravenous infusion of ritodrine or magnesium sulfate treatment. Using minimal effective dosage for inhibition of uterine activity, terminating therapy on time, and repeating the i.v. infusion if contraction restarted were the strategy for treatment.
                Ritodrine was significantly more effective both in the treating period for suppression of contraction (2.33 +/- 0.63 hr for initiation of inhibiting uterine activity, 9.38 +/- 3.88 days of accumulative treating period) and prolongation of gestation (4.81 +/- 2.83 wks) than that of the magnesium sulfate (P < 0.001, 0.005 and 0.01 respectively), and had a term labor of 73.44%. There was no serious cardiac and pulmonary complications in the ritodrine group.
                The present study has shown that ritodrine as a tocolytic agent is highly effective for the management of preterm labor and relative safe for mother and fetus. To observe the efficacy of magnesium sulfate in the treatment of preterm labor, 65 uncomplicated cases of preterm labor between 28 and 36 weeks of gestation were studied prospectively during Sep. 1988-May 1991. They were divided into two groups randomly. 30 cases were treated with magnesium sulfate and 35 cases with barbiturates or bed rest. The prevention of delivery for at least 48 hours after the initiation of therapy was achieved in 23 of the 30 cases (76.67%) of the magnesium sulfate group and in 3 of the 35 cases (8.57%) in the control group. Delay of more than 7 days was achieved in 17 of the 30 cases (56.67%) and in 2 of the 35 cases (5.71%). The postponement of delivery between the two groups. There was highly significantly difference (P less than 0.01). There was a significant correlation of cervical dilation at the onset of treatment to success of controlling preterm labor. In the magnesium sulfate group, the mean magnesium level to achieve tocolysis was 2.8 +/- 0.35 mmol/L (mean +/- s). The side effects to the mothers, fetus, and the neonates were mild and not prominent.(ABSTRACT TRUNCATED AT 250 WORDS) In travenous magnesium sulfate and alcohol were compared as treatments for premature labor. A successful treatment was the absence of contractions for a 24 hour interval. Early treatment was found to be essential for successful management of premature labor. There is a significant correlation of cervical dilatation at the onset of treatment to success at controlling premature labor. There was no statistically significant relation to weeks of gestation or parity to success at controlling premature labor. In this study magnesium sulfate was the better agent for controlling premature labor. The aim of this study was to compare the efficacy and safety of oral nicardipine in acute therapy for preterm labor with those of parenteral magnesium sulfate.
                Patients between 24 and 34 weeks' gestation with documented preterm labor were randomly assigned to receive oral nicardipine (n = 57) or intravenous magnesium sulfate (n = 65) as initial tocolytic therapy. Patients in the nicardipine group received a 40-mg loading dose and then 20 mg every 2 hours as needed to stop contractions (total 80 mg). Patients in the magnesium sulfate group received a 6-g bolus followed by 2 to 4 g/h to provide uterine quiescence. Patients could be switched to another tocolytic regimen if they continued to have contractions after 6 hours of therapy. The main outcome variables examined were time to uterine quiescence, time gained in utero, recurrence of preterm labor, failure of tocolysis, and pertinent maternal and neonatal outcomes.
                There were no significant differences in maternal demographic characteristics between the groups. Among patients who responded with uterine quiescence within 6 hours, there was a significant decrease in the time to uterine quiescence in the nicardipine group (P <.01). Patients in the magnesium sulfate group were more likely to have recurrence of preterm labor necessitating further tocolytic attempts (P =.048). The patients in the magnesium sulfate group had more adverse side effects, mainly nausea and vomiting (P =.004). There were no differences in birth weight, estimated gestational age at delivery, or neonatal complications between the 2 groups.
                Oral nicardipine is an effective, safe, and well-tolerated tocolytic agent. In this prospective clinical trial patients randomly assigned to receive oral nicardipine had arrest of preterm labor more rapidly than did those randomly assigned to receive parenteral magnesium sulfate. Patients who received magnesium sulfate were more likely to have adverse medication effects and recurrent preterm labor. Our purpose was to evaluate the relative efficacy and safety of indomethacin versus magnesium sulfate in the management of preterm labor in pregnancies < 32 weeks of gestation.
                Eligible patients admitted with singleton pregnancies and idiopathic preterm labor between August 1988 and October 1989 were randomized by sealed envelopes to receive either indomethacin or intravenous magnesium sulfate.
                Of 101 eligible patients 49 were randomized to receive indomethacin. The two study groups were similar in regard to a number of entry variables, including gestational age, cervical examination, and contraction frequency. Indomethacin was as effective as magnesium sulfate in delaying delivery > 48 hours, 90% versus 85%, and together with oral terbutaline in extending the gestation, 22.9 versus 22.7 days. Tocolysis with magnesium sulfate was discontinued in eight (15%) patients because of maternal side effects, in contrast to none in the indomethacin group, p < 0.05.
                For gestations < 32 weeks indomethacin may be considered an appropriate alternative to magnesium sulfate as a first-time tocolytic agent. Magnesium sulfate has been recommended as a safe and effective agent for inhibiting preterm labor. Its reported adequacy as a tocolytic agent, however, has not been substantiated by randomized, controlled trials. To assess the efficacy of magnesium sulfate, we initiated a prospective, randomized study comparing the capabilities of magnesium sulfate, terbutaline and a placebo (5% dextrose in lactated Ringer's solution) for labor inhibition. The study population consisted of 54 patients between 26 and 34 weeks of gestation and in preterm labor. The diagnosis of labor was made if, following hydration, persistent uterine contractions occurred at a frequency of at least three in a ten-minute period and cervical examination suggested active labor. Success was defined as postponement of delivery for at least 48 hours after initiation of therapy. Despite a trend toward increased efficacy in the terbutaline group there were no significant differences between the three treatment groups with regard to capability of delaying delivery at least 48 hours. Also, there were no significant differences between the groups with regard to gestational age at delivery, birth weight and neonatal survival. The fact that delivery occurred in less than 48 hours of approximately one-half the patients under the best of circumstances emphasizes the need for more effective techniques for the inhibition of preterm labor and the need for a better understanding of the mechanisms involved in the initiation of preterm labor. The purpose of the study was to observe and compare the effects of ritodrine hydrochloride and magnesium sulfate on maternal fluid dynamics.
                Fourteen women in preterm labor were prospectively studied during tocolytic therapy with either ritodrine hydrochloride or magnesium sulfate. The cardiovascular and renal effects of a pretreatment crystalloid infusion were compared with those observed during tocolytic therapy. Profile analysis and repeated measures of variance were used to analyze the data.
                Ritodrine hydrochloride was associated with decreased colloid osmotic pressure, hematocrit, and serum proteins and increased maternal and fetal heart rates. Arginine vasopressin levels increased during the first 2 hours of therapy, then returned to baseline. Sodium excretion was reduced and there was marked fluid retention. Intravenous magnesium sulfate also resulted in a reduction of colloid osmotic pressure, but hematocrit, serum protein concentration, arginine vasopressin, maternal and fetal heart rates, and mean arterial pressure were minimally affected. Sodium excretion increased to a maximum at 6 to 8 hours of treatment, then returned to baseline. A positive fluid balance was also noted in magnesium sulfate-treated patients but to a lesser degree than with ritodrine.
                Sodium retention appears to be the primary cause of plasma volume expansion in ritodrine-treated patients, whereas volume expansion during magnesium sulfate therapy is probably related to intravenous overhydration. In the absence of risk factors for pulmonary capillary membrane injury, available evidence supports volume overload as the principal mechanism for pulmonary edema during tocolytic therapy. One hundred fifty-six women with preterm labor between 24 and 34 weeks' gestation were randomized to receive either intravenous magnesium sulfate or no tocolytic therapy. Magnesuim sulfate infusions of up to 3 gm/hr were used in 76 pregnancies and resulted in a mean serum magnesium concentration of 5.5 +/- 1.4 mEq/L (mean +/- SEM). Compared with 80 control pregnancies, magnesium sulfate tocolysis had no significant effect on duration of gestation, birth weight, neonatal morbidity, and perinatal mortality. We conclude that clinically safe infusions of magnesium sulfate are ineffective when used to prevent preterm birth. The efficacy of magnesium sulfate was analyzed in relation to ritodrine hydrochloride. Patients presenting in preterm labor between 20 and 35 weeks' gestation were prospectively randomized. Tocolysis was achieved for more than 72 hours in 35 of 40 cases (88%) where magnesium sulfate was administered and 31 of 39 cases (79%) in which ritodrine hydrochloride was infused. Delay of greater than or equal to 7 days was achieved in 75% and 72% of cases, respectively. The mean dosage to achieve tocolysis was 4.5 gm/hr, in the magnesium sulfate group and 210.0 micrograms/hr in ritodrine hydrochloride-treated patients. The mean magnesium level to achieve tocolysis was 6.60 mg/dl. Side effects in the two groups were similar in number but less alarming in the magnesium sulfate group. Magnesium sulfate was found to be easy to administer and clinically efficacious. Its tocolytic action was found to be dose dependent and drug concentrations are easily determined. On the basis of this work and data from other investigators, magnesium sulfate should be used as the first line of tocolytic therapy with ritodrine hydrochloride as its pharmacologic backup. Our purpose was to establish the efficacy and safety of nifedipine versus magnesium sulfate in arresting preterm labor and the efficacy of nifedipine versus terbutaline in preventing recurrent labor.
                Singleton pregnancies at < 34 weeks in preterm labor were randomized to either oral nifedipine or intravenous magnesium sulfate. In case of tocolysis failure ritodrine was added. After labor was arrested, the patients in the nifedipine group were maintained on oral nifedipine, and those in the magnesium sulfate group were treated with oral terbutaline until completing 34 weeks.
                Of 100 patients 80 were considered eligible, of whom 39 were randomized to the nifedipine group. Both groups were comparable in terms of a number of entry variables, including cervical examination, contraction frequency, and gestational age. Both drugs were equally effective in arresting labor and delaying delivery > 48 hours, 92% versus 93%. Both study groups had a similar incidence of side effects, although four (10%) of magnesium sulfate-treated patients required drug discontinuation because of severe symptoms. Nifedipine was as effective as terbutaline in preventing recurrent labor, 26% versus 24%, and in achieving a gestation > 34 weeks, 62% versus 68%.
                Oral nifedipine is as effective as magnesium sulfate and terbutaline in arresting and preventing idiopathic preterm labor. Magnesium sulfate has been recommended as a safe and effective tocolytic agent. However has not been substantiated by randomized, controlled trials. To assess the efficacy of magnesium sulfate, we initiated prospective randomized study competing the capabilities of magnesium sulfate and terbutaline for labor inhibition. The study population consisted of 30 patients (15 patients with terbutaline and 15 patients with magnesium sulfate) between 28 and 36 weeks of gestation and in preterm labor. One patient in terbutaline group was excluded of the study because we found a severe fetal distress. The diagnosis of labor was made if, persistent uterine contractions occurred at a frequency of at last three in a team-minute period and cervical examination suggested active labor. Success was defined as postponement of delivery for at least 48 hours after initiation of therapy. Despite a trend toward increased efficacy in the terbutaline group (tocolytic Bishop grade and its success) there were no significant differences between the two treatment groups with regard to capability of delaying delivery at least 48 hours. Although there were significant differences for terbutaline regard the tocolysis time. For all these reasons, the efficacy between both groups of treatment is similar, and in a future cases, will be necessary to choose the better agent for every case to study. The purpose of this study was to determine whether the use of antenatal magnesium sulfate prevents adverse outcomes (neonatal intraventricular hemorrhage, periventricular leucomalacia, death, and cerebral palsy).
                In a controlled trial, we randomized mothers in preterm labor to magnesium sulfate, "other" tocolytic, or placebo. At delivery, umbilical cord blood was collected for the later determination of serum ionized magnesium levels. Neonatal cranial ultrasound scans were obtained periodically for the diagnosis of intraventricular hemorrhage and periventricular leucomalacia. Among survivors, the diagnosis of cerebral palsy was made at age 18 months.
                Children with adverse outcomes had higher umbilical cord magnesium levels at delivery. In regression models that controlled for confounders, which included very low birth weight, magnesium remained a significant risk factor (adjusted odds ratio, 3.7; 95% CI, 1.1-11.9; P =.03).
                Contrary to original hypotheses, this randomized trial found that the use of antenatal magnesium sulfate was associated with worse, not better, perinatal outcome in a dose-response fashion. Ritodrine, terbutaline, and magnesium sulfate have all been used in the United States as tocolytic drugs. Studies have shown each of these drugs to be effective in suppressing preterm labor. The current study was undertaken in order to compare their relative safety and efficacy and to evaluate the effectiveness of a second drug when the first-used drug failed to stop contractions. No differences in efficacy could be demonstrated between the drugs; however, there was a marked difference in the incidence of maternal side effects. Because of an unacceptable level of side effects, we have stopped the use of terbutaline at our institution.
Magnesium sulphate is ineffective at delaying birth or preventing preterm birth, and its use is associated with an increased mortality for the infant. Any further trials should be of high quality, large enough to assess serious morbidity and mortality, compare different dose regimens, and provide neurodevelopmental status of the child.