Four kinds of tocolytic therapy for preterm delivery: Systematic review and network meta-analysis.

WHAT IS KNOWN AND OBJECTIVE: Premature birth affects more than 15 million infants, as well as mothers and families around the world. With the relaxation of the two-child policy, the problem of premature birth has become relatively prominent in China. According to statistics, China had a birth population of 15.23 million in 2018, with a considerably large number of premature births. This study aims to evaluate the efficacy and safety of tocolysis in the treatment of preterm delivery, provide clinical evidence for medical staff and promote the self-management of patients with premature births. METHODS: Four English databases (PubMed, Embase, Cochrane Library and Web of Science) were retrieved by computer, the retrieval time was from the establishment of each database to November 2021, and the randomized controlled trials for the treatment of preterm delivery were screened according to the pre-set natriuretic exclusion criteria. After literature screening, data selection and risk of bias evaluation were independently conducted by two researchers. R 4.1.1 and Stata 17.0 software were used for statistical analysis. RESULTS AND DISCUSSION: A total of 44 RCTs were included, including 6939 patients. The results of network meta-analysis reveal that in terms of effectiveness, indomethacin was the most effective intervention measure, followed by nifedipine, and the difference was statistically significant; regarding safety, nifedipine was the safest intervention measure, followed by indomethacin, and the difference was statistically significant; and in respect of adverse reactions, ritodrine had the highest probability, and the difference was statistically significant. WHAT IS NEW AND CONCLUSION: Nifedipine may be better for delayed delivery and less likely to produce adverse pregnancy outcomes, followed by indomethacin. Limited by the number and quality of recipient studies, the aforementioned conclusions need to be verified through more high-quality studies. At the same time, the focus should be on patients with twin pregnancy and patients with clinical manifestations of extreme preterm delivery.

Tocolysis in the management of preterm prelabor rupture of membranes at 22-33 weeks of gestation: study protocol for a multicenter, double-blind, randomized controlled trial comparing nifedipine with placebo (TOCOPROM).

BACKGROUND: Preterm prelabor rupture of membranes (PPROM) before 34 weeks of gestation complicates 1% of pregnancies and accounts for one-third of preterm births. International guidelines recommend expectant management, along with antenatal steroids before 34 weeks and antibiotics. Up-to-date evidence about the risks and benefits of administering tocolysis after PPROM, however, is lacking. In theory, reducing uterine contractility could delay delivery and reduce the risks of prematurity and its adverse short- and long-term consequences, but it might also prolong fetal exposure to inflammation, infection, and acute obstetric complications, potentially associated with neonatal death or long-term sequelae. The primary objective of this study is to assess whether short-term (48 h) tocolysis reduces perinatal mortality/morbidity in PPROM at 22 to 33 completed weeks of gestation. METHODS: A randomized, double-blind, placebo-controlled, superiority trial will be performed in 29 French maternity units. Women with PPROM between 220/7 and 336/7 weeks of gestation, a singleton pregnancy, and no condition contraindicating expectant management will be randomized to receive a 48-hour oral treatment by either nifedipine or placebo (1:1 ratio). The primary outcome will be the occurrence of perinatal mortality/morbidity, a composite outcome including fetal death, neonatal death, or severe neonatal morbidity before discharge. If we assume an alpha-risk of 0.05 and beta-risk of 0.20 (i.e., a statistical power of 80%), 702 women (351 per arm) are required to show a reduction of the primary endpoint from 35% (placebo group) to 25% (nifedipine group). We plan to increase the required number of subjects by 20%, to replace any patients who leave the study early. The total number of subjects required is thus 850. Data will be analyzed by the intention-to-treat principle. DISCUSSION: This trial will inform practices and policies worldwide. Optimized prenatal management to improve the prognosis of infants born preterm could benefit about 50,000 women in the European Union and 40,000 in the United States each year. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT03976063 (registration date June 5, 2019).

The effectiveness of nifedipine/indomethacin combination therapy and nifedipine monotherapy for postponing preterm birth (25-34 weeks of gestation) in Sudanese women: a randomized clinical trial study protocol.

BACKGROUND: Preterm birth is the most common cause of neonatal morbidity and mortality. Tocolytics are considered a standard treatment for women with threatened preterm delivery to allow time for maternal steroid administration and transfer to referral centers with neonatal intensive care units. However, there is controversy about the best tocolytic therapy to be considered as the first choice. The aim of this study is to compare the tocolytic effectiveness and tolerability of combination therapy with nifedipine and indomethacin versus nifedipine monotherapy among Sudanese women with preterm labor (PTL) as well as to compare the possible neonatal outcomes associated with each drug. METHODS/DESIGN: This is a randomized controlled clinical trial to be conducted in the Medani Maternity Hospital, Sudan. Women aged 18-40 years that are diagnosed with preterm labor and have a gestational age between 25 and 34 weeks will be eligible to participate in this trial. The diagnosis of threatened PTL is defined as persistent uterine contractions "(four contractions every 20 min or eight contractions every 60 min)" with cervical changes "(cervical effacement ≤80% or cervical dilatation >two cm)". Patients will be eligible regardless of the presentation of the fetus. It will be randomly decided whether participants receive nifedipine/indomethacin combination therapy or nifedipine monotherapy. The primary outcome is the number of women who do not deliver and do not need alternative tocolytic drug (terbutaline). The secondary outcome is an estimated association with neonatal morbidity and mortality. The sample size will be 117 subjects in each arm of the study, according to a type I error of 0.05 and a study power of 80%. DISCUSSION: We expect higher effectiveness of the combination indomethacin/nifedipine tocolytic therapy compared with nifedipine monotherapy. We plan to suggest this combination therapy as the best option for postponing PTL. TRIAL REGISTRATION: Clinical trial registration: PACTR202004681537890 , date of registration: March 8, 2020.

A comparative study of transdermal nitroglycerine patch and oral nifedipine in preterm labor.

Background: Currently, the main goal for the use of tocolytic therapy is to delay the birth so as to allow the use of corticosteroids for accelerating fetal lung maturity and maternal transfer to a tertiary care center and thereby reducing neonatal morbidity and mortality. Aims and Objectives: The aims amd objectives were to compare the safety and efficacy of transdermal nitroglycerine patch with oral nifedipine as a tocolytic agent to arrest preterm labor and prevent preterm birth. Materials and Methods: Based on the selection criteria, 50 patients were selected randomly in Group A and Group B. Group A women were given transdermal nitroglycerin patch, which delivered 10 mg Nitroglycerin (NTG) over 24 h and it was applied to the woman's abdomen followed by another patch of 10 mg after 1 h if contractions persisted. After 24 h, it was replaced by a fresh patch. Group B women were given an oral loading dose of nifedipine 20 mg followed by a similar dose if contractions persisted after 1 h. A maintenance dose of 10 mg thrice daily was given if contractions were suppressed. Patients were monitored from the time of admission to the time of discharge. Results: The mean duration of prolongation of pregnancy in Group B (3.68 ± 1.91 days) was significantly more than Group A (2.78 ± 1.39 days). Headache was seen significantly more in Group A (42%) than group B (6%). Tachycardia, hypotension, and palpitation showed no statistically significant difference between them. There was no statistically significant difference in the birth weight of the babies in both the groups. Conclusion: Nifedipine is a safe and effective drug in prolonging preterm labor and has minimal maternal and neonatal side effects.

RésuméContexte: Actuellement, le principal objectif de l'utilisation de la thérapie tocolytique est de retarder la naissance afin de permettre l'utilisation de corticostéroïdes pour accélérer la maturité pulmonaire fœtale et le transfert maternel vers un centre de soins tertiaires et ainsi réduire la morbidité et la mortalité néonatales. Buts et objectifs: Les buts et objectifs étaient de comparer l'innocuité et l'efficacité du timbre transdermique de nitroglycérine avec la nifédipine par voie orale comme agent tocolytique pour arrêter le travail prématuré et prévenir l'accouchement prématuré. Matériel et méthodes: Sur la base des critères de sélection, 50 patientes ont été sélectionnées au hasard dans les groupes A et B.Les femmes du groupe A ont reçu un patch transdermique de nitroglycérine, qui a administré 10 mg de NTG en 24 h et appliqué sur l'abdomen de la femme suivi d'un autre patch de 10 mg après 1 h si les contractions ont persisté. Après 24 h, il a été remplacé par un nouveau patch. Les femmes du groupe B ont reçu une dose de charge orale de 20 mg de nifédipine suivie d'une dose similaire si les contractions persistaient après 1 h. Une dose d'entretien de 10 mg trois fois par jour était administrée si les contractions étaient supprimées. Les patients ont été suivis du moment de l'admission au moment de la sortie. Résultats: La durée moyenne de prolongation de la grossesse dans le groupe B (3,68 ± 1,91 jours) était significativement plus élevée que dans le groupe A (2,78 ± 1,39 jours). Les céphalées étaient significativement plus observées dans le groupe A (42%) que dans le groupe B (6%). La tachycardie, l'hypotension et les palpitations n'ont montré aucune différence statistiquement significative entre elles. Il n'y avait pas de différence statistiquement significative du poids à la naissance des bébés dans les deux groupes. Conclusion: La nifédipine est un médicament sûr et efficace pour prolonger le travail prématuré et a des effets secondaires maternels et néonatals minimes.

Nifedipine versus placebo in the treatment of preterm prelabor rupture of membranes: a randomized controlled trial: Assessment of perinatal outcome by use of tocolysis in early labor-APOSTEL IV trial.

OBJECTIVE: Preterm birth is the most common cause of neonatal morbidity and mortality. Around one third of preterm deliveries starts with preterm prelabor rupture of membranes (PPROM). The aim of this trial was to study the effect of prolonged tocolysis with nifedipine versus placebo in women with PPROM on perinatal outcome and prolongation of pregnancy. STUDY DESIGN: The Apostel IV was a nationwide multicenter randomized placebo controlled trial. We included women with PPROM without contractions between 24(+0) and 33(+6) weeks of gestation. Participants were randomly allocated to daily 80mg nifedipine or placebo, until the start of labor, with a maximum of 18 days. The primary outcome measure was a composite of poor neonatal outcome, including perinatal death, bronchopulmonary dysplasia, periventricular leukomalacia>grade 1, intraventricular hemorrhage>grade 2, necrotizing enterocolitis>stage 1 and culture proven sepsis. Secondary outcomes were gestational age at delivery and prolongation of pregnancy. Analysis was by intention to treat. To detect a reduction of poor neonatal outcome from 30% to 10%, 120 women needed to be randomized. TRIAL REGISTRY: NTR 3363. RESULTS: Between October 2012 and December 2014 we randomized 25 women to nifedipine and 25 women to placebo. Due to slow recruitment the study was stopped prematurely. The median gestational age at randomization was 29.9 weeks (IQR 27.7-31.3) in the nifedipine group and 27.0 weeks (IQR 24.7-29.9) in the placebo group. Other baseline characteristics were comparable. The adverse perinatal outcome occurred in 9 neonates (33.3%) in the nifedipine group and 9 neonates (32.1%) in the placebo group (RR 1.04, 95% CI 0.49-2.2). Two perinatal deaths occurred, both in the nifedipine group. Bronchopulmonary dysplasia was seen less frequently in the nifedipine group (0% versus 17.9%; p=0.03). Prolongation of pregnancy did not differ between the nifedipine and placebo group (median 11 versus 8 days, HR 1.02; 95% CI 0.58-1.79). CONCLUSION: This randomized trial did not show a beneficial effect of prolonged tocolysis on neonatal outcomes or prolongation of pregnancy in women with PPROM without contractions. However, since results are based on a small sample size, a difference in effectiveness cannot be excluded.

Nifedipine maintenance tocolysis and perinatal outcome: an individual participant data meta-analysis.

BACKGROUND: Preterm birth is the leading cause of neonatal mortality and morbidity in developed countries. Whether continued tocolysis after 48 hours of rescue tocolysis improves neonatal outcome is unproven. OBJECTIVES: To evaluate the effectiveness of maintenance tocolytic therapy with oral nifedipine on the reduction of adverse neonatal outcomes and the prolongation of pregnancy by performing an individual patient data meta-analysis (IPDMA). SEARCH STRATEGY: We searched PubMed, Embase, and Cochrane databases for randomised controlled trials of maintenance tocolysis therapy with nifedipine in preterm labour. SELECTION CRITERIA: We selected trials including pregnant women between 24 and 36(6/7)  weeks of gestation (gestational age, GA) with imminent preterm labour who had not delivered after 48 hours of initial tocolysis, and compared maintenance nifedipine tocolysis with placebo/no treatment. DATA COLLECTION AND ANALYSIS: The primary outcome was perinatal mortality. Secondary outcome measures were intraventricular haemorrhage (IVH), necrotising enterocolitis (NEC), infant respiratory distress syndrome (IRDS), prolongation of pregnancy, GA at delivery, birthweight, neonatal intensive care unit admission, and number of days on ventilation support. Pre-specified subgroup analyses were performed. MAIN RESULTS: Six randomised controlled trials were included in this IPDMA, encompassing data from 787 patients (n = 390 for nifedipine; n = 397 for placebo/no treatment). There was no difference between the groups for the incidence of perinatal death (risk ratio, RR 1.36; 95% confidence interval, 95% CI 0.35-5.33), intraventricular haemorrhage (IVH) ≥ grade II (RR 0.65; 95% CI 0.16-2.67), necrotising enterocolitis (NEC) (RR 1.15; 95% CI 0.50-2.65), infant respiratory distress syndrome (IRDS) (RR 0.98; 95% CI 0.51-1.85), and prolongation of pregnancy (hazard ratio, HR 0.74; 95% CI 0.55-1.01). CONCLUSION: Maintenance tocolysis is not associated with improved perinatal outcome and is therefore not recommended for routine practice. TWEETABLE ABSTRACT: Nifedipine maintenance tocolysis is not associated with improved perinatal outcome or pregnancy prolongation.

Progesterone and nifedipine for maintenance tocolysis after arrested preterm labor: A systematic review and meta-analysis of randomized controlled trial.

OBJECTIVE: No treatment is recommended for routine maintenance tocolysis after an arrested preterm birth. Our present study aimed to evaluate the effect of progesterone and nifedipine as maintenance tocolysis therapy after an arrested preterm birth. MATERIALS AND METHODS: For relevant studies, we systematically searched the literature in databases of PubMed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library. Only randomized controlled trials were included. RESULTS: Nine trials were included in our review. Nifedipine and progesterone were used for maintenance tocolysis. Compared to placebo treatment or no treatment, maintenance tocolysis with progesterone could significantly prolong the delivery gestational weeks [standard mean difference (SMD) 1.64; 95% confidence interval (CI), 1.21, 2.07; p < 0.00001], reduce the proportion of patients with delivery before 37 weeks (risk ratio 0.63; 95% CI, 0.47, 0.83; p = 0.001), and increase the birth weight (SMD 317.71; 95% CI, 174.89, 460.53; p < 0.0001). However, no such benefits were observed after maintenance tocolysis with nifedipine. Both nifedipine and progesterone had no significant influences on the following outcomes: neonatal intensive care unit stay, proportion of neonatal intensive care unit admission, neonatal mortality, and incidence of respiratory distress syndrome. CONCLUSION: Our results with maintenance tocolysis with progesterone may be useful for patients who had an episode of threatened preterm labor successfully treated with acute tocolytic therapy.

Alternativas terapéuticas para la tocólisis en el manejo de la amenaza de parto pretérmino / Therapeutic alternatives for the tocolysis in the management of the threatened preterm labour

La amenaza de parto pretérmino (APP) es una urgencia obstétrica que, en ausencia de intervención, desemboca en un parto prematuro. Detener la APP y prolongar la gestación todo lo posible permite trasladar a la gestante a un centro apropiado, administrar los cuidados necesarios y conceder un mayor periodo de maduración al feto, esencial para reducir la morbimortalidad asociada al parto prematuro. El empleo de tocolíticos al inicio de este proceso es esencial. En este artículo se revisa el escenario clínico y la información sobre los tocolíticos actualmente autorizados en España, dos de ellos por vía intravenosa (ritodrina y atosibán) y otro por vía oral (nifedipino solución oral) (AU)

Threatened preterm labour is an urgent obstetric condition leading to a preterm birth in the absence of medical intervention. Intervention must focus on stopping birth progression in order for the patient and the fetus be administered an adequate medical care, providing a temporal window for fetus´ maturation. This medical management is aimed to reduce the morbimortality associated to preterm birth. This manuscript consists of a review of the toclytics of more extended use in our context. Currently, three drugs are authorised as tocolytics in Spain: ritodrine and atosiban (intravenous) and nifedipine (oral solution) (AU)

Maintenance tocolysis with nifedipine in threatened preterm labour: 2-year follow up of the offspring in the APOSTEL II trial.

OBJECTIVE: To evaluate long-term effects of maintenance tocolysis with nifedipine on neurodevelopmental outcome of the infant. DESIGN, SETTING AND POPULATION: Follow up of infants of women who participated in a multicentre randomised controlled trial on maintenance tocolysis with nifedipine versus placebo. METHODS: Two years after the APOSTEL II trial on maintenance tocolysis with nifedipine versus placebo, we asked participants to complete the Ages and Stages Questionnaire. MAIN OUTCOME MEASURES: Infant development was measured in five domains. Developmental delay was defined as a score of ≤1 SD in one or more developmental domains. We performed exploratory subgroup analysis in women with preterm prolonged rupture of the membranes, and in women with a cervical length <10 mm at study entry. RESULTS: Of the 276 women eligible for follow up, 135 (52.5%) returned the questionnaire, encompassing data of 170 infants. At 2 years of age, infants of women with nifedipine maintenance tocolysis compared with placebo had a higher overall incidence of fine motor problems (22.2 versus 7.6%, OR 3.43, 95% CI 1.29-9.14, P = 0.01), and a lower incidence of poor problem-solving (21.1 versus 29.1%, OR 0.27, 95% CI 0.08-0.95, P = 0.04). CONCLUSIONS: This follow-up study revealed no clear benefit of nifedipine maintenance tocolysis at 2 years of age. As short-term adverse perinatal outcome was not reduced in the original APOSTEL II trial, we conclude that maintenance tocolysis does not appear to be beneficial at this time. TWEETABLE ABSTRACT: No clear benefit of nifedipine maintenance tocolysis in preterm labour on 2-year infant outcome.

Different treatment regimens of magnesium sulphate for tocolysis in women in preterm labour.

BACKGROUND: Magnesium sulphate has been used to inhibit preterm labour to prevent preterm birth. There is no consensus as to the safety profile of different treatment regimens with respect to dose, duration, route and timing of administration. OBJECTIVES: To assess the efficacy and safety of alternative magnesium sulphate regimens when used as single agent tocolytic therapy during pregnancy. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2015) and reference lists of retrieved studies. SELECTION CRITERIA: Randomised trials comparing different magnesium sulphate treatment regimens when used as single agent tocolytic therapy during pregnancy in women in preterm labour. Quasi-randomised trials were eligible for inclusion but none were identified. Cross-over and cluster trials were not eligible for inclusion. Health outcomes were considered at the level of the mother, the infant/child and the health service. INTERVENTION: intravenous or oral magnesium sulphate given alone for tocolysis.Comparison: alternative dosing regimens of magnesium sulphate given alone for tocolysis. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial eligibility and quality and extracted data. MAIN RESULTS: Three trials including 360 women and their infants were identified as eligible for inclusion in this review. Two trials were rated as low risk of bias for random sequence generation and concealment of allocation. A third trial was assessed as unclear risk of bias for these domains but did not report data for any of the outcomes examined in this review. No trials were rated to be of high quality overall.Intravenous magnesium sulphate was administered according to low-dose regimens (4 g loading dose followed by 2 g/hour continuous infusion and/or increased by 1 g/hour hourly until successful tocolysis or failure of treatment), or high-dose regimens (4 g loading dose followed by 5 g/hour continuous infusion and increased by 1 g/hour hourly until successful tocolysis or failure of treatment, or 6 g loading dose followed by 2 g/hour continuous infusion and increased by 1 g/hour hourly until successful tocolysis or failure of treatment).There were no differences seen between high-dose magnesium sulphate regimens compared with low-dose magnesium sulphate regimens for the primary outcome of fetal, neonatal and infant death (risk ratio (RR) 0.43, 95% confidence interval (CI) 0.12 to 1.56; one trial, 100 infants). Using the GRADE approach, the evidence for fetal, neonatal and infant death was considered to be VERY LOW quality. No data were reported for any of the other primary maternal and infant health outcomes (birth less than 48 hours after trial entry; composite serious infant outcome; composite serious maternal outcome).There were no clear differences seen between high-dose magnesium sulphate regimens compared with low-dose magnesium sulphate regimens for the secondary infant health outcomes of fetal death; neonatal death; and rate of hypocalcaemia, osteopenia or fracture; and secondary maternal health outcomes of rate of caesarean birth; pulmonary oedema; and maternal self-reported adverse effects. Pulmonary oedema was reported in two women given high-dose magnesium sulphate, but not in any of the women given low-dose magnesium sulphate.In a single trial of high and low doses of magnesium sulphate for tocolysis including 100 infants, the risk of respiratory distress syndrome was lower with use of a high-dose regimen compared with a low-dose regimen (RR 0.31, 95% CI 0.11 to 0.88; one trial, 100 infants). Using the GRADE approach, the evidence for respiratory distress syndrome was judged to be LOW quality. No difference was seen in the rate of admission to the neonatal intensive care unit. However, for those babies admitted, a high-dose regimen was associated with a reduction in the length of stay in the neonatal intensive care unit compared with a low-dose regimen (mean difference -3.10 days, 95% confidence interval -5.48 to -0.72).We found no data for the majority of our secondary outcomes. AUTHORS' CONCLUSIONS: There are limited data available (three studies, with data from only two studies) comparing different dosing regimens of magnesium sulphate given as single agent tocolytic therapy for the prevention of preterm birth. There is no evidence examining duration of therapy, timing of therapy and the role for repeat dosing.Downgrading decisions for our primary outcome of fetal, neonatal and infant death were based on wide confidence intervals (crossing the line of no effect), lack of blinding and a limited number of studies. No data were available for any of our other important outcomes: birth less than 48 hours after trial entry; composite serious infant outcome; composite serious maternal outcome. The data are limited by volume and the outcomes reported. Only eight of our 45 pre-specified primary and secondary maternal and infant health outcomes were reported on in the included studies. No long-term outcomes were reported. Downgrading decisions for the evidence on the risk of respiratory distress were based on wide confidence intervals (crossing the line of no effect) and lack of blinding.There is some evidence from a single study suggesting a reduction in the length of stay in the neonatal intensive care unit and a reduced risk of respiratory distress syndrome where a high-dose regimen of magnesium sulphate has been used compared with a low-dose regimen. However, given that evidence has been drawn from a single study (with a small sample size), these data should be interpreted with caution.Magnesium sulphate has been shown to be of benefit in a wide range of obstetric settings, although it has not been recommended for tocolysis. In clinical settings where health benefits are established, further trials are needed to address the lack of evidence regarding the optimal dose (loading dose and maintenance dose), duration of therapy, timing of therapy and role for repeat dosing in terms of efficacy and safety for mothers and their children. Ongoing examination of different regimens with respect to important health outcomes is required.

Single versus combination tocolytic regimen in the prevention of preterm births in women: a prospective cohort study.

OBJECTIVE: Our objective is to compare the efficacy of combination regimen (salbutamol and nifedipine) against single regimen (nifedipine alone) in preventing preterm births among women with preterm labor. RESULTS: A total of 76 women with gestational age (GA) ranging from 24+0 to 35+6 weeks, who sought treatment for preterm labor with or without cervical dilatation, were recruited for the prospective cohort study. Of these, 38 (50%) had single tocolytic regimen and 38 (50%) had combination tocolytic regimen. The mean GAs at admission were similar for both groups at 31 weeks (±2.93) for Group 1 and 30.9 weeks (±2.88) for Group 2 (P=0.873). The mean GAs at delivery were 37.8 weeks (±1.98) for the single regimen and 36.2 weeks (±3.26) for the combined regimen (P=0.011). The mean tocolytic to delivery interval for the single regimen was longer at 6.74 weeks (±3.13) as compared with 5.21 weeks (±3.61) for the combination regimen (P<0.05). Those on the combination regimen complained of more adverse effects (P<0.001). CONCLUSION: Our study results suggested that the use of nifedipine as a single tocolytic regimen is as effective as the combination regimen in the delay of preterm births and has much less side effects. Hence, we recommend the sole use of nifedipine for the management of preterm labor.

Estudio observacional de la efectividad y seguridad de nifedipino en la amenaza de parto prematuro / Observational study of the safety and effectiveness of nifedipine in pre-term labor

Objetivos. Analizar la efectividad y seguridad del nifedipino en gestantes con amenaza de parto prematuro (APP). Sujetos y métodos. Estudio observacional prospectivo de abril de 2003 a diciembre de 2004 y retrospectivo de enero a diciembre de 2008. Se incluyeron 106 gestantes a las que se aplicó el protocolo de APP del hospital. Se excluyeron 33 por diferentes motivos, principalmente falsos diagnósticos de APP. Resultados. La prolongación del parto fue superior a 48 h en el 56,2% (IC 95%: 44,8-67,5) y se administraron 2 dosis de betametasona en el 69,9% (IC 95%: 59,3-80,4). La incidencia de reacciones adversas maternas fue del 29,4% (IC 95%:7,8-51,2), principalmente hipotensión leve. De los 99 recién nacidos hubo 10 fallecimientos, principalmente por complicaciones infecciosas y bajo peso, y hubo un caso de encefalopatía hipóxico-isquémica. Conclusiones. La tocólisis con nifedipino es efectiva y segura si se respetan las precauciones de uso de forma estricta, registrando una baja incidencia de efectos adversos maternos y fetales (AU)

Objectives. To determine the effectiveness and safety of nifedipine as a tocolytic agent in pregnant women with preterm labor (PL). Subjects and methods. We performed a prospective observational study (April 2003 - December 2004) and a retrospective study (January- December 2008). A total of 106 pregnant women were included and the hospital PL protocol was applied. Thirty-three patients were excluded for different reasons, mainly because of a false PL diagnosis. Results. Pregnancy was prolonged by more than 48 hours in 56.2% [95% CI: 44.8-67.5] and 2 doses of betametasone were administered in 69.9% [95% CI: 59.3-80.4]. The incidence of maternal adverse reactions was 29.4% (95% CI: 7.8-51.2), mainly mild hypotension. Of the 99 newborns, 10 died, mainly because of infectious complications and low birthweight and there was one case of hypoxic-ischemic encephalopathy. Conclusions. Tocolysis with nifedipine is safe and effective if precautions for use are strictly respected. In this study, there was a low incidence of maternal and fetal adverse effects (AU)

Tocolytics for preterm premature rupture of membranes.

BACKGROUND: In women with preterm labor, tocolysis has not been shown to improve perinatal mortality; however, it is often given for 48 hours to allow for the corticosteroid effect for fetal maturation. In women with preterm premature rupture of membranes (PPROM), the use of tocolysis is still controversial. In theory, tocolysis may prolong pregnancy in women with PPROM, thereby allowing for the corticosteroid benefit and reducing the morbidity and mortality associated with prematurity. OBJECTIVES: To assess the potential benefits and harms of tocolysis in women with preterm premature rupture of membranes. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (15 January 2014). SELECTION CRITERIA: We included pregnant women with singleton pregnancies and PPROM (23 weeks to 36 weeks and six days). We included any tocolytic therapy compared to no tocolytic, placebo, or another tocolytic. DATA COLLECTION AND ANALYSIS: All review authors assessed the studies for inclusion. We extracted and quality assessed data. MAIN RESULTS: We included eight studies with a total of 408 women. Seven of the studies compared tocolysis to no tocolysis. One study compared nifedipine to terbutaline. Compared to no tocolysis, tocolysis was not associated with a significant effect on perinatal mortality in women with PPROM (risk ratio (RR) 1.67; 95% confidence interval (CI) 0.85 to 3.29). Tocolysis was associated with longer latency (mean difference (MD) 73.12 hours; 95% CI 20.21 to 126.03; three trials of 198 women) and fewer births within 48 hours (average RR 0.55; 95% CI 0.32 to 0.95; six trials of 354 women; random-effects, Tau² = 0.18, I² = 43%) compared to no tocolysis. However, tocolysis was associated with increased five-minute Apgar of less than seven (RR 6.05; 95% CI 1.65 to 22.23; two trials of 160 women) and increased need for ventilation of the neonate (RR 2.46; 95% CI 1.14 to 5.34; one trial of 81 women). In the subgroup analysis comparing betamimetic to no betamimetics, tocolysis was associated with increased latency and borderline significance for chorioamnionitis. Prophylactic tocolysis with PPROM was associated with increased overall latency, without additional benefits for maternal/neonatal outcomes. For women with PPROM before 34 weeks, there was a significantly increased risk of chorioamnionitis in women who received tocolysis. However, neonatal outcomes were not significantly different. There were no significant differences in maternal/neonatal outcomes in subgroup analyses comparing cox inhibitor versus no tocolysis, calcium channel blocker versus betamimetic, antibiotic, corticosteroid or combined antibiotic/corticosteroid. AUTHORS' CONCLUSIONS: Our review suggests there is insufficient evidence to support tocolytic therapy for women with PPROM, as there was an increase in maternal chorioamnionitis without significant benefits to the infant. However, studies did not consistently administer latency antibiotics and corticosteroids, both of which are now considered standard of care.

Nifedipine versus atosiban in the treatment of threatened preterm labour (Assessment of Perinatal Outcome after Specific Tocolysis in Early Labour: APOSTEL III-Trial).

BACKGROUND: Preterm birth is the most common cause of neonatal morbidity and mortality. Postponing delivery for 48 hours with tocolytics to allow for maternal steroid administration and antenatal transportation to a centre with neonatal intensive care unit facilities is the standard treatment for women with threatening preterm delivery in most centres. However, there is controversy as to which tocolytic agent is the drug of first choice. Previous trials have focused on tocolytic efficacy and side effects, and are probably underpowered to detect clinically meaningfull differences in neonatal outcome. Thus, the current evidence is inconclusive to support a balanced recommendation for clinical practice. This multicenter randomised clinical trial aims to compare nifedipine and atosiban in terms of neonatal outcome, duration of pregnancy and maternal side effects. METHODS/DESIGN: The Apostel III trial is a nationwide multicenter randomised controlled study. Women with threatened preterm labour (gestational age 25 - 34 weeks) defined as at least 3 contractions per 30 minutes, and 1) a cervical length of ≤ 10 mm or 2) a cervical length of 11-30 mm and a positive Fibronectin test or 3) ruptured membranes will be randomly allocated to treatment with nifedipine or atosiban. Primary outcome is a composite measure of severe neonatal morbidity and mortality. Secondary outcomes will be time to delivery, gestational age at delivery, days on ventilation support, neonatal intensive care (NICU) admittance, length admission in neonatal intensive care, total days in hospital until 3 months corrected age, convulsions, apnoea, asphyxia, proven meningitis, pneumothorax, maternal side effects and costs. Furthermore, an economic evaluation of the treatment will be performed. Analysis will be by intention to treat principle. The power calculation is based on an expected 10% difference in the prevalence of adverse neonatal outcome. This implies that 500 women have to be randomised (two sided test, ß 0.2 at alpha 0.05). DISCUSSION: This trial will provide evidence on the optimal drug of choice in acute tocolysis in threatening preterm labour. CLINICAL TRIAL REGISTRATION: NTR2947, date of registration: June 20th 2011.

Maintenance therapy with calcium channel blockers for preventing preterm birth after threatened preterm labour.

BACKGROUND: Calcium channel blocker maintenance therapy is one of the types of tocolytic therapy that may be used after an episode of threatened preterm labour (and usually an initial dose of tocolytic therapy) in an attempt to prevent the onset of further preterm contractions. OBJECTIVES: To assess the effects of calcium channel blockers as maintenance therapy on preventing preterm birth after threatened preterm labour. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2013) and reference lists of retrieved studies. SELECTION CRITERIA: Randomised controlled trials of calcium channel blockers used as maintenance therapy to prevent preterm birth after threatened preterm labour, compared with placebo or no treatment. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of included studies. MAIN RESULTS: We included six trials that enrolled 794 women and their babies and all assessed nifedipine as calcium channel blocker maintenance therapy. The six trials were judged to be at a moderate risk of bias overall. No differences in the incidence of preterm birth (risk ratio (RR) 0.97; 95% confidence interval (CI) 0.87 to 1.09; five trials, 681 women), birth within 48 hours of treatment (RR 0.46; 95% CI 0.07 to 3.00; two trials, 128 women) or neonatal mortality (average RR 0.75; 95% CI 0.05 to 11.76; two trials, 133 infants) were seen when nifedipine maintenance therapy was compared with placebo or no treatment. No stillbirths were reported in the one trial that provided data for this outcome. No trials reported on longer-term follow-up of infants.Women receiving nifedipine maintenance therapy were significantly more likely to have their pregnancy prolonged (mean difference (MD) 5.35 days; 95% CI 0.49 to 10.21; four trials, 275 women); however, no differences between groups were shown for birth at less than 34 weeks' gestation, birth at less than 28 weeks' gestation, birth within seven days of treatment, or gestational age at birth. No significant differences were shown between the nifedipine and control groups for any of the secondary neonatal morbidities reported. Similarly, no significant differences were seen for the outcomes relating to the use of health services, except for in one trial, where infants whose mothers received nifedipine were significantly more likely to have a longer length of hospital stay as compared with infants born to mothers who received a placebo (MD 14.00 days; 95% CI 4.21 to 23.79; 60 infants). AUTHORS' CONCLUSIONS: Based on the current available evidence, maintenance treatment with a calcium channel blocker after threatened preterm labour does not prevent preterm birth or improve maternal or infant outcomes.

Magnesium maintenance therapy for preventing preterm birth after threatened preterm labour.

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.

Tocolytic therapy for acute preterm labor.

The pathophysiology leading to preterm labor is not well understood and often multifactorial; initiating factors include intrauterine infection, inflammation, ischemia, overdistension, and hemorrhage. Given these different potential causes, directing therapy for preterm labor has been difficult and suboptimal. To date, no single drug has been identified as successful in treating all of the underlying mechanisms leading to preterm labor. In addition, the methodology of many of the tocolytic studies is limited by lack of sufficient patient numbers, lack of comparison with a placebo, and inconsistent use of glucocorticoids. The limitations in these individual studies make it difficult to evaluate the efficacy of a single tocolytic by meta-analysis. Despite these limitations, the goals for tocolysis for preterm labor are clear: To complete a course of glucocorticoids and secure the appropriate level of neonatal care for the fetus in the event of preterm delivery. The literature demonstrates that many tocolytic agents inhibit uterine contractility. The decision as to which tocolytic agent should be used as first-line therapy for a patient is based on multiple factors, including gestational age, the patient's medical history, common and severe side effects, and a patient's response to therapy. In a patient at less than 32 weeks gestation, indomethacin may be a reasonable first choice based on its efficacy, ease of administration, and minimal side effects. Concurrent administration of magnesium for neuroprotection may be given. At 32 to 34 weeks, nifedipine may be a reasonable first choice because it does not carry the fetal risks of indomethacin at these later gestational ages, is easy to administer, and has limited side effects relative to beta-mimetics. In an effort to review a commonly faced obstetrical complication, this article has provided a summary of the most commonly used tocolytics, their mechanisms of action, side effects, and clinical data regarding their efficacy.

Tocolytics for preterm premature rupture of membranes.

BACKGROUND: In women with preterm labor, tocolysis has not been shown to improve perinatal mortality; however, it is often given for 48 hours to allow for the corticosteroid effect for fetal maturation. In women with preterm premature rupture of membranes (PPROM), the use of tocolysis is still controversial. In theory, tocolysis may prolong pregnancy in women with PPROM, thereby allowing for the corticosteroid benefit and reducing the morbidity and mortality associated with prematurity. OBJECTIVES: To assess the potential benefits and harms of tocolysis in women with preterm premature rupture of membranes. SEARCH STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (6 April 2011), CENTRAL (The Cochrane Library 2011, Issue 1), MEDLINE (1966 to 6 April 2011) and EMBASE (1974 to 6 April 2011). SELECTION CRITERIA: We included pregnant women with singleton pregnancies and PPROM (23 weeks to 36 weeks and six days). We included any tocolytic therapy compared to no tocolytic, placebo, or another tocolytic. DATA COLLECTION AND ANALYSIS: All review authors assessed the studies for inclusion. We extracted and quality assessed data. MAIN RESULTS: We included eight studies with a total of 408 women. Seven of the studies compared tocolysis to no tocolysis. One study compared nifedipine to terbutaline. Compared to no tocolysis, tocolysis was not associated with a significant effect on perinatal mortality in women with PPROM (risk ratio (RR) 1.67; 95% confidence interval (CI) 0.85 to 3.29). Tocolysis was associated with longer latency (mean difference (MD) 73.12 hours; 95% CI 20.21 to 126.03; three trials of 198 women) and fewer births within 48 hours (average RR 0.55; 95% CI 0.32 to 0.95; six trials of 354 women; random-effects, T(2) = 0.18, I(2) = 43%) compared to no tocolysis. However, tocolysis was associated with increased five-minute Apgar of less than seven (RR 6.05; 95% CI 1.65 to 22.23; two trials of 160 women) and increased need for ventilation of the neonate (RR 2.46; 95% CI 1.14 to 5.34; one trial of 81 women). In the subgroup analysis comparing betamimetic to no betamimetics, tocolysis was associated with increased latency and borderline significance for chorioamnionitis. Prophylactic tocolysis with PPROM was associated with increased overall latency, without additional benefits for maternal/neonatal outcomes. For patients with PPROM before 34 weeks, there was a significantly increased risk of chorioamnionitis in women who received tocolysis. However, neonatal outcomes were not significantly different. There were no significant differences in maternal/neonatal outcomes in subgroup analyses comparing cox inhibitor versus no tocolysis, calcium channel blocker versus betamimetic, antibiotic, corticosteroid or combined antibiotic/corticosteroid. AUTHORS' CONCLUSIONS: Our review suggests there is insufficient evidence to support tocolytic therapy for women with PPROM, as there was an increase in maternal chorioamnionitis without significant benefits to the infant. However, studies did not consistently administer latency antibiotics and corticosteroids, both of which are now considered standard of care.

Magnesium maintenance therapy for preventing preterm birth after threatened preterm labour.

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 STRATEGY: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (May 2010). 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, which recruited 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 (2 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 also compared with alternative treatments, was 5.00, 95% CI 0.25 to 99.16 (one trial, 50 infants). Women taking magnesium preparations were less likely to report palpitations or tachycardia than women receiving alternative therapies (RR 0.26, 95% CI 0.13 to 0.52, three trials, 237 women) but were much more likely to experience diarrhoea (RR 7.66, 95% CI 2.18 to 26.98, 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.