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The Cochrane Database of Systematic... Feb 2014Preterm birth is a major contributor to perinatal mortality and morbidity worldwide. Tocolytic agents are drugs used to inhibit uterine contractions. Betamimetics are... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Preterm birth is a major contributor to perinatal mortality and morbidity worldwide. Tocolytic agents are drugs used to inhibit uterine contractions. Betamimetics are tocolytic agents that have been widely used, especially in resource-poor countries.
OBJECTIVES
To assess the effects of betamimetics given to women with preterm labour.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 December 2013) and reference lists of retrieved studies.
SELECTION CRITERIA
Randomised controlled trials of betamimetics, administered by any route or any dose, in the treatment of women in preterm labour where betamimetics were compared with other betamimetics, placebo or no treatment.
DATA COLLECTION AND ANALYSIS
Two review authors assessed risk of bias and extracted the data independently.
MAIN RESULTS
Twenty-eight trials were assessed as eligible for inclusion in the review, but eight did not report any outcome data relevant to the review. Results are based on the 20 trials that contributed data.Twelve trials, involving 1367 women, compared betamimetics with placebo. Betamimetics decreased the number of women in preterm labour giving birth within 48 hours (average risk ratio (RR) 0.68, 95% confidence interval (CI) 0.53 to 0.88, 10 trials, 1209 women). There was a decrease in the number of births within seven days (average RR 0.80; 95% CI 0.65 to 0.98, five trials, 911 women) but there was no evidence of a reduction in preterm birth (before 37 weeks' gestation) (RR 0.95; 95% CI 0.88 to 1.03, 10 trials, 1212 women). No benefit was demonstrated for betamimetics for perinatal death (RR 0.84; 95% CI 0.46 to 1.55, 11 trials, 1332 infants), or neonatal death (RR 0.90; 95% CI 0.27 to 3.00, six trials, 1174 infants). No significant effect was demonstrated for respiratory distress syndrome (RR 0.87; 95% CI 0.71 to 1.08, eight trials, 1239 infants). A few trials reported on cerebral palsy, infant death and necrotising enterocolitis; no significant differences between groups were identified for any of these outcomes. Betamimetics were significantly associated with the following outcomes: withdrawal from treatment due to adverse effects; maternal chest pain; dyspnoea; palpitation; tremor; headaches; hypokalaemia; hyperglycaemia; nausea or vomiting; nasal stuffiness; and fetal tachycardia.Nine trials compared different types of betamimetics. Other betamimetics were compared with ritodrine in five trials (n = 948). Other comparisons were examined in single trials: hexoprenaline compared with salbutamol (n = 140), slow versus moderate release salbutamol (n = 52) and salbutamol compared with terbutaline (n = 200). Trials were small, varied, and of insufficient quality to delineate any consistent patterns of effect.
AUTHORS' CONCLUSIONS
Betamimetics help to delay birth, which may give time to allow women to be transferred to tertiary care or to complete a course of antenatal corticosteroids. However, multiple adverse effects must be considered. The data are too few to support the use of any particular betamimetic.
Topics: Adrenergic beta-Agonists; Female; Fenoterol; Hexoprenaline; Humans; Obstetric Labor, Premature; Pregnancy; Premature Birth; Randomized Controlled Trials as Topic; Ritodrine; Terbutaline; Tocolytic Agents
PubMed: 24500892
DOI: 10.1002/14651858.CD004352.pub3 -
BMC Pregnancy and Childbirth Apr 2024Some studies have compared the efficacy of nifedipine with that of other tocolytic drugs in the treatment of preterm labor, but the reported results are conflicting. (Meta-Analysis)
Meta-Analysis Comparative Study
BACKGROUND
Some studies have compared the efficacy of nifedipine with that of other tocolytic drugs in the treatment of preterm labor, but the reported results are conflicting.
OBJECTIVE
To compare the efficacy of nifedipine with that of ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor.
METHODS
In this systematic review and meta-analysis, PubMed/MEDLINE, Scopus, Clarivate Analytics Web of Science, and Google Scholar were searched until April 3,2024 using predefined keywords. Randomized controlled trials (RCTs) and clinical trials that compared the efficacy of nifedipine with that of ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor were included. Two authors independently reviewed the articles, assessed their quality and extracted the data. The quality of the included RCTs based on the Cochrane Risk of Bias Tool 1 for clinical trial studies. The risk difference (RD) with the associated 95% confidence interval (CI) was calculated. A forest plot diagram was used to show the comparative point estimates of nifedipine and other tocolytic drugs on the prevention of preterm labor and their associated 95% confidence intervals based on the duration of pregnancy prolongation. Study heterogeneity was evaluated by the I index, and publication bias was evaluated by Egger's test.
RESULTS
Forty studies enrolling 4336 women were included. According to our meta-analysis, there was a significant difference in the prolongation of preterm labor within the first 48 h between the nifedipine group and the nitroglycerine group (RD, -0.04; 95% CI, -0.08 to -0.00; I: 32.3%). Additionally, there were significant differences between nifedipine and ritodrine (RD, 0.11; 95% CI, 0.02 to 0.21; I, 51.2%) for more than one week RD, 0.10; 95% CI, 0.03 to 0.19; I, 33.2%) and for 34 weeks and more. The difference between nifedipine and magnesium sulfate was not significant in any of the four time points.
CONCLUSIONS
Considering the superiority of nifedipine over ritodrine and nitroglycerine and its similar efficacy to magnesium sulfate for tocolysis, it seems that the side effects of these options determine the first drug line.
Topics: Humans; Nifedipine; Female; Pregnancy; Obstetric Labor, Premature; Magnesium Sulfate; Ritodrine; Tocolytic Agents; Nitroglycerin; Treatment Outcome; Randomized Controlled Trials as Topic
PubMed: 38664622
DOI: 10.1186/s12884-024-06497-w -
The Cochrane Database of Systematic... Jan 2014Prematurity is not only the leading cause of perinatal morbidity and mortality but is associated with long-term impairment. Studies of various tocolytic agents have... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Prematurity is not only the leading cause of perinatal morbidity and mortality but is associated with long-term impairment. Studies of various tocolytic agents have shown mixed results with little effect in improving pregnancy duration and insufficient data to confirm a definite beneficial effect on neonatal morbidity or mortality. Progesterone is known to have an inhibitory effect on uterine contractility and is thought to play a key role in the maintenance of pregnancy until term.
OBJECTIVES
To determine if the use of progestational agents is effective as a form of treatment or co-treatment for women with threatened or established preterm labour with intact membranes.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2013), CENTRAL (The Cochrane Library 2013, Issue 10), MEDLINE (1966 to August 31 2013) and Embase (1974 to 31 August 2013). We checked the reference lists of all included studies to identify any additional studies and communicated with authors and the pharmaceutical industry.
SELECTION CRITERIA
Randomised controlled trials that compared progestational agents, given either alone or in combination with other tocolytics, with a control group receiving another tocolytic, placebo or no treatment, for the treatment of preterm labour.
DATA COLLECTION AND ANALYSIS
Two review authors independently extracted data and assessed trial quality.
MAIN RESULTS
Eight studies were included in this review, involving 563 women, but only seven studies, involving 538 women, contributed data for analyses. There are some data suggesting that the use of progestational agents results in a reduction of preterm deliveries at less than 37 weeks of gestation and an increase in birthweight. The use of a progestational agent may also reduce the frequency of uterine contractions, prolong pregnancy and attenuate the shortening of cervical length. However, the analysis was limited by the relatively small number of available studies. The power of the meta-analysis was also limited by the varying types, dosages and routes of administration of progesterone.
AUTHORS' CONCLUSIONS
There is insufficient evidence to advocate progestational agents as a tocolytic for women presenting with preterm labour.
Topics: Female; Humans; Obstetric Labor, Premature; Pregnancy; Progesterone; Progestins; Randomized Controlled Trials as Topic; Ritodrine; Tocolytic Agents
PubMed: 24482121
DOI: 10.1002/14651858.CD006770.pub3 -
The Cochrane Database of Systematic... Dec 2012Some women who have threatened to give birth prematurely, subsequently settle. They may then take oral tocolytic maintenance therapy to prevent preterm birth and to... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Some women who have threatened to give birth prematurely, subsequently settle. They may then take oral tocolytic maintenance therapy to prevent preterm birth and to prolong gestation.
OBJECTIVES
To assess the effects of oral betamimetic maintenance therapy after threatened preterm labour for preventing preterm birth.
SEARCH METHODS
We updated the search of the Cochrane Pregnancy and Childbirth Group's Trials Register on 9 November 2012.
SELECTION CRITERIA
Randomised controlled trials comparing oral betamimetic with alternative tocolytic therapy, placebo or no therapy, for maintenance following treatment of threatened preterm labour.
DATA COLLECTION AND ANALYSIS
Two review authors independently applied the selection criteria and carried out data extraction and quality assessment of studies.
MAIN RESULTS
We did not identify any new trials from the updated search so the results remain unchanged as follows.We included 13 randomised controlled trials (RCTs) with a total of 1551 women. We found no differences for admission to the neonatal intensive care unit when betamimetics were compared with placebo (risk ratio (RR) 1.28, 95% confidence interval (CI) 0.68 to 2.41; two RCTs of terbutaline with 2600 women) or with magnesium (RR 0.80, 95% CI 0.43 to 1.46; one RCT of 137 women). The rate of preterm birth (less than 37 weeks) showed no significant difference in six RCTs, four comparing ritodrine with placebo/no treatment and two comparing terbutaline with placebo/no treatment (RR 1.11, 95% CI 0.91 to 1.35; 644 women). We observed no differences between betamimetics and placebo, no treatment or other tocolytics for perinatal mortality and morbidity outcomes. Some adverse effects such as tachycardia were more frequent in the betamimetics groups than the groups allocated to placebo, no treatment or another type of tocolytic.
AUTHORS' CONCLUSIONS
Available evidence does not support the use of oral betamimetics for maintenance therapy after threatened preterm labour.
Topics: Administration, Oral; Adrenergic beta-2 Receptor Agonists; Female; Humans; Indomethacin; Magnesium Compounds; Maintenance Chemotherapy; Obstetric Labor, Premature; Pregnancy; Randomized Controlled Trials as Topic; Ritodrine; Terbutaline; Tocolytic Agents
PubMed: 23235600
DOI: 10.1002/14651858.CD003927.pub3 -
The Cochrane Database of Systematic... Jul 2014Preterm birth represents the single largest cause of mortality and morbidity for newborns and a major cause of morbidity for pregnant women. Tocolytic agents include a... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Preterm birth represents the single largest cause of mortality and morbidity for newborns and a major cause of morbidity for pregnant women. Tocolytic agents include a wide range of drugs that can inhibit labour to prolong pregnancy. This may gain time to allow the fetus to mature further before being born, permit antenatal corticosteroid administration for lung maturation, and allow time for intra-uterine transfer to a hospital with neonatal intensive care facilities. However, some tocolytic drugs are associated with severe side effects. Combinations of tocolytic drugs may be more effective over single tocolytic agents or no intervention, without adversely affecting the mother or neonate.
OBJECTIVES
To assess the effects on maternal, fetal and neonatal outcomes of any combination of tocolytic drugs for the treatment of preterm labour when compared with any other treatment, no treatment or placebo.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2014) and reference lists of retrieved studies.
SELECTION CRITERIA
We included randomised controlled trials comparing a combination of tocolytic agents, administered by any route or any dose, for inhibiting preterm labour versus any other treatment (including other combinations of tocolytics or single tocolytics), no intervention or placebo.
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed study reports for eligibility, carried out data extraction and assessed risk of bias.
MAIN RESULTS
Eleven studies met our inclusion criteria. Two studies did not report any outcome data relevant to the review, so the results of the review are based on nine trials that contributed data. Primary outcomes were perinatal mortality, serious maternal or infant outcomes, adverse drug reactions, birth before 48 hours of trial entry, birth before 34 weeks' gestation and preterm neonates delivered without a full course of antenatal steroids completed 24 hours before birth. The quality of evidence in included trials was mixed; only three of the trials were placebo controlled.The included trials examined seven different comparisons: intravenous (IV) ritodrine plus oral or IV magnesium (sulphate or gluconate) versus IV ritodrine alone (three trials, 231 women); IV ritodrine plus indomethacin suppositories versus IV ritodrine alone (one trial, 208 women); IV ritodrine plus vaginal progesterone versus IV ritodrine alone (one trial, 83 women); IV hexoprenaline sulphate plus IV magnesium hydrochloride versus IV hexoprenaline sulphate alone (one trial, 24 women); IV fenoterol plus oral naproxen versus IV fenoterol alone (one trial, 72 women); oral pentoxifylline plus IV magnesium sulphate plus IV fenoterol versus IV magnesium sulphate plus IV fenoterol (one trial, 125 women); and, IV terbutaline plus oral metoprolol versus IV terbutaline alone (one trial, 17 women). Few studies with small numbers of women were available for each comparison, hence very little data were pooled in meta-analysis. In all trials, not many of the primary outcomes were reported.Three trials examined intravenous (IV) ritodrine plus IV or oral magnesium (sulphate or gluconate) compared with IV ritodrine alone. One study, with 41 women, reported more adverse drug reactions in the group receiving the combined tocolytics (risk ratio (RR) 7.79, 95% confidence interval (CI) 1.11 to 54.80). Two trials reported discontinuation of therapy due to severe side effects (results were not combined due to high statistical heterogeneity, I² = 83%); one trial reported increased severe side effects in the group receiving IV ritodrine alone (RR 7.79, 95% CI 1.11 to 54.80, 41 women); in the other trial there was no clear difference between groups (RR 0.23, 95% CI 0.03 to 1.97, 107 women). Other primary outcomes were not reported.One trial assessed IV ritodrine plus indomethacin suppositories versus IV ritodrine alone. There were no significant differences between groups for perinatal mortality or serious neonatal morbidity. Results for other primary outcomes were not reported.There were no significant differences between groups receiving IV ritodrine plus vaginal progesterone compared with IV ritodrine alone for most outcomes reported, although the latency period (time from recruitment to delivery) was increased in the group receiving the combination of tocolytics.For other combinations of tocolytic agents, primary outcomes were rarely reported and for secondary outcomes results did not demonstrate differences between groups.
AUTHORS' CONCLUSIONS
It is unclear whether a combination of tocolytic drugs for preterm labour is more advantageous for women and/or newborns due to a lack of large, well-designed trials including the outcomes of interest. There are no trials of combination regimens using widely used tocolytic agents, such as calcium channel blockers (nifedipine) and/or oxytocin receptor antagonists (atosiban). Further trials are needed before specific conclusions on use of combination tocolytic therapy for preterm labour can be made.
Topics: Drug Therapy, Combination; Female; Humans; Infant, Newborn; Obstetric Labor, Premature; Pregnancy; Premature Birth; Randomized Controlled Trials as Topic; Tocolysis; Tocolytic Agents
PubMed: 25010869
DOI: 10.1002/14651858.CD006169.pub2 -
The Cochrane Database of Systematic... May 2013Magnesium maintenance therapy is one of the types of tocolytic therapy used after an episode of threatened preterm labour (usually treated with an initial dose of... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Magnesium maintenance therapy is one of the types of tocolytic therapy used after an episode of threatened preterm labour (usually treated with an initial dose of tocolytic therapy) in an attempt to prevent the onset of further preterm contractions.
OBJECTIVES
To assess whether magnesium maintenance therapy is effective in preventing preterm birth after the initial threatened preterm labour is arrested.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2013).
SELECTION CRITERIA
Randomised controlled trials of magnesium therapy given to women after threatened preterm labour.
DATA COLLECTION AND ANALYSIS
The review authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. We checked data entry.
MAIN RESULTS
We included four trials involving 422 women. Three trials had high risk of bias and none included any long-term follow-up of infants. No differences in the incidence of preterm birth or perinatal mortality were seen when magnesium maintenance therapy was compared with placebo or no treatment; or alternative therapies (ritodrine or terbutaline). The risk ratio (RR) for preterm birth (less than 37 weeks) for magnesium compared with placebo or no treatment was 1.05, 95% confidence interval (CI) 0.80 to 1.40 (two trials, 99 women); and 0.99, 95% CI 0.57 to 1.72 (two trials, 100 women) for magnesium compared with alternative therapies. The RR for perinatal mortality for magnesium compared with placebo or no treatment was 5.00, 95% CI 0.25 to 99.16 (one trial, 50 infants); and 5.00, 95% CI 0.25 to 99.16 (one trial, 50 infants) for magnesium compared with alternative treatments.Women taking magnesium preparations were less likely to report side effects (RR 0.67, 95% CI 0.47 to 0.96, three trials, 237 women), including palpitations or tachycardia (RR 0.26, 95% CI 0.13 to 0.52, three trials, 237 women) than women receiving alternative therapies. Women receiving magnesium were however, more likely to experience diarrhoea (RR 6.79, 95% CI 1.26 to 36.72, three trials, 237 women).
AUTHORS' CONCLUSIONS
There is not enough evidence to show any difference between magnesium maintenance therapy compared with either placebo or no treatment, or alternative therapies (ritodrine or terbutaline) in preventing preterm birth after an episode of threatened preterm labour.
Topics: Female; Humans; Magnesium Chloride; Magnesium Compounds; Magnesium Oxide; Magnesium Sulfate; Obstetric Labor, Premature; Pregnancy; Premature Birth; Randomized Controlled Trials as Topic; Ritodrine; Terbutaline; Tocolysis; Tocolytic Agents
PubMed: 23728634
DOI: 10.1002/14651858.CD000940.pub3 -
Singapore Medical Journal May 2006Spontaneous preterm labour and delivery accounts for approximately one-third of preterm births, which is the predominant cause of perinatal mortality and morbidity. This... (Review)
Review
Spontaneous preterm labour and delivery accounts for approximately one-third of preterm births, which is the predominant cause of perinatal mortality and morbidity. This review aims to evaluate the evidence on the benefits and harms of five classes of tocolytic therapy, namely: betamimetics, calcium channel blockers, magnesium, non-steroidal anti-inflammatory agents, and atosiban. We performed a systematic review of the effectiveness of tocolytics to stop uterine contractions (first-line therapy). Reports of randomised controlled trials from searches of MEDLINE, bibliographies of review articles, Cochrane Collaboration and its Pregnancy and Childbirth Review Group between 1966 and 2003 were identified, using the search terms "randomised controlled trial" (RCT), "preterm labor", "tocolysis", "betamimetics", "ritodrine", "prostaglandin synthetase inhibitors", "indomethacin", "calcium channel blockers", "nifedipine", "oxytocin receptor blockers", "atosiban", and "magnesium sulphate". Studies on women with preterm labour comparing the effects of a tocolytic with a placebo or no treatment that met our inclusion criteria, were included. To our knowledge, the trials were conducted mainly before 1999 and there were no placebo-controlled trials after that. Of the 86 articles identified and evaluated, 14 first-line studies met more stringent requirements for meta-analyses. Tocolytics were associated with significant decreases in the odds of delivery within 24 hours (odds-ratio [OR] 0.54, 95 percent confidence interval [CI] 0.32-0.91) and 48 hours (OR 0.47, 95 percent CI 0.30-0.75). These effects were significant for beta-agonists, atosiban and indomethacin, but not magnesium sulphate. Maternal side-effects significantly associated with betamimetics were pulmonary oedema, cardiac arrhthymias and hypokalaemia. Although calcium antagonists have not been evaluated against placebo, comparative trials with beta-agonists have shown more favourable neonatal outcomes and better prolongation of gestation. In conclusion, the management of threatened preterm labour with first-line tocolytic therapy can prolong gestation. However, the time gained in-utero need to be optimised. There is no clear first-line tocolytic agent. The use of tocolytic agents should be individualised and based on maternal condition, potential side-effects and gestational age.
Topics: Female; Humans; Obstetric Labor, Premature; Pregnancy; Pregnancy Outcome; Time Factors; Tocolysis; Tocolytic Agents
PubMed: 16645683
DOI: No ID Found -
The Cochrane Database of Systematic... Jun 2014Preterm birth, defined as birth between 20 and 36 completed weeks, is a major contributor to perinatal morbidity and mortality globally. Oxytocin receptor antagonists... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Preterm birth, defined as birth between 20 and 36 completed weeks, is a major contributor to perinatal morbidity and mortality globally. Oxytocin receptor antagonists (ORA), such as atosiban, have been specially developed for the treatment of preterm labour. ORA have been proposed as effective tocolytic agents for women in preterm labour to prolong pregnancy with fewer side effects than other tocolytic agents.
OBJECTIVES
To assess the effects on maternal, fetal and neonatal outcomes of tocolysis with ORA for women with preterm labour compared with placebo or any other tocolytic agent.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (1 December 2013).
SELECTION CRITERIA
We included all randomised controlled trials (published and unpublished) of ORA for tocolysis of labour between 20 and 36 completed weeks' gestation.
DATA COLLECTION AND ANALYSIS
Two review authors independently evaluated methodological quality and extracted trial data. When required, we sought additional data from trial authors. Results are presented as risk ratio (RR) for categorical and mean difference (MD) for continuous data with the 95% confidence intervals (CI). Where appropriate, the number needed to treat for benefit (NNTB) and the number needed to treat for harm (NNTH) were calculated.
MAIN RESULTS
This review update includes eight additional studies (790 women), giving a total of 14 studies involving 2485 women.Four studies (854 women) compared ORA (three used atosiban and one barusiban) with placebo. Three studies were considered at low risk of bias in general (blinded allocation to treatment and intervention), the fourth study did not adequately blind the intervention. No difference was shown in birth less than 48 hours after trial entry (average RR 1.05, 95% CI 0.15 to 7.43; random-effects, (two studies, 152 women), perinatal mortality (RR 2.25, 95% CI 0.79 to 6.38; two studies, 729 infants), or major neonatal morbidity. ORA (atosiban) resulted in a small reduction in birthweight (MD -138.86 g, 95% CI -250.53 to -27.18; two studies with 676 infants). In one study, atosiban resulted in an increase in extremely preterm birth (before 28 weeks' gestation) (RR 3.11, 95% CI 1.02 to 9.51; NNTH 31, 95% CI 8 to 3188) and infant deaths (up to 12 months) (RR 6.13, 95% CI 1.38 to 27.13; NNTH 28, 95% CI 6 to 377). However, this finding may be confounded due to randomisation of more women with pregnancy less than 26 weeks' gestation to atosiban. ORA also resulted in an increase in maternal adverse drug reactions requiring cessation of treatment in comparison with placebo (RR 4.02, 95% CI 2.05 to 7.85; NNTH 12, 95% CI 5 to 33). No differences were shown in preterm birth less than 37 weeks' gestation or any other adverse neonatal outcomes. No differences were evident by type of ORA, although data were limited.Eight studies (1402 women) compared ORA (atosiban only) with betamimetics; four were considered of low risk of bias (blinded allocation to treatment and to intervention). No statistically significant difference was shown in birth less than 48 hours after trial entry (RR 0.89, 95% CI 0.66 to 1.22; eight studies with 1389 women), very preterm birth (RR 1.70, 95% CI 0.89 to 3.23; one study with 145 women), extremely preterm birth (RR 0.84, 95% CI 0.37 to 1.92; one study with 244 women) or perinatal mortality (RR 0.55, 95% CI 0.21 to 1.48; three studies with 816 infants). One study (80 women), of unclear methodological quality, showed an increase in the interval between trial entry and birth (MD 22.90 days, 95% CI 18.03 to 27.77). No difference was shown in any reported measures of major neonatal morbidity (although numbers were small). ORA (atosiban) resulted in less maternal adverse effects requiring cessation of treatment (RR 0.05, 95% CI 0.02 to 0.11; NNTB 6, 95% CI 6 to 6; five studies with 1161 women).Two studies including (225 women) compared ORA (atosiban) with calcium channel blockers (CCB) (nifedipine only). The studies were considered as having high risk of bias as neither study blinded the intervention and in one study it was not known if allocation was blinded. No difference was shown in birth less than 48 hours after trial entry (average RR 1.09, 95% CI 0.44 to 2.73, random-effects; two studies, 225 women) and extremely preterm birth (RR 2.14, 95% CI 0.20 to 23.11; one study, 145 women). No data were available for the outcome of perinatal mortality. One small trial (145 women), which did not employ blinding of the intervention, showed an increase in the number of preterm births (before 37 weeks' gestation) (RR 1.56, 95% CI 1.13 to 2.14; NNTH 5, 95% CI 3 to 19), a lower gestational age at birth (MD -1.20 weeks, 95% CI -2.15 to -0.25) and an increase in admission to neonatal intensive care unit (RR 1.70, 95% CI 1.17 to 2.47; NNTH 5, 95% CI 3 to 20). ORA (atosiban) resulted in less maternal adverse effects (RR 0.38, 95% CI 0.21 to 0.68; NNTB 6, 95% CI 5 to 12; two studies, 225 women) but not maternal adverse effects requiring cessation of treatment (RR 0.36, 95% CI 0.01 to 8.62; one study, 145 women). No longer-term outcome data were included.
AUTHORS' CONCLUSIONS
This review did not demonstrate superiority of ORA (largely atosiban) as a tocolytic agent compared with placebo, betamimetics or CCB (largely nifedipine) in terms of pregnancy prolongation or neonatal outcomes, although ORA was associated with less maternal adverse effects than treatment with the CCB or betamimetics. The finding of an increase in infant deaths and more births before completion of 28 weeks of gestation in one placebo-controlled study warrants caution. However, the number of women enrolled at very low gestations was small. Due to limitations of small numbers studied and methodological quality, further well-designed randomised controlled trials are needed. Further comparisons of ORA versus CCB (which has a better side-effect profile than betamimetics) are needed. Consideration of further placebo-controlled studies seems warranted. Future studies of tocolytic agents should measure all important short- and long-term outcomes for women and infants, and costs.
Topics: Albuterol; Female; Humans; Infant, Extremely Low Birth Weight; Infant, Newborn; Obstetric Labor, Premature; Oligopeptides; Pregnancy; Randomized Controlled Trials as Topic; Receptors, Oxytocin; Ritodrine; Terbutaline; Tocolytic Agents; Vasotocin
PubMed: 24903678
DOI: 10.1002/14651858.CD004452.pub3 -
The Cochrane Database of Systematic... 2000Betamimetic drugs may promote fetal growth by increasing the availability of nutrients and by decreasing vascular resistance. They may also induce adverse effects via... (Review)
Review
BACKGROUND
Betamimetic drugs may promote fetal growth by increasing the availability of nutrients and by decreasing vascular resistance. They may also induce adverse effects via their effects on carbohydrate metabolism.
OBJECTIVES
The objective of this review was to assess the effects of betamimetic therapy for suspected impaired fetal growth on fetal growth and perinatal outcome.
SEARCH STRATEGY
We searched the Cochrane Pregnancy and Childbirth Group trials register and the Cochrane Controlled Trials Register. Date of the latest search: December 1999.
SELECTION CRITERIA
Randomised trials of betamimetic therapy compared with no betamimetic therapy or placebo in women with suspected impaired fetal growth.
DATA COLLECTION AND ANALYSIS
Eligibility and trial quality was assessed.
MAIN RESULTS
Two studies of 118 women were included. No differences were found between the betamimetic groups and the control groups for low birth weight (relative risk 1.17, 95% confidence interval 0.75 to 1.83), other anthropometric or neonatal morbidity and mortality measures.
REVIEWER'S CONCLUSIONS
There is not enough evidence to evaluate the use of betamimetics in promoting fetal growth. Larger studies are needed to investigate possible adverse effects of long-term betamimetic administration.
Topics: Adrenergic beta-Agonists; Female; Fetal Growth Retardation; Humans; Pregnancy; Ritodrine; Tocolytic Agents
PubMed: 10796095
DOI: 10.1002/14651858.CD000036 -
The Cochrane Database of Systematic... Dec 2015Twin pregnancies are associated with a high risk of neonatal mortality and morbidity due to an increased rate of preterm birth. Betamimetics can decrease contraction... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Twin pregnancies are associated with a high risk of neonatal mortality and morbidity due to an increased rate of preterm birth. Betamimetics can decrease contraction frequency or delay preterm birth in singleton pregnancies by 24 to 48 hours. The efficacy of oral betamimetics in women with a twin pregnancy is unproven.
OBJECTIVES
To assess the effectiveness of prophylactic oral betamimetics for the prevention of preterm labour and birth for women with twin pregnancies.
SEARCH METHODS
We searched the Cochrane Pregnancy and Childbirth Group Trials Register (21 September 2015), MEDLINE (January 1966 to 31 July 2015), EMBASE (January 1985 to 31 July 2015) and reference lists of retrieved studies.
SELECTION CRITERIA
Randomised controlled trials in twin pregnancies comparing oral betamimetics with placebo or any intervention with the specific aim of preventing preterm birth. Quasi-randomised controlled trials, cluster-randomised trials and cross-over trials were not eligible for inclusion.
DATA COLLECTION AND ANALYSIS
Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Two authors assessed the quality of the evidence using the GRADE approach.
MAIN RESULTS
Overall, the quality of evidence is low for the primary outcomes. All of the included trials had small numbers of participants and few events. Preterm birth, the most important primary outcome, had wide confidence intervals crossing the line of no effect.Six trials (374 twin pregnancies) were included, but only five trials (344 twin pregnancies) contributed data. All trials compared oral betamimetics with placebo.Betamimetics reduced the incidence of preterm labour (two trials, 194 twin pregnancies, risk ratio (RR) 0.37; 95% confidence interval (CI) 0.17 to 0.78; low quality evidence). However, betamimetics did not reduce prelabour rupture of membranes (one trial, 144 twin pregnancies, RR 1.42; 95% CI 0.42 to 4.82; low quality evidence), preterm birth less than 37 weeks' gestation (four trials, 276 twin pregnancies, RR 0.85; 95% CI 0.65 to 1.10; low quality evidence), or less than 34 weeks' gestation (one trial, 144 twin pregnancies, RR 0.47; 95% CI 0.15 to 1.50; low quality evidence). Mean neonatal birthweight in the betamimetic group was significantly higher than in the placebo group (three trials, 478 neonates, mean difference 111.22 g; 95% CI 22.21 to 200.24). Nevertheless, there was no evidence of an effect of betamimetics in reduction of low birthweight (two trials, 366 neonates, average RR 1.19; 95% CI 0.77 to 1.85, random-effects), or small-for-gestational age neonates (two trials, 178 neonates, average RR 0.90; 95% CI 0.41 to 1.99, random-effects). Two trials showed that betamimetics significantly reduced the incidence of respiratory distress syndrome (388 neonates, RR 0.30; 95% CI 0.12 to 0.77), but the difference was not significant when the analysis was adjusted to account for the non-independence of twins (194 twins, RR 0.35; 95% CI 0.11 to 1.16). Three trials showed no evidence of an effect of betamimetics in reducing neonatal mortality, either with the unadjusted analysis, assuming twins are completely independent of each other (452 neonates, average RR 0.90; 95% CI 0.15 to 5.37, random-effects), or in the adjusted analysis, assuming non-independence of twins (226 twins, average RR 0.74; 95% CI 0.23 to 2.38, random-effects). A maternal death was reported in one trial without a significant difference between the groups (144 women, RR 2.84; 95% CI 0.12 to 68.57).
AUTHORS' CONCLUSIONS
There is insufficient evidence to support or refute the use of prophylactic oral betamimetics for preventing preterm birth in women with a twin pregnancy.
Topics: Administration, Oral; Adrenergic beta-Agonists; Adult; Albuterol; Female; Fenoterol; Fetal Membranes, Premature Rupture; Gestational Age; Humans; Isoxsuprine; Pregnancy; Pregnancy, Twin; Premature Birth; Randomized Controlled Trials as Topic; Ritodrine; Terbutaline; Tocolytic Agents
PubMed: 26645888
DOI: 10.1002/14651858.CD004733.pub4