Search

A systematic literature review and meta-analysis was conducted to evaluate whether the administration of an oxytocin receptor antagonist (OTR-a) around embryo transfer is associated with live birth and pregnancy achievement in IVF treatment. Multiple databases were searched for randomized controlled trials (RCT) comparing the outcome of IVF treatment with administration of an OTR-a before, during or after embryo transfer versus administration of placebo/nil. The literature search identified 11 eligible RCT. The active compound was intravenous atosiban (n = 7), subcutaneous barusiban (n = 1) and oral nolasiban (n = 3). Clinical pregnancy rate was significantly higher in women receiving an OTR-a around embryo transfer (relative risk [RR] 1.31, 95% confidence interval [CI] 1.13–1.51, P = 0.0002, I2 = 61%, n = 11 studies, n = 3611); however, live birth rate was not statistically significantly affected (RR 1.09, 95% CI 0.98–1.20, P = 0.11, I2 = 25%, n = 5 studies, n = 2765). A sensitivity analysis on low risk of bias studies likewise indicates a higher clinical pregnancy chance (RR 1.11, 95% CI 1.01–1.22, P = 0.03, I2 = 5%, n = 5 RCT, n = 2765). OTR-a administration in IVF treatment has the potential to increase IVF efficacy, although the treatment effects observed so far are small and have not been sufficiently corroborated.

Background Embryo transfer without difficulty in a patient with cervical stenosis can be a great challenge for in vitro fertilization (IVF). We report a successful pregnancy following a frozen thawed embryo transfer after administration of an oxytocin antagonist at the same time as using a Foley catheter with cotton swab in a patient with refractory cervical stenosis. Case presentation A 40-year-old woman undergoing IVF. The patient’s previous embryo transfers were difficult. For every transfer, uterine manipulation was needed, force was required, and dilatation was necessary. A Foley catheter with a cotton swab was inserted into the cervical canal, atosiban was administered at the same time, and the Foley catheter was removed immediately before embryo transfer. A smooth transfer was performed without bleeding, force, uterine manipulation, or cervical dilator. The patient became pregnant and delivered by cesarean section at term. Conclusion This method is effective in performing atraumatic embryo transfer in patients with cervical stenosis.

Objectives This study aimed to generate baseline evidence regarding the effectiveness of atosiban in delaying delivery by ≥48 hours among pregnant women presenting with threatened preterm labour (TPL). The secondary objective was to assess the relationship between atosiban success and various perinatal factors and neonatal outcomes. Methods This retrospective study was conducted between June 2008 and May 2018 at the Sultan Qaboos University Hospital, Muscat, Oman. The medical records of all pregnant women who received atosiban between 24–34 gestational weeks for TPL during this period were reviewed. Results A total of 159 women were included in the study. Atosiban was successful in delaying delivery by ≥48 hours in 130 cases (81.8%). Approximately half of the women (50.9%) achieved uterine quiescence in

Background Increased insulin production and secretion by pancreatic β-cells are important for ensuring the high insulin demand during gestation. However, the underlying mechanism of β-cell adaptation during gestation or gestational diabetes mellitus (GDM) remains unclear. Oxytocin is an important physiological hormone in gestation and delivery, and it also contributes to the maintenance of β-cell function. The aim of this study was to investigate the role of oxytocin in β-cell adaptation during pregnancy. Methods The relationship between the blood oxytocin level and pancreatic β-cell function in patients with GDM and healthy pregnant women was investigated. Gestating and non-gestating mice were used to evaluate the in vivo effect of oxytocin signal on β-cells during pregnancy. In vitro experiments were performed on INS-1 insulinoma cells. Results The blood oxytocin levels were lower in patients with GDM than in healthy pregnant women and were associated with impaired pancreatic β-cell function. Acute administration of oxytocin increased insulin secretion in both gestating and non-gestating mice. A 3-week oxytocin treatment promoted the proliferation of pancreatic β-cells and increased the β-cell mass in gestating but not non-gestating mice. Antagonism of oxytocin receptors by atosiban impaired insulin secretion and induced GDM in gestating but not non-gestating mice. Oxytocin enhanced glucose-stimulated insulin secretion, activated the mitogen-activated protein kinase pathway, and promoted cell proliferation in INS-1 cells. Conclusions These findings provide strong evidence that oxytocin is needed for β-cell adaptation during pregnancy to maintain β-cell function, and the lack of oxytocin could be associated with the risk of GDM.

Objective: To compare the efficacy of atosiban with conventional treatment of the threatened preterm labor. Materials and methods: All the data of pregnant women with threatened preterm labor from January 1 to December 31, 2017, who received atosiban were collected. Pregnant women with conventional treatment (including β-agonists, indomethacin, magnesium sulphate and calcium channel blockers, alone or in combination) were used as control. Results: The proportion of women not requiring an alternative tocolytic treatment within 48 h and remaining undelivered was significantly higher in atosiban treatment group (89.3%; n = 25/28) compared with conventional treatment (24.2%; n = 8/33) (P

Objective The aim of this study is to assess the efficacy and safety of retosiban in spontaneous preterm labor (sPTL). Study Design Two multicenter, randomized, and double-blind trials compared retosiban with placebo and retosiban with atosiban in women with a singleton pregnancy and intact membranes in sPTL at 24 to 336/7 weeks' gestation. Coprimary endpoints in the placebo-controlled trial were time to delivery (TTD) or treatment failure (whichever occurred first) and neonatal composite morbidity and mortality. The primary endpoint of the atosiban comparator trial was TTD. Results The trials were terminated early because of slow recruitment. The placebo-controlled trial enrolled 23 participants (February 2016–July 2017; 2.6% of target);the atosiban-comparator trial enrolled 97 (March 2015–August 2017; 29% of target). Baseline participant characteristics were similar between treatments. In the placebo-controlled trial, mean gestational ages at randomization were 30.8 (retosiban, n = 10) and 30.5 weeks (placebo, n = 13), and mean times to delivery/treatment failure were 18.9 days (retosiban) and 11.1 days (placebo). Two and four neonates in the retosiban and placebo groups, respectively, had ≥1 component of the neonatal composite endpoint. In the atosiban-comparator trial, mean gestational age at randomization was 31.5 weeks (for both retosiban, n = 47, and atosiban, n = 50), and adjusted mean TTDs were 32.51 days (retosiban) and 33.71 days (atosiban; p > 0.05). Adverse events were no more common with retosiban than placebo or atosiban. Conclusion Despite considerable efforts to conduct two adequate and well-controlled studies in patients with sPTL, both studies were unable to recruit effectively and consequently terminated prematurely. Key factors negatively affecting participation were patient and physician resistance to use of a placebo comparator, lack of investigator consensus on diagnostic criteria and acceptance of protocol procedures, and ethics committee decisions. Meaningful cooperation between pharmaceutical companies, regulatory authorities, and the obstetric community is essential for future development of drugs to treat sPTL.

To assess the efficacy of atosiban versus ritodrine as tocolytics in external cephalic version (ECV).A prospective comparative trial was carried out in a tertiary hospital. 430 women with singleton breech pregnancies ≥36 weeks were recruited for ECV, 215 with ritodrine and 215 with atosiban as tocolytic agents. The efficacy, complications and perinatal outcomes were compared between both groups. The associations between variables were analyzed using the chi-square test (χThe overall ECV success rate was 47.9% (206/430), 46.0% in the atosiban group (99/215) and 49.8% in the ritodrine group (107/215). This difference showed no statistical significance (Atosiban and ritodrine showed similar efficacy as tocolytic agents in ECV, with no differences in complications and perinatal outcomes between these two agents.

We assessed the effect of atosiban on pregnancy outcomes following in vitro fertilization (IVF) treatment among infertile women requiring different numbers of embryo transfer (ET) cycles (i.e., one, two, and more than two ET cycles). A longitudinal cohort study was conducted by utilizing the data from the Assisted Reproductive Technology Center in a university tertiary hospital during 2007-2017. Patients receiving IVF treatment with at least one ET cycle were included. Pregnancy outcomes following IVF treatment, including biochemical, clinical, and ongoing pregnancies, were investigated. The association between atosiban and IVF pregnancy was assessed using logistic generalized estimating equation models, with adjustment for time-varying clinical characteristics (e.g., maternal age) across multiple ET cycles for an individual. 403 women with 838 ET cycles were included, where 165 patients required one ET cycle, 133 patients required two ET cycles (a total of 266 ET cycles), and 105 patients required more than two ET cycles (a total of 407 ET cycles). Atosiban use was not significantly associated with pregnancy outcomes among all study infertile women undergoing IVF treatment. However, the results for women requiring more than two ET cycles showed significantly increased pregnancy rates associated with atosiban use (i.e., odds ratios [95% confidence interval] of 4.40 [1.52, 12.73] and 2.85 [1.45, 5.60] for clinical and ongoing pregnancies, respectively). This association was not observed for the women requiring only one or two ET cycles. Atosiban is a potential treatment for enhancing IVF pregnancy, especially among infertile women requiring more than two ET cycles.

Objective To estimate the effectiveness of Atosiban in improving the outcome after embryo transfer. The effectiveness of embryo transfer per cycle is still relatively low. One possible explanation might be uterine contractility that expels the transferred embryos. Atosiban improved the outcome of embryo transfer by reducing uterine contractility. Methods Data sources: A systematic review of papers in English using MEDLINE and EMBASE (1990-2019). Search terms included Atosiban, embryo transfer. Study selection: We included studies that compared the outcomes of embryo transfer with Atosiban and a control group. Data Extracting: Independent extraction of papers by two authors, using predefined data fields, including study quality indicators. Results All pooled analyses were based on a fixed-effect model. Four randomised controlled trials, including 1,025 women, and two non-randomised trials, including 686 patients, met our inclusion criteria. In both studies, the heterogeneity was moderate. Atosiban increased clinical pregnancy rates regardless of the indication for ART or type of embryo transferred. Pooled OR in randomized controlled trials reached 1.47 (1.18-1.82), and in non-randomised controlled trials it reached 1.50 (95% CI 1.10-2.05). Conclusion Atosiban appears to increase the clinical pregnancy rates in women undergoing embryo transfer.

This study aimed to evaluate the effectiveness of intrapartum acute tocolysis for nonreassuring fetal heart rate tracing in decreasing the incidence of cesarean delivery. Secondary outcomes included modes of delivery other than cesarean delivery, successful acute tocolysis, time-to-delivery interval, and short-term perinatal outcomes.Searches were performed in MEDLINE/PubMed, Embase, Scopus, the Cochrane Central Register of Controlled Trials and Reviews, ClinicalTrials.gov, and the International Clinical Trials Registry Platform from the inception of each database until February 2022.Selection criteria included randomized controlled trials of laboring patients with singleton gestations randomized to receive intrapartum acute tocolysis for nonreassuring fetal heart rate tracing, as defined by the original trial.All analyses were done using an intention-to-treat approach, evaluating women according to the treatment group to which they were randomly allocated in the original trials. A frequentist network-meta-analysis was performed.Four randomized clinical trials were eligible, including 605 patients with nonreassuring fetal heart rate tracing and singleton gestations at gestational ages32 weeks. The cesarean delivery rate was similar among patients managed with different types of acute tocolysis. Acute tocolysis, compared with emergency delivery, was associated with improved neonatal acid-base status (notably decreasing the prevalence of base deficit12 mmol/L [beta-2 agonists odds ratio, 0.61; 95% confidence interval, 0.37-0.99] and the rate of neonatal intensive care unit admission [beta-2 agonists odds ratio, 0.42; 95% confidence interval, 0.22-0.78]) and with an increase in the time-to-delivery interval (beta-2 agonists mean difference, 17.62 minutes; 95% confidence interval, 15.66-19.58); there was no reduction of cesarean delivery rate, showing an increased rate with atosiban and beta-2 agonists.The cesarean delivery rate was not reduced by acute tocolysis when used for nonreassuring fetal heart rate tracing during labor. Acute tocolysis is associated with improved short-term fetal outcomes and safely increases the time-to-delivery interval.

Objective To evaluate the impact of atosiban as a tocolytic agent in patients treated with the fetoscopic endotracheal occlusion (FETO) procedure due to congenital diaphragmatic hernia (CDH). As premature birth after fetoscopy remains a serious concern, an effort to reduce prematurity is required. Methods A total of 43 patients with severe CDH treated with FETO were enrolled in this study. The study group consisted of 22 patients who received atosiban during the FETO procedure and a control group of 21 patients who did not receive atosiban during the FETO procedure. Demographic data, gestational age (GA) at delivery, cervical length and GA at premature rupture of membranes (PROM) were evaluated. Results The GA at delivery was significantly different between the two groups studied. The median GA at delivery was 32.6 and 34.5 weeks in the no-atosiban vs. atosiban groups, respectively (P = 0.013). The median cervical length was 29.9 and 31.2 mm for the no-atosiban and atosiban groups, respectively, and was not statistically significant (P = 0.28). There were no significant correlations between groups for the occurrence of PROM, GA at the time of PROM, duration of the procedures, parity, maternal body mass index (BMI) or age. In the univariate linear regression model, the only factor independently associated with GA at delivery was the use of atosiban during FETO procedures (β = 0.375; P Conclusion In cases of severe CDH treated with FETO, the use of atosiban as a tocolytic agent during the procedure prolonged pregnancy by 2 weeks. Cervical length, duration of FETO or maternal characteristics were not associated with GA at delivery.

Background Embryo transfer (ET) is a crucial step of in vitro fertilisation (IVF) treatment, and involves placing the embryo(s) in the woman's uterus. There is a negative association between endometrial wave-like activity (contractile activities) at the time of ET and clinical pregnancy, but no specific treatment is currently used in clinical practice to counteract their effects. Oxytocin is a hormone produced by the hypothalamus and released by the posterior pituitary. Its main role involves generating uterine contractions during and after childbirth. Atosiban is the best known oxytocin antagonist (and is also a vasopressin antagonist), and it is commonly used to delay premature labour by halting uterine contractions. Other oxytocin antagonists include barusiban, nolasiban, epelsiban, and retosiban. Administration of oxytocin antagonists around the time of ET has been proposed as a means to reduce uterine contractions that may interfere with embryo implantation. The intervention involves administering the medication before, during, or after the ET (or a combination). Objectives To evaluate the effectiveness and safety of oxytocin antagonists around the time of ET in women undergoing assisted reproduction. Search methods We searched the Cochrane Gynaecology and Fertility (CGF) Group trials register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and two trials registers in March 2021; and checked references and contacted study authors and experts in the field to identify additional studies. Selection criteria We included randomised controlled trials (RCTs) of the use of oxytocin antagonists for women undergoing ET, compared with the non-use of this intervention, the use of placebo, or the use of another similar drug. Data collection and analysis We used standard methodological procedures recommended by Cochrane. Primary review outcomes were live birth and miscarriage; secondary outcomes were clinical pregnancy and other adverse events. Main results We included nine studies (including one comprising three separate trials, 3733 women analysed in total) investigating the role of three different oxytocin antagonists administered intravenously (atosiban), subcutaneously (barusiban), or orally (nolasiban). We found very low- to high-certainty evidence: the main limitations were serious risk of bias due to poor reporting of study methods, and serious or very serious imprecision. Intravenous atosiban versus normal saline or no intervention We are uncertain of the effect of intravenous atosiban on live birth rate (risk ratio (RR) 1.05, 95% confidence interval (CI) 0.88 to 1.24; 1 RCT, N = 800; low-certainty evidence). In a clinic with a live birth rate of 38% per cycle, the use of intravenous atosiban would be associated with a live birth rate ranging from 33.4% to 47.1%. We are uncertain whether intravenous atosiban influences miscarriage rate (RR 1.08, 95% CI 0.75 to 1.56; 5 RCTs, N = 1424; I² = 0%; very low-certainty evidence). In a clinic with a miscarriage rate of 7.2% per cycle, the use of intravenous atosiban would be associated with a miscarriage rate ranging from 5.4% to 11.2%. Intravenous atosiban may increase clinical pregnancy rate (RR 1.50, 95% CI 1.18 to 1.89; 7 RCTs, N = 1646; I² = 69%; low-certainty evidence), and we are uncertain whether multiple or ectopic pregnancy and other complication rates were influenced by the use of intravenous atosiban (very low-certainty evidence). Subcutaneous barusiban versus placebo One study investigated barusiban, but did not report on live birth or miscarriage. We are uncertain whether subcutaneous barusiban influences clinical pregnancy rate (RR 0.96, 95% CI 0.69 to 1.35; 1 RCT, N = 255; very low-certainty evidence). Trialists reported more mild to moderate injection site reactions with barusiban than with placebo, but there was no difference in severe reactions. They reported no serious drug reactions; and comparable neonatal outcome between groups. Oral nolasiban versus placebo Nolasiban does not increase live birth rate (RR 1.13, 95% CI 0.99 to 1.28; 3 RCTs, N = 1832; I² = 0%; high-certainty evidence). In a clinic with a live birth rate of 33% per cycle, the use of oral nolasiban would be associated with a live birth rate ranging from 32.7% to 42.2%. We are uncertain of the effect of oral nolasiban on miscarriage rate (RR 1.45, 95% CI 0.73 to 2.88; 3 RCTs, N = 1832; I² = 0%; low-certainty evidence). In a clinic with a miscarriage rate of 1.5% per cycle, the use of oral nolasiban would be associated with a miscarriage rate ranging from 1.1% to 4.3%. Oral nolasiban improves clinical pregnancy rate (RR 1.15, 95% CI 1.02 to 1.30; 3 RCTs, N = 1832; I² = 0%; high-certainty evidence), and probably does not increase multiple or ectopic pregnancy, or other complication rates (moderate-certainty evidence). Authors' conclusions We are uncertain whether intravenous atosiban improves pregnancy outcomes for women undergoing assisted reproductive technology. This conclusion is based on currently available data from seven RCTs, which provided very low- to low-certainty evidence across studies. We could draw no clear conclusions about subcutaneous barusiban, based on limited data from one RCT. Further large well-designed RCTs reporting on live births and adverse clinical outcomes are still required to clarify the exact role of atosiban and barusiban before ET. Oral nolasiban appears to improve clinical pregnancy rate but not live birth rate, with an uncertain effect on miscarriage and adverse events. This conclusion is based on a phased study comprising three trials that provided low- to high-certainty evidence. Further large, well-designed RCTs, reporting on live births and adverse clinical outcomes, should focus on identifying the subgroups of women who are likely to benefit from this intervention.

Study question Does the administration of an oxytocin-receptor antagonist around time of embryo transfer in IVF impact the likelihood to achieve a clinical pregnancy? Summary answer Administration of oxytocin-receptor antagonists around embryo transfer increases the likelihood of clinical pregnancy achievement. What is known already Uterine contractions occurring around time of embryo transfer have been described as one possible mechanism of failure of implantation of an embryo in the context of in-vitro fertilization (IVF). Hence the utilization of oxytocin-receptor antagonists was evaluated in randomized clinical trials (RCT) as a therapeutic approach. The compound Atosiban was studied by most RCTs (summarized in Huang et al. 2017). Recently further studies have become available which also investigated the novel agents Barusiban and Nolasiban. This systematic review collates the evidence of all drugs functioning as oxytocin-receptor antagonists which have been investigated in RCTs on IVF treatment so far. Study design, size, duration Multiple literature databases were searched for randomized controlled studies comparing the outcome of IVF cycles with administration of an oxytocin-receptor antagonist in the time period before, during or after embryo transfer versus placebo or nil in IVF patients. Meta-analyses were performed using standard procedures in the software program RevMan v.5.4. All analyses were done per randomized patient, wherever feasible. Participants/materials, setting, methods Eleven RCTs were identified and included in the meta-analysis. Seven utilized the agent Atosiban, one Barusiban and three Nolasiban. These drugs were administered either intravenously, subcutaneously or orally. The patient populations were heterogenous (fresh cycle, frozen-thawed cycle, endometriosis, implantation failure or general IVF-population) between trials. Only four studies reported live birth rates whereas all RCTs reported clinical pregnancy rate. Main results and the role of chance Administration of an oxytocin-receptor antagonist around embryo transfer increases the likelihood of live birth (relative risk: 1.1, 95% CI: 0.99-1.22, p = 0.06, I2=31%, four RCTs, n = 2,510). Accordingly, the ongoing pregnancy rate is increased (relative risk: 1.14, 95% CI: 1.03-1.26, p = 0.01, I2=18%, four RCTs, n = 2,510) as well as the clinical pregnancy rate (relative risk: 1.31, 95% CI: 1.13-1.51, p = 0.0002, I2=61%, eleven RCTs, n = 3,611) by administration of an oxytocin-receptor antagonist. The risk to suffer a miscarriage, however, is not influenced by an oxytocin-receptor antagonist administration (relative risk: 0.90, 95% CI: 0.72-1.12, p = 0.35, I2=0%, seven RCTs, n = 2,936). The risk of multiple pregnancy is not different between groups (relative risk: 1.05 95% CI: 0.81-1.36, p = 0.73, I2=5%, seven RCTs, n = 3,014) as is the risk for an ectopic pregnancy (relative risk: 0.88 95% CI: 0.43-1.8, p = 0.73, I2=0%, four RCTs, n = 2,714). Limitations, reasons for caution Methodological rigor is heterogenous between trials and some of the evidence is of poor quality. Evaluation of included studies is still ongoing and queries are pending. Additionally, there is heterogeneity between patient populations and definition of outcomes; only four RCTs report ongoing pregnancies and live births. Wider implications of the findings The administration of oxytocin-receptor antagonists around embryo transfer increases the pregnancy rate and may be a promising approach to enhance the likelihood to achieve a live birth per embryo transfer. Trial registration number n.a.

At the 73rd Annual Congress of the Japan Society of Obstetrics and Gynecology, we discussed recent tocolytic treatments for the prevention of preterm birth with obstetricians from Korea and Taiwan. The rate of preterm birth in our countries has been increasing, and optimal tocolytic treatments are of great concern. Ritodrine hydrochloride was the first available drug for tocolysis in our countries and is often administered for over 48 h, although it is not recommended for maintenance therapy in Western countries. Meanwhile, there are differences in the use of other tocolytic drugs, based on approval of the drugs and the health insurance systems. Nifedipine and atosiban have not been considered first-line agents in Japan. The long-term use of unnecessary tocolysis should be avoided, and the introduction of other tocolytic drugs, including nifedipine or atosiban, should be discussed.

Background:Preterm birth is the major cause of perinatal mortality and morbidity worldwide. Attempts to reduce the burden may be proactive using biochemical or biophysical prediction and preventative measures. If these efforts fail, then the approach may have to be reactive using tocolytics to inhibit spontaneous preterm labour.Objective:We have reviewed the evidence concerning the safety and efficacy of various classes of tocolytic agents.Results:The evidence to support the use of magnesium sulfate or nitric oxide donors as a tocolytic is poor. Compared to placebo or no treatment, there is evidence to support the efficacy of calcium channel blockers (mainly nifedipine), prostaglandin synthetase inhibitors (mainly indomethacin and sulindac), oxytocin receptor antagonists (mainly atosiban) and β2-agonists (mainly ritodrine, terbutaline, salbutamol and fenoterol). Maternal safety concerns have reduced the use of β2-agonists. Fetal safety and gestational age restrictions have largely condemned prostaglandin synthetase inhibitors to second-line therapy. First-line therapy in Europe and other parts of the world outside the USA and Australia is limited to calcium channel blockers and oxytocin receptor antagonists. With respect to efficacy, atosiban and nifedipine are similar, but the robustness of the evidence favours atosiban. With respect to safety, atosiban is clearly the safest tocolytic as there are fetomaternal concerns with nifedipine, particularly in high daily doses.Conclusion:The perfect tocolytic that is uniformly effective and safe does not exist. Cost, licensing and informed consent are considerations involved in the choice. Efforts continue to develop and introduce other or better agents, including novel compounds such as progesterone, PGF2α antagonists and statins.

Background Two tocolytic drugs-atosiban and nifedipine-are currently used for first-line treatment of preterm labor (PTL). Objective To compare the efficacy and safety of atosiban with nifedipine for PTL treatment. Search strategy In May 2017, we searched PubMed, Scopus, Web of Science, and Cochrane Central Register of Controlled Clinical Trials with search terms including "nifedipine", "atosiban", and "preterm labor". Selection criteria Randomized controlled trials of women with PTL. Data collection and analysis Data were extracted for study design, patient characteristics, risk of bias domains, and study outcomes. A random-effects model was used to generate pooled risk ratios (RRs) and 95% confidence intervals (CIs). Results We included seven studies that enrolled 992 patients. There was no significant difference between atosiban and nifedipine for pregnancy prolongation of 48 hours or more regarding efficacy (RR 1.06, 95% CI 0.92-1.22; P=0.440) or effectiveness (0.93, 0.84-1.03; P=0.177). Pregnancy prolongation for 7 days or more also did not differ between groups for efficacy (RR 1.04, 95% CI 0.89-1.21; P=0.656) or effectiveness (0.91, 0.79-1.05; P=0.177). Atosiban-however-was associated with fewer maternal side-effects than nifedipine. Conclusion Atosiban resulted in fewer maternal side-effects than nifedipine, with no difference in pregnancy prolongation. PROSPERO registration: CRD42018090223.

Objective To assess the cost-effectiveness of treatment with nifedipine compared with atosiban in women with threatened preterm birth. Design An economic analysis alongside a randomised clinical trial (the APOSTEL III study). Setting Obstetric departments of 12 tertiary hospitals and seven secondary hospitals in the Netherlands and Belgium. Population Women with threatened preterm birth between 25 and 34 weeks of gestation, randomised for tocolysis with either nifedipine or atosiban. Methods We performed an economic analysis from a societal perspective. We estimated costs from randomisation until discharge. Analyses for singleton and multiple pregnancies were performed separately. The robustness of our findings was evaluated in sensitivity analyses. Main outcome measures Mean costs and differences were calculated per woman treated with nifedipine or atosiban. Health outcomes were expressed as the prevalence of a composite of adverse perinatal outcomes. Results Mean costs per patients were significantly lower in the nifedipine group [singleton pregnancies: euro34,897 versus euro43,376, mean difference (MD) -euro8479 [95% confidence interval (CI) -euro14,327 to -euro2016)]; multiple pregnancies: euro90,248 versus euro102,292, MD -euro12,044 (95% CI -euro21,607 to euro -1671). There was a non-significantly higher death rate in the nifedipine group. The difference in costs was mainly driven by a lower neonatal intensive care unit admission (NICU) rate in the nifedipine group. Conclusion Treatment with nifedipine in women with threatened preterm birth results in lower costs when compared with treatment with atosiban. However, the safety of nifedipine warrants further investigation. Tweetable abstract In women with threatened preterm birth, tocolysis using nifedipine results in lower costs when compared with atosiban.

Preterm birth is defined as delivery before 37 completed weeks of pregnancy, and it is the leading cause of neonatal morbidity and mortality. Oxidative stress is recognized as an important factor in the pathogenesis of premature labor. We conducted this analysis to investigate the safety of administration of the tocolytic drug Atosiban—a reversible, competitive antagonist of the oxytocin receptor in the treatment of preterm birth and its impact on the level of oxidative stress in pregnant women after 48 hours of tocolytic treatment. This prospective study was conducted between March 2016 and August 2017 at the Obstetric Clinic of the Polish Mother’s Memorial Hospital Research Institute. Total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI) values as well as 3-nitrotyrosine, carbonyl, and thiol group levels were measured using an ELISA test in serum and plasma of 56 pregnant women before and after 48 hours of continuous administration of Atosiban. We found that TAS levels decreased almost twice after the 48-hour drug administration (0.936 ± 0.360 mmol/L vs. 0.582 ± 0.305 mmol/L, P<0.001) while TOS increased from 18.217 ± 16.093 μmol/L to 30.442 ± 30.578 μmol/L (P<0.001). We also found a significant increase in OSI index—almost a threefold increase from 0.022 ± 0.022 to 0.075 ± 0.085, P<0.001. In addition, statistically significant differences in the level of carbonyl groups were found. It increased from 65.358 ± 31.332 μmol/L to 97.982 ± 38.047 μmol/L (P<0.001), which indicates increased oxidation of plasma proteins. Furthermore, patients who gave birth prematurely had higher levels of TOS after a 48-hour drug administration than the second group with labor after 37 weeks of pregnancy (42.803 ± 34.683 μmol/L vs. 25.792 ± 27.821 μmol/L, P<0.031). The obtained results clearly indicate that pregnant women during tocolytic treatment with Atosiban are in a state of increased oxidative stress and occurrence of preterm birth can be associated with this phenomenon. This trial is registered with NCT03570294.

Objectives To compare the effects of atosiban (oxytocin antagonist) on uterine peristalsis and pregnancy outcomes in the frozen embryo transfer (FET) cycle. Setting Srinagarind Hospital, a university hospital, Khon Kaen, Thailand. Design A randomized, double-blinded, controlled trial. Methods Fifty infertile women were randomized into the atosiban (n = 25) and placebo group (n = 25). Women in the study group received intravenous atosiban 6.75 mg, 30 min before embryo transfer, and continued infusion at 18 mg/h for 1 h. The dose was reduced to 6 mg/h for another 2 h. Saline solution was applied in the placebo group. The uterine peristalsis frequency was measured by transvaginal ultrasound 30 min before and 3 h after the embryo transfer. Results The respective mean baseline uterine peristalsis frequency (time) in the atosiban and placebo group was 10.3 ± 2.4 and 9.2 ± 3.4. The respective duration of uterine peristalsis in the atosiban and placebo group after receiving the intervention was reduced to 7.9 ± 2.1 and 6.9 ± 2.7. The implantation rate and clinical pregnancy rate were not statistically significant different between atosiban group and placebo group (37.5% versus 31.0%, RR 1.21, 95%CI: 0.60–2.44 and 44% versus 36%, RR 1.22, 95%CI: 0.62–2.42, respectively). Subgroup analysis indicated that the clinical pregnancy rate in those >35 years of age was not significantly different between both groups (31.6% and 18.8 %, RR 1.68, 95%CI: 0.50–5.68). Conclusion Adding atosiban in FET did not reduce uterine peristalsis but may benefit the advanced age group.

BACKGROUND Premature labor is an important cause of infant death and long-term disability. This study aimed to explore the safety and effectiveness of combining the tocolytic agents atosiban and ritodrine to extend gestation. MATERIAL AND METHODS The study included 52 patients with late threatened abortion and threatened premature labor between 20⁰⸍⁷ and 33⁶⸍⁷ weeks' gestation who were administrated continuous tocolytic agents for 48 h. Patients were divided into a research group receiving ritodrine combined with atosiban, owing to having no response to ritodrine alone (n=30), and a control group receiving ritodrine alone (n=22). The mean infusion rate and duration of tocolytic administration, gestation extension, pregnancy outcomes, and adverse effects were recorded. Routine blood tests, including C-reactive protein, and cultures for leukorrhea, candida, and mycoplasma were performed before and 1 week after treatment. RESULTS Patients receiving ritodrine with atosiban had a mean gestation extension of 42.53±31.70 days. The extension of gestation of the research group was statistically shorter than that of the control group (P0.05). The fetal loss rate, newborn birth weight, and Apgar score at 1 min were similar between the 2 groups (all, P0.05). The research group had a lower incidence of palpitations than the control group (P0.05). CONCLUSIONS For patients with late threatened abortion or threatened premature labor not controlled with ritodrine alone, ritodrine combined with atosiban extends gestation and improves pregnancy outcomes. For patients with abnormal uterine contractions, routine testing for reproductive tract infection should be performed. When infection is present, anti-infective therapy should be administered.

Introduction Breech/transverse presentation is responsible for about 30–50 % of cesarean sections in the world. Cesarean section carries a five-fold greater morbidity than vaginal delivery, deeply impacting on women’s health. External Cephalic Version (ECV) is an external manipulation used to convert a non-cephalic to a cephalic presentation. The use of tocolysis might facilitate this procedure; however, it is still controversial which drug should be considered as first choice. Objective To assess the effectiveness of tocolysis with atosiban, a competitive oxytocin receptor antagonist, in order to increase the rate of successful ECV. Study design Nine databases (including MEDLINE, CINAHL, LILACS, EMBASE, Scopus, ClinicalTrials.gov, Scielo, PROSPERO, Cochrane at CENTRAL) were searched from the inception to August 2020 using a combination of MeSH terms and keywords regarding “atosiban” and “external cephalic version”. We included trials of women with a singleton pregnancy who reached at least 36 weeks of gestation and were scheduled to ECV and tocolysis with atosiban (intervention group) compared to beta-agonists or other drugs (control group). The primary outcome was the incidence of successful ECV. Summary measures were reported as relative risk (RR) with 95 % confidence interval (CI). Data collection and analysis Four studies (1534 women) were eligible for analysis. ECV success rate was significantly lower in women randomized to atosiban (36.7 % vs 45.3 %; RR 0.78 [95 % CI 0.6 to 0.98]). Cesarean section and vaginal delivery rates did not differ between intervention and control group ((59.8 % vs 52.6 %; RR 1.17 [0.98–1.38] and (38.6 % vs 45.0 %; RR 0.83 [95 % CI 0.69–1.01] respectively). Cephalic (36.9 % vs 44.6 %; RR 0.81 [95 % CI 0.65 to 1.01], or breech/transverse presentation at labor (63.4 % vs 55.1 %; RR 1.18 [95 % CI 0.99–1.40]), APGAR score less than 7 at 5 min (1.6 % vs 2.0 %; RR 1.14 [95 % CI 0.27–4.73], NICU admissions (44.2 % vs 48.1 %; RR 0.92 [95 % CI 0.58–1.46] and Umbilical cord pH were similar in both groups. Drug-related side effects were lower in women randomized to atosiban, compared with control group (16.0 % vs 42.9 %; RR 0.38 [95 % CI 0.31 to 0.47]. Conclusion The use of atosiban for tocolysis does not improve the rate of successful ECVs when compared to beta-agonists. However, atosiban was associated with a significantly lower incidence of side effects and comparable cesarean section rates.

The aim of the present systematic review and meta-analysis was to assess the effect of the different therapeutic options for repeated embryo implantation failure (RIF) on a subsequent IVF cycle outcome. Twenty-two RCTs and nineteen observational studies were included. Pooling of results showed a beneficial effect of intrauterine PBMC infusion on both CPR (RR 2.18; 95% CI 1.58–3.00; p

Introduction: In women with preterm ruptured membranes and contractions, the administration of tocolysis is controversial. This study compares tocolysis with no tocolysis in women with threatened preterm birth and ruptured membranes. Objective: To compare tocolysis with no tocolysis in women with threatened preterm birth and ruptured membranes. Study design: Data from the APOSTEL III RCT was combined with data from the National Maternity Hospital, Dublin. In the APOSTEL III trial, women with threatened preterm birth were randomized to atosiban or nifedipine. Patient data from Ireland were obtained from a cohort of women with threatened preterm birth with ruptured membranes. The Irish women received no tocolytic treatment. Only women with ruptured membranes and contractions were selected. We studied women with singleton or twin pregnancies and a gestational age between 25+0 and 33+6 weeks. Propensity score matching was performed to create comparable groups. Primary outcome was a composite adverse neonatal outcome. Secondary outcomes were individual components of the primary outcome, as well as neonatal intensive care unit (NICU) admission, gestational age at delivery, prolongation of pregnancy and mode of delivery. Results: 153 women from the Apostel III trial were compared with 51 eligible women of the Irish cohort. We could match 46 women who received tocolysis and 46 women who received no tocolysis. All women had ruptured membranes. Maternal age, BMI, parity and gestational age at study entry were comparable between the groups after matching. There were no statistically significant differences in neonatal composite outcome (9.6 % in the tocolysis group versus 18 % in the control group, OR 0.46, 95 % CI 0.13−1.63). We found a lower incidence of NICU admission in the tocolysis group (63 %) than in the control group (94 %; OR 0.11, 95 % CI 0.03−0.41), which could be explained by differences in national admission policies. There were no statistically significant differences between tocolysis and no tocolysis in any of the other outcomes including sepsis, gestational age at delivery and time to delivery. Conclusion: In this propensity score analysis of women with threatened preterm birth and ruptured membranes, tocolytic therapy did not alter composite adverse neonatal outcome or time to delivery.

Introduction The breech presentation represents 4,7% of deliveries at term. There is a method of external cephalic version (ECV) performed from 36 weeks of gestation. French guidelines for the clinical practice of ECV were published in 2020. Objective To evaluate the national practices of ECV in French maternity units, especially on the use of tocolysis, 1 year after publication of the French clinical recommendations guidelines by the French national college of obstetricians and gynecologists (CNGOF). Methods Data self-reported for this national descriptive study were collected from March to May 2021 by an online questionnaire distributed to all French maternities. The 25 items of the questionnaire collected information of maternity units, the general practice of ECV, use or not of tocolysis for ECV attempt and the relevance of a prospective study. Results Of the 517 French maternity units, 150 (29%) responded to the online survey. 95,3% systematically performed ECV. A Kleihauer test was routinely performed in 71 units (49.7%). A tocolysis was associated with ECV attempt in 52.4% of cases. The drugs used were intravenous atosiban (30,7%), mainly in levels 2b and 3 maternity units, intravenous salbutamol (24%), other mode of administration of salbutamol (14,7%) and oral nifedipine (22,6%) mainly in levels 1 and 2a maternity units. Adverse effects were described in 20%, mainly with the use of salbutamol (73,3%). Conclusions 52.4% of the French maternity units surveyed used tocolysis for the ECV attempt, although it is systematically recommended. The choice of tocolytic drug differed according to the maternity units.

IntroductionPreterm birth complicates >15 million pregnancies annually worldwide. In many countries, women who present with signs of preterm labour are treated with tocolytics for 48 hours. Although this delays birth, it has never been shown to improve neonatal outcome. In 2015, the WHO stated that the use of tocolytics should be reconsidered and that large placebo-controlled studies to evaluate the effectiveness of tocolytics are urgently needed.Methods and analysisWe designed an international, multicentre, randomised, double-blinded, placebo-controlled clinical trial. Women with threatened preterm birth (gestational age 30–34 weeks), defined as uterine contractions with (1) a cervical length of < 15 mm or (2) a cervical length of 15–30 mm and a positive fibronectin test or (3) in centres where cervical length measurement is not part of the local protocol: a positive fibronectin test or insulin-like growth factor binding protein-1 (Actim-Partus test) or (4) ruptured membranes, will be randomly allocated to treatment with atosiban or placebo for 48 hours. The primary outcome is a composite of perinatal mortality and severe neonatal morbidity. Analysis will be by intention to treat. A sample size of 760 participants (380 per group) will detect a reduction in adverse neonatal outcome from 11.95% to 6% (alpha error 0.05, beta error 0.2). A cost-effectiveness analysis will be performed from a societal perspective.Ethics and disseminationThis study has been approved by the Research Ethics Committee (REC) of the Amsterdam University Medical Centres, location AMC, as well as the REC’s in Dublin and the UK. The results will be presented at conferences and published in a peer-reviewed journal. Participants will be informed about the results.Trial registration numberNederlands Trial Register (Trial NL6469).

Background The herbal medicine Bryophyllum pinnatum has been used as a tocolytic agent in anthroposophic medicine and, recently, in conventional settings alone or as an add-on medication with tocolytic agents such as atosiban or nifedipine. We wanted to compare the inhibitory effect of atosiban and nifedipine on human myometrial contractility in vitro in the absence and in the presence of B. pinnatum press juice (BPJ). Methods Myometrium biopsies were collected during elective Caesarean sections. Myometrial strips were placed under tension into an organ bath and allowed to contract spontaneously. Test substances alone and at concentrations known to moderately affect contractility in this setup, or in combination, were added to the organ bath, and contractility was recorded throughout the experiments. Changes in the strength (measured as area under the curve (AUC) and amplitude) and frequency of contractions after the addition of all test substances were determined. Cell viability assays were performed with the human myometrium hTERT-C3 and PHM1–41 cell lines. Results BPJ (2.5 μg/mL), atosiban (0.27 μg/mL), and nifedipine (3 ng/mL), moderately reduced the strength of spontaneous myometrium contractions. When BPJ was added together with atosiban or nifedipine, inhibition of contraction strength was significantly higher than with the tocolytics alone (p = 0.03 and p Conclusions BPJ enhances the inhibitory effect of atosiban and nifedipine on the strength of myometrial contractions, without affecting myometrium tissue or cell viability. The combination treatment of BPJ with atosiban or nifedipine has therapeutic potential.

Oxytocin is a hormone involved in the mechanism of breastfeeding, uterine contractions, and social relationships. Atosiban (competitive oxytocin antagonist) is one of the most commonly used tocolytics for the threat of preterm labor in Europe. The aim of this study is to determinate if the administration of atosiban has any influence in the type of feeding in the term newborn at discharge. The secondary objective is to verify its effectiveness for the prevention of preterm delivery and in the possibility of applying treatment to complete lung maturation.Retrospective cohort study carried out in a tertiary University Hospital distinguished by WHO-UNICEF as a Baby-Friendly Hospital Initiative. The analysis included 264 women exposed to atosiban during a period of 4 years. One hundred met inclusion criteria. Unexposed infants born right after and before the exposed ones were selected as the not exposed subgroup (n = 200).Among women treated with atosiban, 82% maintained exclusively breastfed (EBF), 8% had mixed breastfeeding, and 10% had formula feeding at discharge. In the nonexposed group, 82% maintained EBF, 9.5% had mixed breastfeeding, and 8.5% had formula feeding at discharge (p = 0.84). 97.5% of pregnant women treated with atosiban received corticosteroid for lung maturation, and 49.5% completed gestation with term newborns.There were no significant differences in the type of feeding at discharge between the atosiban group and the nonexposed group. In most cases, the administration of tocolytic therapy allowed to complete lung maturation.

Background A hypothesis of preterm parturition is that the pathogenesis of spontaneous preterm birth (sPTB) may be associated with an inflammatory process. Based on this theory, we have hypothesized that an inflammatory biomarker, procalcitonin (PCT), may be a good predictive marker of sPTB at the admission for threatened preterm labour (TPL). The present study was aimed to investigate the association between serum PCT and sPTB in women with TPL and to evaluate whether PCT levels may predict sPTB in women with TPL within 7 or 14 days. Methods In a prospective observational laboratory-based study, women with singleton pregnancies, TPL between 24 and 36 weeks and intact membranes, were enrolled between January 2014 and June 2016. Participants received routine medical management of TPL (tocolysis with atosiban, antenatal corticosteroids, and biological tests at admission (C-reactive protein, white blood cell count, and PCT measured on electrochemiluminescence immunoassay)). The primary endpoint was sPTB before 37 weeks of gestation. The value of serum PCT levels to predict sPTB within 7 or 14 days were evaluated using receiver-operating curves (ROC) analysis. Results A total of 124 women were included in our study. PCT levels did not statistically differ between women with sPTB (n = 30, 24.2%) and controls (n = 94) (median in ng/mL [interquartile range]: 0.043 [0.02–0.07] compared to 0.042 [0.02–0.13], respectively; P = 0.56). PCT levels did not also statistically differ between women with sPTB within 7 days (n = 7, 5.6%) or 14 days (n = 12, 9.7%) after testing and controls. Moreover, subgroup analysis revealed no difference among PCT levels at admission between 24 and 28 weeks, between 28 and 32 weeks and over 32 weeks, and controls. On the basis of the receiver-operating characteristic curve, the highest sensitivity and specificity corresponded to a PCT concentration of 0.038 ng/mL, with poor predictive values for sPTB within 7 or 14 days. Conclusion Serum PCT was not relevant to predict sPTB within 7 or 14 days in women admitted with TPL between 24 and 36 weeks, and thus it is not a suitable biological marker to confirm the hypothesis of an inflammatory process associated with preterm parturition. Trial registration Clinicaltrials.gov (NCT01977079), Registered 24 October 2013.

The aim of the study was to compare the efficacy and safety of tocolytic agents - atosiban and hexoprenaline.Patients and methods: The study included 119 pregnant women with threatening preterm labour between 28 to 34 weeks of gestation. Sixty two pregnant received 62 tocolysis by hexoprenaline and fifty seven - atosiban. There were no differences in the clinical condition of pregnant women and features of preterm labour among groups before start of the tocolysis.The degree of effectiveness is determined by the duration of the pregnancy prolongation (48 hours, 7 days, more than 14 days).Results: 9 women of 62 that received hexoprenaline tocolysis (22,6%), and 2 – atosiban (3.5%) failed to prolong the pregnancy for more than 48 hours (p < 0,05). Additionally, 5 women of the hexoprenaline group had premature labour within the first week from the treatment start and eight within 7-14 days. In the group of women with an effective atosiban tocolysis all births took place in a range of more than 7 days from the beginning of tocolysis. Four woman in hexoprenaline group received one repeated course of therapy with this drug (without a loading dose) for 24 hours. In atosiban group full repeated course was conducted in the two cases. Full-term gestation births occurred in 14 women (22.6%) after hexoprenaline tocolysis and in 19 (33.3%) – atosiban (p > 0,05%). On average, atosiban tocolysis allowed to prolong pregnancy by 6.5 days longer than hexoprenaline (p < 0,05).Conclusion: The results of study has shown that atosiban is more effective than hexoprenaline in pregnancy prolongation for more than 48 hours in threatening preterm labor.

Recent warnings postulate a possible damaging effect of volatile anesthetics on the fetus. In our archive of fetal surgeries, we found wide variation in dosing of volatile anesthetics during spina bifida surgeries. We hypothesized that there was an association between volatile anesthetic exposure and uterine activity.Sixty anesthesia records from spina bifida operations were assessed. We analyzed the course of the administered volatile anesthetic during surgery and calculated from each patient's anesthesia record the volatile anesthetic exposure expressed in vol%h. We divided the records into two post hoc groups of the 20 lowest exposure (Group L) versus the 20 highest exposure (Group H), and compared them for uterine activity and fetal heart rate.The number of contractions per hour was significantly greater in Group H (mean 1.3, SD ± 1.2) compared with Group L (mean 0.5, SD ± 0.6, P=0.049). There was no difference between the groups for the administration of the tocolytic drug atosiban (P=0.29). The course of the mean arterial pressure did not significantly differ but group H needed significantly more vasoactive medication (P0.05).We found that a lower intra-operative volatile anesthetic exposure than recommended in the MOMS-trial (i.e.2.0 minimum alveolar concentration [MAC]) was not associated with an increase in intra-operative uterine activity. This is an indication that during spina bifida surgery, 2.0 MAC may not be necessary to avoid potentially harmful uterine activity.

One of the most established roles of oxytocin (OT) is in inducing uterine contractions and labor. Apart from inducing contractions, our recent studies showed that OT can also activate proinflammatory pathways in both human myometrial and amnion cells, which suggests that the proinflammatory role of OT should be taken into account when developing tocolytics targeting the OT/oxytocin receptor (OTR) system. The OTR antagonist, atosiban, is currently used therapeutically for the treatment of preterm labor. We previously showed that atosiban fails to inhibit the proinflammatory effects of OT in human amnion; atosiban alone activates nuclear factor-κB (NF-κB) and mitogen activated protein kinases, thus upregulating downstream prolabor genes. In contrast with our findings with atosiban, the presence of the orally active OTR antagonist, nolasiban, reduced the effect of OT on NF-κB and p38 kinase activation in both myometrial and amnion cells. Consistent with the activation of these inflammatory mediators, OT led to increases in the expression of cyclooxygenase-2 and phosphorylated cytosolic phospholipase A2, which was reflected in prostaglandin E2 synthesis. Inhibition of NF-κB activation by nolasiban also translated to suppression of downstream prolabor gene expression, such as cyclooxygenase-2, C-C motif chemokine ligand 2, interleukin-6, and interleukin-8. We also demonstrated that nolasiban treatment alone has no significant stimulatory effect on both the myometrium and amnion. In conclusion, our findings indicate that nolasiban possesses promising potential as a novel tocolytic agent for both acute and maintenance therapy, as it inhibits both myometrial contractions and the proinflammatory effects of OT without the biased agonist effects.

The aim of the study was to compare the efficacy of tocolytic agents - hexoprenaline and atosiban taking into account the gestational age. Patients and methods . The study included 147 pregnant women with threatening preterm labour between 28 to 33 weeks of gestation. Seventy-three pregnant received tocolysis by hexoprenaline (36 of them before 28 weeks of gestation and 37 – 32 weeks and more) and 74 – atosiban (39 of them before 28 weeks of gestation and 35–32 weeks and more). There were no differences in the clinical condition of pregnant women and features of preterm labour among groups before start of the tocolysis. The degree of effectiveness is determined by the duration of the pregnancy prolongation (48 hours, 7 days, more than 14 days). Results . Depending on the gestational age women that received hexoprenaline tocolysis prolonged pregnancy for 48 hours in 80,6% and 81,1%, whereas in the treatment with atosiban in 94,9% and 100%. Full-term gestation births occurred in 24,3% after hexoprenaline tocolysis at 32 weeks and more and in 51,4% with – atosiban (p < 0,05%). On average, atosiban tocolysis allowed to prolong pregnancy by 6–10 days longer than hexoprenaline (p < 0,05). Conclusion : The results of study have shown that atosiban was more effective tocolytic than hexoprenaline in the treatment of threatening preterm labor in both 28-32 and 32 or more weeks of gestation. The efficacy of atosiban slightly increased with gestational age from 28 to 33 weeks.

Ethnopharmacological relevance In folklore medicine Ananas comosus (pineapple) is reputed to act as an abortifacient and in expectant women as a means of inducing labor. Several reports have claimed abortifacient property of A. comosus fruit (ripe or unripe). Ripe fruit has been used orally as traditional medicine in inducing abortion in Kerala state of India while the juice of unripe fruit was used for abortion in Bangladesh. However, scientific evidence supporting the efficacy of pineapple extracts in inducing uterine contractions is clearly lacking. Aim of the study This study investigated the pharmacological effects of different fractions of pineapple extract with a range of maturities to identify the most potent uterotonic fraction. Materials and Methods The ethanolic crude extracts of pineapple (edible part) were prepared and fractionated through a series of liquid-liquid partitions. Fractions were separately tested on isolated uterine muscle from pregnant SD rats and human pregnant myometrium, which were cut into strips along the longitudinal axis of uterus. The strips were mounted vertically in organ baths (37 °C) and exposed to cumulative addition of fractions (0.1–10 mg ml−1), serotonin (0.05–5 µM) and different inhibitors to delineate the mechanism of action of the active ingredients of the extract. Results Aqueous fraction (F4) possesses uterine stimulant property which was blocked by verapamil but unaffected by indomethacin, prazosin and atosiban. Notably, ketanserin (10 µM) diminished the maximal contractile response induced by both F4 and 5HT by 74.3% and 92.1% respectively. Conclusions These results may indicate the presence of 5HT or 5HT-like compound(s) and serotonergic pathways may contribute to the uterotonic activity of pineapple extract.

Introduction: Tocolytics may cause changes in fetal heart rate (HR) pattern, while fetal heart rate variability (HRV) is an important marker of fetal well-being. We aim to systematically review the literature on how tocolytic drugs affect fetal HRV.Materials and methods: We searched CENTRAL, PubMed and EMBASE up to June 2016. Studies published in English, using computerized or visual analysis to describe the effect of tocolytics on HRV in human fetuses were included. Studies describing tocolytics during labor, external cephalic version, pre-eclampsia and infection were excluded. Eventually, we included six studies, describing 169 pregnant women.Results: Nifedipine, atosiban and indomethacin administration show no clinically important effect on fetal HRV. Following administration of magnesium sulfate decreased variability and cases of bradycardia are described. Fenoterol administration results in a slight increase in fetal HR with no changes in variability. After ritodrine administration increased fetal HR and decreased variability is seen. The effect of co-administration of corticosteroids should be taken into account.Conclusion: In order to prevent iatrogenic preterm labor, the effects of tocolytic drugs on fetal HRV should be taken into account when monitoring these fetuses.Keywords: Tocolytic therapy, calcium channel blocker, oxytocin receptor antagonist, prostaglandin antagonist, beta-adrenergic agonist, fetal heart rate variability

Objectives To measure the tocolytic effect of the combination of the oxytocin receptor antagonist atosiban with the β-mimetic agent fenoterol on human myometrium of pregnant women. Methods An in vitro study of contractility in human myometrium at the Laboratory of the Department of Obstetrics, University Hospital of Zürich, Switzerland, was performed. Thirty-six human myometrial biopsies were obtained during elective caesarean sections of singleton pregnancies at term. Tissue samples were exposed to atosiban, fenoterol and the combination of atosiban with fenoterol. Contractility was measured as area under the curve during 30 min of spontaneous contractions. The effect of treatment was expressed as the percentage of change from basal activity during 30 min of exposure. Differences were calculated using a paired Wilcoxon signed-rank test. An additive effect of dual tocolysis was assumed when no significant difference was detected between the observed and expected inhibition of dual tocolysis. When inhibition was greater or lower than expected, the dual combination was characterised as “synergistic” or “antagonistic”, respectively. Results Atosiban and fenoterol alone suppressed contractions by a median of 43.2% and 29.8%, respectively. The combination of atosiban plus fenoterol was measured at a level of 67.3% inhibition. There was no significant difference in the expected (63.2%) and observed inhibition effect of dual tocolysis (P=0.945). Conclusion This study demonstrated an additive effect of dual tocolysis of atosiban and fenoterol on human myometrium in vitro, but no synergistic or antagonistic effect.