Improvement of early miscarriage rates in women with adenomyosis via oxytocin receptor antagonist during frozen embryo transfer-a propensity score-matched study.

BACKGROUND: Dysfunctional uterine peristalsis seems to play a pivotal role in hindering embryo implantation among women diagnosed with adenomyosis. This research aims to investigate whether administering an oxytocin receptor antagonist during a frozen embryo transfer (FET) cycle using a hormone replacement therapy (HRT) protocol can enhance in vitro fertilization (IVF) outcomes for infertile women affected by adenomyosis. METHODS: Between January 2018 and June 2022, our reproductive center conducted IVF-FET HRT cycles for infertile women diagnosed with adenomyosis. Propensity score matching was employed to select matched subjects between the two groups in a 1:1 ratio. Following this, 168 women received an oxytocin receptor antagonist during FET, constituting the study group, while the matched 168 women underwent FET without this antagonist, forming the control group. We conducted comparative analyses of baseline and cycle characteristics between the two groups, along with additional subgroup analyses. RESULTS: The study group exhibited notably lower rates of early miscarriage compared to the control group, although there were no significant differences in clinical pregnancy rates, ongoing pregnancy rates, and live birth rates between the two groups. Multivariate analysis revealed a negative correlation between the use of oxytocin receptor antagonists and early miscarriage rates in women with adenomyosis. Subgroup analyses, categorized by age, infertility types, and embryo transfer day, showed a substantial decrease in early miscarriage rates within specific subgroups: women aged ≥ 37 years, those with secondary infertility, and individuals undergoing day 3 embryo transfers in the study group compared to the control group. Furthermore, subgroup analysis based on adenomyosis types indicated significantly higher clinical pregnancy rates, ongoing pregnancy rates and live birth rates in the study group compared to the control group among women with diffuse adenomyosis. CONCLUSIONS: Administering an oxytocin receptor antagonist during FET may reduce the early miscarriage rates in women with adenomyosis.

Estimation of udder emptying based on milk constituents of strip samples after milking.

Milk ejection disorders were induced by oxytocin receptor blockade. We tested the hypothesis that the degree of udder emptying at incomplete milk ejection can be estimated based on the concentration of various milk constituents in different milk fraction samples. To induce different levels of spontaneous udder emptying (SUE) 10 Holstein dairy cows were milked either with or without i.v. injection of the oxytocin receptor blocking agent atosiban (ATO). In ATOearly, 12 µg/kg BW ATO was injected immediately before and in ATOlate directly after a 1-min manual udder preparation. The normal milking routine served as the control treatment. In all 3 treatments the udder was completely emptied by the i.v. injection of 10 IU oxytocin (OT) at the end of spontaneous milk flow. During all experimental milkings 4 milk samples were taken in all treatments: at the start of udder preparation (foremilk; FM), immediately after cessation of spontaneous milk flow and cluster detachment by hand stripping (strip milk; SM), from spontaneous removed milk in bucket 1 (milk before OT; MBOT) and from the milk obtained after OT injection in bucket 2 (milk after OT; MAOT). Fat, protein, lactose, and electrolytes (Na, Cl, and K) were measured in each milk sample. In addition, electrical conductivity (EC) was determined in parallel to continuous milk flow recording. The treatments induced individual degrees of SUE; therefore, the final evaluations of data were based on SUE classes instead of treatments. The most pronounced differences of milk constituents at different degrees of SUE were found for the milk fat content. The fat content of SM and MBOT remained almost unchanged up to 60% SUE, but was considerably higher if >80% of the milk was spontaneously removed. The concentrations of Na and Cl were highest and of K lowest if less than 20% of milk was received in the different samples. The EC was higher in SM and MBOT if <20% of milk was received. In conclusion, the blockade of the OT effect influences primarily the fat content, which confirmed an OT-induced fat secretion during milking. Similar effects are likely found in situations of disturbed milk ejections, caused by a lack of or reduced release of OT in response to different degrees of tactile udder stimulation. Our results show that the measurement of fat content and the EC in SM samples collected after cluster detachment can be used to estimate the completeness of udder emptying.

Impacts of Tocolytics on Maternal and Neonatal Glucose Levels in Women With Gestational Diabetes Mellitus.

BACKGROUND: We investigated the impacts of tocolytic agents on maternal and neonatal blood glucose levels in women with gestational diabetes mellitus (GDM) who used tocolytics for preterm labor. METHODS: This multi-center, retrospective cohort study included women with GDM who were admitted for preterm labor from twelve hospitals in South Korea. We excluded women with multiple pregnancies, anomalies, overt DM diagnosed before pregnancy or 23 weeks of gestation, and women who received multiple tocolytics. The patients were divided according to the types of tocolytics; atosiban, ritodrine, and nifedipine group. We collected baseline maternal characteristics, pregnancy outcomes, maternal glucose levels during hospitalization, and neonatal glucose levels. We compared the frequency of maternal hyperglycemia and neonatal hypoglycemia among three groups. A multivariate logistic regression analysis was performed to evaluate the contributing factors to the occurrence of maternal hyperglycemia and neonatal hypoglycemia. RESULTS: A total of 128 women were included: 44 (34.4%), 51 (39.8%), and 33 (25.8%) women received atosiban, ritodrine, and nifedipine, respectively. Mean fasting blood glucose (FBG) (112.3, 109.6, and 89.5 mg/dL, P < 0.001) and 2-hour postprandial glucose (PPG2) levels (145.4, 148.3, and 116.5 mg/dL, P = 0.004) were significantly higher in atosiban and ritodrine group than those in nifedipine group. Even after adjusting for covariates including antenatal steroid use, gestational age at admission, and pre-pregnancy body mass index, there was an increased risk of high maternal mean FBG (≥ 95 mg/dL) and PPG2 (≥ 120 mg/dL) levels in the atosiban and ritodrine group than in nifedipine group. The atosiban and ritodrine groups are also at increased risk of neonatal hypoglycemia (< 47 mg/dL) compared to the nifedipine group with the odds ratio of 4.58 and 4.67, respectively (P < 0.05). CONCLUSION: There is an increased risk of maternal hyperglycemia and neonatal hypoglycemia in women with GDM using atosiban and ritodrine tocolytics for preterm labor compared to those using nifedipine.

Effects of atosiban on clinical outcome in frozen-thawed embryo transfer: a propensity score matching study.

PURPOSE: To evaluate the effects of atosiban on clinical outcomes in patients undergoing frozen-thawed embryo transfer. METHODS: The clinical data of 1093 infertile patients who underwent frozen-thawed embryo transfer in our center from January 2019 to December 2020 were retrospectively analyzed (control, 418; atosiban, 675). Propensity score matching (PSM) analysis identified 400 matched pairs of patients. The implantation rate, clinical pregnancy rate, live birth rate, biochemical pregnancy rate, abortion rate, multiple pregnancy rate, and ectopic pregnancy rate between the two groups were compared. RESULTS: Before PSM, patients differed by infertility factors, number of transferred embryos, and endometrial preparation protocol (P < 0.05). After PSM, characteristics were similar in corresponding patients of the atosiban and control groups. After propensity score matching, we found that there was no significant difference in the implantation rate, clinical pregnancy rate, live birth rate, biochemical pregnancy rate, abortion rate, multiple pregnancy rate, and ectopic pregnancy rate in atosiban and control group (P > 0.05). CONCLUSION: Atosiban did not improve the clinical outcomes of infertile patients with frozen-thawed embryo transfer.

Arrest of mouse preterm labor until term delivery by combination therapy with atosiban and mundulone, a natural product with tocolytic efficacy.

There is a lack of FDA-approved tocolytics for the management of preterm labor (PL). In prior drug discovery efforts, we identified mundulone and mundulone acetate (MA) as inhibitors of in vitro intracellular Ca2+-regulated myometrial contractility. In this study, we probed the tocolytic potential of these compounds using human myometrial samples and a mouse model of preterm birth. In a phenotypic assay, mundulone displayed greater efficacy, while MA showed greater potency and uterine-selectivity in the inhibition of intracellular-Ca2+ mobilization. Cell viability assays revealed that MA was significantly less cytotoxic. Organ bath and vessel myography studies showed that only mundulone exerted inhibition of myometrial contractions and that neither compounds affected vasoreactivity of ductus arteriosus. A high-throughput combination screen identified that mundulone exhibits synergism with two clinical-tocolytics (atosiban and nifedipine), and MA displayed synergistic efficacy with nifedipine. Of these combinations, mundulone+atosiban demonstrated a significant improvement in the in vitro therapeutic index compared to mundulone alone. The ex vivo and in vivo synergism of mundulone+atosiban was substantiated, yielding greater tocolytic efficacy and potency on myometrial tissue and reduced preterm birth rates in a mouse model of PL compared to each single agent. Treatment with mundulone after mifepristone administration dose-dependently delayed the timing of delivery. Importantly, mundulone+atosiban permitted long-term management of PL, allowing 71% dams to deliver viable pups at term (>day 19, 4-5 days post-mifepristone exposure) without visible maternal and fetal consequences. Collectively, these studies provide a strong foundation for the development of mundulone as a single or combination tocolytic for management of PL.

A randomized double blind comparison of atosiban in patients with recurrent implantation failure undergoing IVF treatment.

BACKGROUND: Patients with recurrent implantation failure (RIF) may have more uterine contractions. Several observational studies suggested that atosiban administration around embryo transfer resulted in higher pregnancy rates in RIF patients. This study aimed to evaluate the effect of atosiban given before fresh embryo transfer on pregnancy outcomes of women with RIF. METHODS: A prospective, randomized, double-blind controlled clinical trial was performed in IVF center of Shanghai First Maternity and Infant Hospital. According to a computer-generated randomization list, 194 infertile women with RIF received fresh embryo transfer between July 2017 and December 2019 were randomly allocated into the atosiban (n = 97) and the placebo (n = 97) groups. Women in the treatment group received atosiban intravenously about 30 min before embryo transfer with a bolus dose of 6.75 mg over one minute. Those in the placebo group received only normal saline infusion for the same duration. RESULTS: There was no significant difference in the live birth rate between the atosiban and placebo groups (42.3% vs 35.1%, P = 0.302, RR = 1.206 (0.844-1.723)). No significant differences were found between the two groups in the positive pregnancy test, clinical pregnancy, ongoing pregnancy, miscarriage, multiple pregnancy, ectopic pregnancy and implantation rates. Similar results were found when stratified by the number of embryos previously transferred, number of previous failed embryo transfers, frequency of endometrial peristalsis on embryo transfer day (≥ 3 waves/min) or serum estradiol (E2) on the day of hCG above the median level. And, there was no correlation between the serum E2 level on the day of hCG and the frequency of endometrial peristalsis on embryo transfer day. The frequency of endometrial peristalsis on embryo transfer day, total FSH/HMG dosage and duration were the significant factors which independently predicted the likelihood of a live birth. CONCLUSIONS: These results suggested that atosiban treatment before fresh embryo transfer might not improve the live birth rate in RIF patients. TRIAL REGISTRATION: The study had been approved by the Institutional Review Board of the hospital (2017 ethics No.43) and was registered under Clinicaltrials.gov with an identifier NCT02893722.

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.

Mechanism of Oxytocin-Induced Contraction in Rat Gastric Circular Smooth Muscle.

Oxytocin produces an excitatory effect on gastric muscle through the activation of receptors present on stomach smooth muscle cells. However, the intracellular mechanisms that mediate oxytocin excitatory effects are still largely unknown. Therefore, we aimed to investigate the signaling pathways involved in oxytocin-induced contractions in gastric smooth muscle, shedding light on phospholipase C (PLC)-ß1 signaling and its downstream molecules, including inositol 1,4,5- trisphosphate (IP3) and myosin light chain kinase (MLCK). The contractions of gastric smooth muscle from male rats were measured in an organ bath set up in response to exogenous oxytocin 10-7 M, in the presence and absence of inhibitors of the indicated signaling molecules. Oxytocin (10-9-10-5 M) induced dose-dependent stomach smooth muscle contraction. Pre-incubation with atosiban, an oxytocin receptor inhibitor, abolished the oxytocin-induced contraction. Moreover, PLC ß1 inhibitor (U73122) and IP3 inhibitor Xestospongin C inhibited oxytocin-induced muscle contraction to various degrees. Verapamil, a calcium channel blocker, inhibited oxytocin-induced contraction, and pre-incubation of the strips, with both verapamil and Xestospongin C, further inhibited the excitatory effect of oxytocin. Chelation of intracellular calcium with BAPT-AM (1,2-bis-(o-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid) significantly inhibited the effect of oxytocin on muscle contraction. Finally, pre-incubation of the strips with the Ca2+/calmodulin-dependent protein kinase selective inhibitor STO-609 significantly inhibited the contraction induced by oxytocin. These results suggest that oxytocin directly stimulates its cell surface receptor to activate PLC ß1, which in turn liberates IP3, which eventually elevates intracellular calcium, the prerequisite for smooth muscle contraction.

Production of Atosiban's Key Intermediate Pentapeptide: Synthetic Approaches to the Development of a Peptide Synthesis with Less Racemization and Simplifier Purification Process.

The key intermediate NH2-Ile-Thr(Bzl)-Asn-Cys(Bzl)-Pro-COOH of Atosiban was prepared from N-Boc-S-Bzl-cysteine by the stepwise lengthening of the chain according to the repetitive N,O-bis(trimethylsilyl)acetamide/N-hydroxysuccinimide ester (BSA/NHS) strategy. This synthetic route required no chromatography purification and can be readily performed, yielding a highly pure pentapeptide compound.

Is oxytocin receptor antagonist administration around embryo transfer associated with IVF treatment success? A systematic review and meta-analysis.

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.

Administration of oxytocin antagonist at the same time as using a Foley catheter with cotton swab before embryo transfer for cervical stenosis.

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.

Report from "International Workshop for Junior Fellows 2: Tocolytic treatment for prevention of preterm birth" at the 73rd Annual Congress of the Japan Society of Obstetrics and Gynecology.

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.

Comparison of frozen-thawed embryo transfer protocols in patients with previous cycle cancellation due to uterine peristalsis: a pilot study

Background/aim: To investigate the optimal protocol for frozen-thawed embryo transfer (FET) cycles in patients who previously had a cycle cancellation due to uterine peristalsis (UP). Materials and methods: Thirty-four patients with previous embryo transfer (ET) cancellation due to UP during artificial cycle (AC) were included retrospectively. In the proceeding cycle, endometrium was prepared with AC (n: 23) in AC-FET group or with stimulated cycle that contains letrozole (L) (n: 11) in L-FET group. Intravenous bolus dose of 6.75 mg atosiban (Tractocile; Ferring Pharmaceuticals, Switzerland) injection was performed to all patients of AC-FET group due to UP ≥ 4/min on the planned ET day of proceeding cycle. Atosiban was not used in L-FET group. Primary outcome was live birth rate (LBR) per ET. Secondary outcomes were clinical pregnancy rate (CPR) per ET, implantation rate (IR), cycle cancellation rate. Results: The baseline characteristics such as age, body mass index, antral follicle count, duration of infertility, and the number of prior in vitro fertilization attempts of each group were similar. The IR, CPR per ET, LBR per ET, CPR per cycle and LBR per cycle were significantly higher; cycle cancellation rates were significantly lower in L-FET group as compared to the AC-FET group. Conclusion: Endometrial preparation with letrozole significantly improves CPR and LBR in FET cycles of patients with previous cycle cancellations due to UP.

Regular moderate exercise alleviates gastric oxidative damage in rats via the contribution of oxytocin receptors.

KEY POINTS: A moderate level of exercise has beneficial effects for the prevention of gastric ulcers. Although regular aerobic exercise was shown to elevate serum oxytocin levels and exogenously administered oxytocin exerts an anti-ulcer activity, the role of endogenous oxytocin in the gastroprotective effects of exercise has not yet been elucidated. We showed that increased anxiety and oxidative gastric damage induced by gastric ulcers were reversed in pre-exercised rats, while reduced hypothalamic oxytocin expression and decreased myenteric oxytocin receptor expression due to gastric ulcers were abolished by exercise. We also reported that the blockade of oxytocin receptors exaggerated gastric damage in exercised rats with ulcers. Our data establish that endogenous oxytocin is the key mediator in the beneficial effects of regular physical activity in alleviating gastric injury. ABSTRACT: Exercise increases serum oxytocin levels and exogenous oxytocin exerts an anti-ulcer activity; but the role of oxytocin in the protective effects of exercise against gastric ulcers has not yet been evaluated. This study was designed to investigate the impact of regular swimming exercise on oxidative gastric injury, and the role of oxytocin receptor activity in the anxiolytic and anti-inflammatory actions of exercise. Adult Wistar albino rats of both sexes performed swimming exercise (30 min/day, 5 days) or stayed sedentary. At the end of the 6-week exercise/sedentary protocol, rats were injected intraperitoneally with atosiban (0.1 mg/kg/day) or saline for 4 days. On the 5th day, under anaesthesia, acetic acid (ulcer) or saline (sham) was applied onto the gastric serosa and the treatments were continued. On the 9th day, anxiety levels were determined; gastric blood flow was measured, and blood, gastric and brain tissues were obtained. Induction of ulcers in sedentary rats increased anxiety and serum corticosterone levels; but reduced gastric blood flow and resulted in apoptosis and oxidative gastric damage with increased cytokine expressions. However, when ulcers were induced in pre-exercised rats, behavioural and biochemical alterations due to gastric damage were reversed. The inhibition of oxytocin receptors by atosiban exaggerated pro-inflammatory cytokine expressions and gastric lipid peroxidation in the stomachs of exercised rats with ulcers. When rats had regularly exercised prior to ulcer induction, reductions in the immunolabelling of hypothalamic oxytocin and myenteric oxytocin receptors were abolished, suggesting that exercise-induced alleviation of gastric injury may involve the reversal of down-regulated oxytocinergic activity.

In vitro contractile responses of human detrusor smooth muscle to oxytocin: does it really have effect?

BACKGROUND AND OBJECTIVES: The aim of this study was to investigate the contractile effects of oxytocin (OT) in human detrusor muscle in in vitro conditions. MATERIAL AND METHODS: Human detrusor muscle samples were obtained from seven patients that undergone radical cystectomy. Four female Wistar rats' uterine samples were used as control. Contractile responses were tested of carbachol in organ bath. Cumulative concentration response curves were constructed to OT and then the strips were incubated with atosiban (OT antagonist) and a second concentration response curve to OT were constructed. RESULTS: Carbachol, contracted all human strips for the functionality test whereas OT in any concentrations did not produce significant contraction on all human strips. In only one bladder strip and in a very high concentration slight contraction was recorded. Moreover no contractile response was recorded in any OT concentrations in the presence of atosiban. The rat uterine strips responded to OT in a dose dependent manner. Atosiban, the OT receptor antagonist diminished totally those contractile responses. CONCLUSION: It is been demonstrated here that there is no contractile response to OT in human detrusor muscle. These findings should be supported by further investigations determining the presence of the OT receptor in human detrusor.

Effects of tocolysis with nifedipine or atosiban on child outcome: follow-up of the APOSTEL III trial.

OBJECTIVE: To compare the long-term effects of tocolysis with nifedipine or atosiban on child outcome at age 2.5-5.5 years. DESIGN: The APOSTEL III trial was a multicentre randomised controlled trial that compared tocolysis with nifedipine or atosiban in 503 women with threatened preterm birth. Neonatal outcomes did not differ between both treatment arms, except for a higher incidence of intubation in the atosiban group. METHODS: Parents were asked to complete four questionnaires regarding neurodevelopment, executive function, behaviour problems and general health. MAIN OUTCOME MEASURES: The main long-term outcome measure was a composite of abnormal development at the age of 2.5-5.5 years. RESULTS: Of the 426 women eligible for follow-up, 196 (46%) parents returned the questionnaires for 115 children in the nifedipine group and 110 children in the atosiban group. Abnormal development occurred in 32 children (30%) in the nifedipine group and in 38 children (38%) in the atosiban group (OR 0.74, 95% CI 0.41-1.34). The separate outcomes for neurodevelopment, executive function, behaviour, and general health showed no significant differences between the groups. Sensitivity analysis for all children of the APOSTEL III trial, including a comparison of deceased children, resulted in a higher rate of healthy survival in the nifedipine group (64 versus 54%), but there was no significant difference in the overall mortality rate (5.4 versus 2.7%). There were no significant subgroup effects. CONCLUSION: Outcomes on broad child neurodevelopment, executive function, behaviour and general health were comparable in both groups. Neither nifedipine nor atosiban can be considered as the preferred treatment for women with threatened preterm birth. TWEETABLE ABSTRACT: Nifedipine- and atosiban-exposed children had comparable long-term outcomes, including neurodevelopment, executive function and behaviour.

Copulation-induced antinociception in female rats is blocked by atosiban, an oxytocin receptor antagonist.

AIMS: We hypothesized that copulation-induced temporary anti-nociception in female rats is mediated by the activation of central and/or peripheral oxytocin receptors. To test this hypothesis, we assessed the effects of intraperitoneal (ip), intrathecal (it), and intra-cerebroventricular (icv) administration of an oxytocin receptor antagonist (atosiban), on copulation-induced temporary anti-nociception in estrous rats. MAIN METHODS: The treatment groups were ovariectomized rats pre-treated subcutaneously (sc) with 10 µg of estradiol benzoate (EB) followed 24 h later by an sc injection of 5 µg EB, and 4 h later, by an sc injection of 2 mg progesterone (P4). Rats were then administered saline vehicle (ip, it, or icv: control groups) or atosiban (500 µg/kg ip; 500 ng it; or 500 ng icv: experimental groups). Thirty minutes after drug or saline administration, their sexual behavior was tested by pairing with a sexually-experienced male rat. Brief pulse trains of 50 Hz, 300 ms duration, supra-threshold tail electrical shocks (STS) were delivered before and during copulatory activity i.e., while the female was receiving mounts, intromissions, or ejaculations, and we recorded whether vocalization occurred in response to each STS. KEY FINDINGS: Replicating our previous findings, the vocalization response to STS in control rats was significantly attenuated during intromissions and ejaculations, compared to their baseline (pre-mating) response, indicative of anti-nociception. By contrast, rats pre-treated with atosiban (each route of administration) failed to show an attenuation of the vocalization response to shock. SIGNIFICANCE: These findings provide evidence that the temporary anti-nociceptive effect of copulation in female rats is mediated by copulation-induced release of endogenous oxytocin in brain, spinal cord and periphery.

Cost effectiveness of nifedipine compared with atosiban in the treatment of threatened preterm birth (APOSTEL III trial).

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: €34,897 versus €43,376, mean difference (MD) -€8479 [95% confidence interval (CI) -€14,327 to -€2016)]; multiple pregnancies: €90,248 versus €102,292, MD -€12,044 (95% CI -€21,607 to € -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.

The use of atosiban prolongs pregnancy in patients treated with fetoscopic endotracheal occlusion (FETO).

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 (ß = 0.375; P < 0.013). 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.

Bryophyllum pinnatum enhances the inhibitory effect of atosiban and nifedipine on human myometrial contractility: an in vitro study.

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 < 0.001, respectively). In the case of AUC, BPJ plus atosiban promoted a decrease to 48.8 ± 6.3% of initial, whereas BPJ and atosiban alone lowered it to 70.9 ± 4.7% and to 80.9 ± 4.1% of initial, respectively. Also in the case of AUC, BPJ plus nifedipine promoted a decrease to 39.9 ± 4.6% of initial, at the same time that BPJ and nifedipine alone lowered it to 78.9 ± 3.8% and 71.0 ± 3.4% of initial. Amplitude data supported those AUC data. The inhibitory effects of BPJ plus atosiban and of BPJ plus nifedipine on contractions strength were concentration-dependent. None of the test substances, alone or in combination, decreased myometrial cell viability. 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.