An oxytocin receptor antagonist (atosiban) in the treatment of preterm labor: a randomized, double-blind, placebo-controlled trial with tocolytic rescue

The oxytocin antagonist cligosiban reduces human prostate contractility: Implications for the treatment of benign prostatic hyperplasia

BACKGROUND AND PURPOSE

With increasing life expectancy, benign prostatic hyperplasia (BPH) consequently affects more ageing men, illustrating the urgent need for advancements in BPH therapy. One emerging possibility may be the use of oxytocin antagonists to relax smooth muscle cells in the prostate, similar to the currently used (although often associated with side effects) α1-adrenoceptor blockers.

EXPERIMENTAL APPROACH

For the first time we used live-imaging, combined with a novel image analysis method, to investigate the multidirectional contractions of the human prostate and determine their changes in response to oxytocin and the oxytocin antagonists atosiban and cligosiban. Human prostate samples were obtained and compared from patients undergoing prostatectomy due to prostate cancer as well as from patients with transurethral resection of prostate tissue due to severe BPH.

KEY RESULTS

The two cohorts of tissue samples showed spontaneous multidirectional contractions, which significantly increased after the addition of oxytocin. Different to atosiban, which showed ambiguous effects of short duration, only long-acting cligosiban reliably prevented, as well as counteracted, any contractile oxytocin effect. Furthermore, cligosiban visibly reduced not only oxytocin-induced contractions, but also showed intrinsic activity to relax prostatic tissue.

CONCLUSION AND IMPLICATIONS

Thus, the oxytocin antagonist cligosiban could be an interesting candidate in the search for novel BPH treatment options.

A historical narrative review through the field of tocolysis in threatened preterm birth

Preterm birth presents a significant challenge in clinical obstetrics, requiring effective strategies to reduce associated mortality and morbidity risks. Tocolytic drugs, aimed at inhibiting uterine contractions, are a key aspect of addressing this challenge. Despite extensive research over many years, determining the most effective tocolytic agents remains a complex task, prompting better understanding of the underlying mechanisms of spontaneous preterm birth and recording meaningful outcome measures. This paper provides a comprehensive review of various obsolete and current tocolytic drug regimens that were instituted over the past century, examining both historical contexts and contemporary challenges in their development and adoption. The examination of historical debates and advancements highlights the complexity of introducing new therapies. While the search for effective tocolytics continues, questions arise regarding their actual benefits in obstetric care and the necessity for ongoing exploration. The presence of methodological limitations in current research emphasizes the importance of well-designed randomized controlled trials with robust endpoints and extended follow-up periods.In response to these complexities, the consideration of shifting towards prevention strategies aimed at addressing the root causes of preterm labor becomes more and more evident. This potential shift may offer a more effective approach than relying solely on tocolytics to delay labor initiation.Ultimately, effectively managing threatened preterm birth necessitates ongoing investigation, innovation, and a willingness to reassess strategies in pursuit of optimal outcomes for mothers, neonates, and long-term child health.

The physiology and pharmacology of oxytocin in labor and in the peripartum period

Oxytocin is a reproductive hormone implicated in the process of parturition and widely used during labor. Oxytocin is produced within the supraoptic nucleus and paraventricular nucleus of the hypothalamus and released from the posterior pituitary lobe into the circulation. Oxytocin is released in pulses with increasing frequency and amplitude in the first and second stages of labor, with a few pulses released in the third stage of labor. During labor, the fetus exerts pressure on the cervix of the uterus, which activates a feedforward reflex-the Ferguson reflex-which releases oxytocin. When myometrial contractions activate sympathetic nerves, it decreases oxytocin release. When oxytocin binds to specific myometrial oxytocin receptors, it induces myometrial contractions. High levels of circulating estrogen at term make the receptors more sensitive. In addition, oxytocin stimulates prostaglandin synthesis and release in the decidua and chorioamniotic membranes by activating a specific type of oxytocin receptor. Prostaglandins contribute to cervical ripening and uterine contractility in labor. The oxytocin system in the brain has been implicated in decreasing maternal levels of fear, pain, and stress, and oxytocin release and function during labor are stimulated by a social support. Moreover, studies suggest, but have not yet proven, that labor may be associated with long-term, behavioral and physiological adaptations in the mother and infant, possibly involving epigenetic modulation of oxytocin production and release and the oxytocin receptor. In addition, infusions of synthetic oxytocin are used to induce and augment labor. Oxytocin may be administered according to different dose regimens at increasing rates from 1 to 3 mIU/min to a maximal rate of 36 mIU/min at 15- to 40-minute intervals. The total amount of synthetic oxytocin given during labor can be 5 to 10 IU, but lower and higher amounts of oxytocin may also be given. High-dose infusions of oxytocin may shorten the duration of labor by up to 2 hours compared with no infusion of oxytocin; however, it does not lower the frequency of cesarean delivery. When synthetic oxytocin is administered, the plasma concentration of oxytocin increases in a dose-dependent way: at infusion rates of 20 to 30 mIU/min, plasma oxytocin concentration increases approximately 2- to 3-fold above the basal level. Synthetic oxytocin administered at recommended dose levels is not likely to cross the placenta or maternal blood-brain barrier. Synthetic oxytocin should be administered with caution as high levels may induce tachystole and uterine overstimulation, with potentially negative consequences for the fetus and possibly the mother. Of note, 5 to 10 IU of synthetic oxytocin is often routinely given as an intravenous or intramuscular bolus administration after delivery to induce uterine contractility, which, in turn, induces uterine separation of the placenta and prevents postpartum hemorrhage. Furthermore, it promotes the expulsion of the placenta.

Expedient and divergent synthesis of unnatural peptides through cobalt-catalyzed diastereoselective umpolung hydrogenation

The development of a reliable method for asymmetric synthesis of unnatural peptides is highly desirable and particularly challenging. In this study, we present a versatile and efficient approach that uses cobalt-catalyzed diastereoselective umpolung hydrogenation to access noncanonical aryl alanine peptides. This protocol demonstrates good tolerance toward various functional groups, amino acid sequences, and peptide lengths. Moreover, the versatility of this reaction is illustrated by its successful application in the late-stage functionalization and formal synthesis of various representative chiral natural products and pharmaceutical scaffolds. This strategy eliminates the need for synthesizing chiral noncanonical aryl alanines before peptide formation, and the hydrogenation reaction does not result in racemization or epimerization. The underlying mechanism was extensively explored through deuterium labeling, control experiments, HRMS identification, and UV-Vis spectroscopy, which supported a reasonable CoI/CoIII catalytic cycle. Notably, acetic acid and methanol serve as safe and cost-effective hydrogen sources, while indium powder acts as the terminal electron source.

Addressing a broken drug pipeline for preterm birth: why early preterm birth is an orphan disease

Preterm birth remains one of the most urgent unresolved medical problems in obstetrics, yet only 2 therapeutics for preventing preterm birth have ever been approved by the United States Food and Drug Administration, and neither remains on the market. The recent withdrawal of 17-hydroxyprogesterone caproate (17-OHPC, Makena) marks a new but familiar era for obstetrics with no Food and Drug Administration-approved pharmaceuticals to address preterm birth. The lack of pharmaceuticals reflects a broad and ineffective pipeline hindered by extensive regulatory hurdles, soaring costs of performing drug research, and concerns regarding adverse effects among a particularly vulnerable population. The pharmaceutical industry has historically limited investments in research for diseases with similarly small markets, such as cystic fibrosis, given their rarity and diminished projected financial return. The Orphan Drug Act, however, incentivizes drug development for "orphan diseases", defined as affecting <200,000 people in the United States annually. Although the total number of preterm births in the United States exceeds this threshold annually, the early subset of preterm birth (<34 weeks' gestation) would qualify, which is predominantly caused by inflammation and infection. The scientific rationale for classifying preterm birth into early and late subsets is strong given that their etiologies differ, and therapeutics that may be efficacious for one subset may not work for the other. For example, antiinflammatory therapeutics would be expected to be highly effective for early but not late preterm birth. A robust therapeutic pipeline of antiinflammatory drugs already exists, which could be used to target spontaneous early preterm birth, in combination with antibiotics shown to sterilize the amniotic cavity. New applications for therapeutics targeting spontaneous early preterm birth could categorize as orphan disease drugs, which could revitalize the preterm birth therapeutic pipeline. Herein, we describe why drugs targeting early preterm birth should qualify for orphan status, which may increase pharmaceutical interest for this vitally important obstetrical condition.

Effectiveness of atosiban in women with previous single implantation failure undergoing frozen-thawed blastocyst transfer: study protocol for a randomised controlled trial

BACKGROUND

Uterine contractions may interfere with embryo implantation in assisted reproductive technology. To reduce these contractions and improve success rates, the oxytocin antagonist atosiban has been suggested for administration during embryo transfer. The aim of this study is to evaluate the effectiveness of atosiban in increasing live birth rates among women who have previously experienced a single implantation failure and are scheduled for single blastocyst transfer.

METHODS AND ANALYSIS

We conduct a single-centre randomised controlled study comparing atosiban and placebo in women undergoing a single blastocyst transfer with a previous failed blastocyst transfer. Women with endocrine or systemic illnesses, recurrent miscarriages, uterine malformations or fibroids, untreated hydrosalpinx, endometriosis (stage III or IV) or uterine fibroids, as well as women undergoing preimplantation genetic testing, are ineligible. The primary outcome is live birth resulting from the frozen-thawed embryo transfer. Secondary outcomes include biochemical/clinical pregnancy, miscarriage, ectopic pregnancy, multiple pregnancies as well as maternal and perinatal outcomes. We plan to recruit 1100 women (550 women per group). This will allow us to demonstrate or refute an increase in live birth rate from 40% to 50%. Data analysis will follow the intention-to-treat principle. We will measure patterns of uterine peristalsis which will allow subgroup analysis for women with or without uterine peristalsis.

ETHICS AND DISSEMINATION

This study has been approved by the Institutional Review Board of Northwest Women's and Children's Hospital (No. SZ2019001). Written informed consent will be obtained from each participant before randomisation. The results of the trial will be presented at scientific meetings and reported in publications.

TRIAL REGISTRATION NUMBER

ChiCTR1900022333.

A multicenter, retrospective comparison of pregnancy outcomes between groups of preterm labor nulliparous mothers treated with atosiban vs. ritodrine in singleton and multiple pregnancies

OBJECTIVE

To evaluate the safety and efficacy of atosiban and ritodrine in pregnant women who were hospitalized for threatened preterm labor (TPL).

MATERIALS AND METHODS

Diagnosis records of preterm labor and subsequent pregnancy-related records and medical records of newborns were extracted from the Clinical Data Warehouse of the Catholic Medical Center's affiliated hospital. Since 2009, cases of preterm labor diagnosed before 34 weeks of pregnancy for first-time mothers who delivered at any one of three hospitals and who received drug treatment for more than 2 days to delay delivery were included in the dataset. Based on characteristics of Korea's national health insurance system, the drug treatment after diagnosis of preterm labor could be classified into cases using only ritodrine (571 women), cases using only atosiban (244 women), and cases where ritodrine treatment was started and then changed to atosiban (275 women). Demographic factors, obstetric outcomes, neonatal outcomes of the two groups were analyzed.

RESULTS

The duration and maintenance of pregnancy were found to be similar between the two groups, although the initial cervical length was significantly shorter in the atosiban cohort (AC). Only in multifetal pregnancies, the maintenance of pregnancy was significantly longer in the AC. The total duration of pregnancy did not show any significant difference between the two groups regardless of singleton or multiple pregnancy. However, the distribution graph showed non-responders in the ritodrine cohort (RC). Our study showed a difference in neonatal birth weight of singleton between the two groups. The length of hospitalization and the NICU admission rate were also significantly higher in the RC for singleton. Although not significant, the proportion of numbers with an Apgar score less than 7 was higher in the RC. Neonatal death was more common in the RG (8 cases in AC and 18 cases in RC).

CONCLUSIONS

Using atosiban for TPL is more effective than using ritodrine for maintaining pregnancy in the case of a multifetal pregnancy. In singleton pregnancies, neonatal outcomes of the atosiban group were superior to those of the ritodrine group. There seems to be a non-responder group when using ritodrine for TPL. Further studies are needed to determine causes of non-responders of ritodrine and effects of ritodrine on the fetus.

Atosiban-induced acute pulmonary edema: A rare but severe complication of tocolysis

Background

Atosiban is commonly used to delay premature labor in pregnant women and is thought to have few side effects.

Objectives

To report a case of acute pulmonary edema (APE) following administration of atosiban and conduct a systematic review to identify common characteristics and risk factors of atosiban-associated APE.

Methods

Searches were performed in Pubmed, Embase, and Web of Science using the keyword "Atosiban" combined with the terms "Pulmonary edema" or "Dyspnea" or "Hypoxia" on 9th July 2022. Only case reports of atosiban-associated APE were included without language restrictions. Data were extracted from the reports, and median, range, and percentages were calculated as applicable. The risk of bias was assessed using the Joanna Briggs Institute critical appraisal checklist for case reports.

Results

Seven cases of atosiban-associated APE were included in the systematic review, including our case. APE occurred at a median gestational age of 32 + 6 weeks. Most patients were nulliparous (6/7, 85.7%) and were in multiple pregnancies (5/7, 71.4%). All patients were prescribed antenatal corticosteroids and tocolytics, with three (42.9%) receiving only atosiban and four (57.1%) receiving atosiban and other tocolytics. The median interval from starting atosiban administration to APE onset was about 40 h, and three patients (42.9%) showed symptoms 2-10 h after the end of atosiban treatment. Radiographic examinations (chest X-ray and/or computer tomography scan) confirmed APE in all patients and pleural effusion in four patients (57.1%). Five patients (71.4%) underwent emergency cesarean section, one patient (14.3%) with twin pregnancy had vaginal delivery with the help of suction cup and forceps, and another patient (14.3%) continued the pregnancy. All patients recovered well after administration of oxygen, diuresis, and other supportive therapy.

Conclusion

Atosiban may cause acute pulmonary edema in patients with underlying risk factors. This complication remains rare, but caution during tocolytic treatment using atosiban is recommended.

Tocolytic Therapy Inhibiting Preterm Birth in High-Risk Populations: A Systematic Review and Meta-Analysis

This systematic review aimed to identify the benefits and possible harms of tocolytic therapy for preterm labour management in the context of pregnant women with extremely preterm birth, multiple gestations, or growth-restricted foetuses. A comprehensive search using MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, CINAHL, and the WHO Global Index Medicus databases was conducted from 10 to 15 July 2021. We included randomized controlled trials and non-randomized studies that assessed the effects of tocolysis compared with placebo or no treatment. We found 744 reports and, finally, nine studies (three randomized controlled trials and six cohort studies) pertaining to women with <28 weeks of gestation were included. No eligible studies were identified among women with a multiple pregnancy or a growth-restricted foetus. A meta-analysis of the trial data showed that there were no clear differences in perinatal death nor for a delay in birth. Non-randomized evidence showed that tocolysis delayed birth by 7 days, though there was no clear difference for preterm birth. In summary, it remains unclear whether tocolytic therapy for inhibiting preterm labour is beneficial for these subgroups of women and their newborns. Further well-designed randomized controlled trials and observational studies are needed to address the lack of evidence regarding tocolytic agents in these populations.

Tocolytics for delaying preterm birth: a network meta-analysis (0924)

BACKGROUND

Preterm birth is the leading cause of death in newborns and children. Tocolytic drugs aim to delay preterm birth by suppressing uterine contractions to allow time for administration of corticosteroids for fetal lung maturation, magnesium sulphate for neuroprotection, and transport to a facility with appropriate neonatal care facilities. However, there is still uncertainty about their effectiveness and safety.

OBJECTIVES

To estimate relative effectiveness and safety profiles for different classes of tocolytic drugs for delaying preterm birth, and provide rankings of the available drugs.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov (21 April 2021) and reference lists of retrieved studies.

SELECTION CRITERIA

We included all randomised controlled trials assessing effectiveness or adverse effects of tocolytic drugs for delaying preterm birth. We excluded quasi- and non-randomised trials. We evaluated all studies against predefined criteria to judge their trustworthiness.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed the trials for inclusion and risk of bias, and extracted data. We performed pairwise and network meta-analyses, to determine the relative effects and rankings of all available tocolytics. We used GRADE to rate the certainty of the network meta-analysis effect estimates for each tocolytic versus placebo or no treatment.

MAIN RESULTS

This network meta-analysis includes 122 trials (13,697 women) involving six tocolytic classes, combinations of tocolytics, and placebo or no treatment. Most trials included women with threatened preterm birth, singleton pregnancy, from 24 to 34 weeks of gestation. We judged 25 (20%) studies to be at low risk of bias. Overall, certainty in the evidence varied. Relative effects from network meta-analysis suggested that all tocolytics are probably effective in delaying preterm birth compared with placebo or no tocolytic treatment. Betamimetics are possibly effective in delaying preterm birth by 48 hours (risk ratio (RR) 1.12, 95% confidence interval (CI) 1.05 to 1.20; low-certainty evidence), and 7 days (RR 1.14, 95% CI 1.03 to 1.25; low-certainty evidence). COX inhibitors are possibly effective in delaying preterm birth by 48 hours (RR 1.11, 95% CI 1.01 to 1.23; low-certainty evidence). Calcium channel blockers are possibly effective in delaying preterm birth by 48 hours (RR 1.16, 95% CI 1.07 to 1.24; low-certainty evidence), probably effective in delaying preterm birth by 7 days (RR 1.15, 95% CI 1.04 to 1.27; moderate-certainty evidence), and prolong pregnancy by 5 days (0.1 more to 9.2 more; high-certainty evidence). Magnesium sulphate is probably effective in delaying preterm birth by 48 hours (RR 1.12, 95% CI 1.02 to 1.23; moderate-certainty evidence). Oxytocin receptor antagonists are probably effective in delaying preterm birth by 48 hours (RR 1.13, 95% CI 1.05 to 1.22; moderate-certainty evidence), are effective in delaying preterm birth by 7 days (RR 1.18, 95% CI 1.07 to 1.30; high-certainty evidence), and possibly prolong pregnancy by 10 days (95% CI 2.3 more to 16.7 more). Nitric oxide donors are probably effective in delaying preterm birth by 48 hours (RR 1.17, 95% CI 1.05 to 1.31; moderate-certainty evidence), and 7 days (RR 1.18, 95% CI 1.02 to 1.37; moderate-certainty evidence). Combinations of tocolytics are probably effective in delaying preterm birth by 48 hours (RR 1.17, 95% CI 1.07 to 1.27; moderate-certainty evidence), and 7 days (RR 1.19, 95% CI 1.05 to 1.34; moderate-certainty evidence). Nitric oxide donors ranked highest for delaying preterm birth by 48 hours and 7 days, and delay in birth (continuous outcome), followed by calcium channel blockers, oxytocin receptor antagonists and combinations of tocolytics. Betamimetics (RR 14.4, 95% CI 6.11 to 34.1; moderate-certainty evidence), calcium channel blockers (RR 2.96, 95% CI 1.23 to 7.11; moderate-certainty evidence), magnesium sulphate (RR 3.90, 95% CI 1.09 to 13.93; moderate-certainty evidence) and combinations of tocolytics (RR 6.87, 95% CI 2.08 to 22.7; low-certainty evidence) are probably more likely to result in cessation of treatment. Calcium channel blockers possibly reduce the risk of neurodevelopmental morbidity (RR 0.51, 95% CI 0.30 to 0.85; low-certainty evidence), and respiratory morbidity (RR 0.68, 95% CI 0.53 to 0.88; low-certainty evidence), and result in fewer neonates with birthweight less than 2000 g (RR 0.49, 95% CI 0.28 to 0.87; low-certainty evidence). Nitric oxide donors possibly result in neonates with higher birthweight (mean difference (MD) 425.53 g more, 95% CI 224.32 more to 626.74 more; low-certainty evidence), fewer neonates with birthweight less than 2500 g (RR 0.40, 95% CI 0.24 to 0.69; low-certainty evidence), and more advanced gestational age (MD 1.35 weeks more, 95% CI 0.37 more to 2.32 more; low-certainty evidence). Combinations of tocolytics possibly result in fewer neonates with birthweight less than 2500 g (RR 0.74, 95% CI 0.59 to 0.93; low-certainty evidence). In terms of maternal adverse effects, betamimetics probably cause dyspnoea (RR 12.09, 95% CI 4.66 to 31.39; moderate-certainty evidence), palpitations (RR 7.39, 95% CI 3.83 to 14.24; moderate-certainty evidence), vomiting (RR 1.91, 95% CI 1.25 to 2.91; moderate-certainty evidence), possibly headache (RR 1.91, 95% CI 1.07 to 3.42; low-certainty evidence) and tachycardia (RR 3.01, 95% CI 1.17 to 7.71; low-certainty evidence) compared with placebo or no treatment. COX inhibitors possibly cause vomiting (RR 2.54, 95% CI 1.18 to 5.48; low-certainty evidence). Calcium channel blockers (RR 2.59, 95% CI 1.39 to 4.83; low-certainty evidence), and nitric oxide donors probably cause headache (RR 4.20, 95% CI 2.13 to 8.25; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Compared with placebo or no tocolytic treatment, all tocolytic drug classes that we assessed (betamimetics, calcium channel blockers, magnesium sulphate, oxytocin receptor antagonists, nitric oxide donors) and their combinations were probably or possibly effective in delaying preterm birth for 48 hours, and 7 days. Tocolytic drugs were associated with a range of adverse effects (from minor to potentially severe) compared with placebo or no tocolytic treatment, although betamimetics and combination tocolytics were more likely to result in cessation of treatment. The effects of tocolytic use on neonatal outcomes such as neonatal and perinatal mortality, and on safety outcomes such as maternal and neonatal infection were uncertain.

Novel oxytocin receptor antagonists for tocolysis: a systematic review and meta-analysis of the available data on the efficacy, safety, and tolerability of retosiban

OBJECTIVE

To assess the efficacy, safety, and tolerability of retosiban-a novel tocolytic unavailable in the US-in the management of preterm labor.

METHODS

We searched ClinicalTrials.Gov, MEDLINE, PubMed, SCOPUS, Web of Science, and the Cochrane Library for relevant clinical trials using the terms "retosiban" and "preterm labor" through 09/2020. We included all published randomized clinical trials (three) that compared retosiban to placebo for preterm labor, excluding conferences, books, reviews, posters, case reports, and animal studies. We analyzed homogeneous data under the fixed-effects model and heterogeneous data under the random-effects model.

RESULTS

We included all randomized clinical trials addressing this topic, which ultimately resulted in three trials with a total of 116 patients. There were no significant differences between retosiban and placebo in births at term (RR = 0.41, p = .02), births ≤7 days from the first study treatment (RR = 0.59, p = .23), or administration of rescue tocolytic (RR = 0.36, p = .07); the maternal adverse events of headache, anemia, constipation, or urinary tract infection (p > .05); or neonatal outcomes of Apgar score at 1 min (p = .88) or 5 min (p = .69), weight (p = .23), head circumference (p = .55), malnutrition (p = .27), hyperbilirubinemia (RR = 0.56, p = .21), jaundice (RR = 1.21, p = .84), respiratory distress (RR = 0.53, p = .49), or tachypnea (RR = 0.40, p = .42).

CONCLUSION

With the limited high quality evidence available, retosiban demonstrates no clear benefit over placebo in the management of preterm labor. Nevertheless, its favorable safety profile, oral bioavailability, and novel mechanism of action and the limited number of studies available for review warrant further analysis.

Landscape of Preterm Birth Therapeutics and a Path Forward

Preterm birth (PTB) remains the leading cause of infant morbidity and mortality. Despite 50 years of research, therapeutic options are limited and many lack clear efficacy. Tocolytic agents are drugs that briefly delay PTB, typically to allow antenatal corticosteroid administration for accelerating fetal lung maturity or to transfer patients to high-level care facilities. Globally, there is an unmet need for better tocolytic agents, particularly in low- and middle-income countries. Although most tocolytics, such as betamimetics and indomethacin, suppress downstream mediators of the parturition pathway, newer therapeutics are being designed to selectively target inflammatory checkpoints with the goal of providing broader and more effective tocolysis. However, the relatively small market for new PTB therapeutics and formidable regulatory hurdles have led to minimal pharmaceutical interest and a stagnant drug pipeline. In this review, we present the current landscape of PTB therapeutics, assessing the history of drug development, mechanisms of action, adverse effects, and the updated literature on drug efficacy. We also review the regulatory hurdles and other obstacles impairing novel tocolytic development. Ultimately, we present possible steps to expedite drug development and meet the growing need for effective preterm birth therapeutics.

Short-Term Outcomes of Atosiban in the Treatment of Preterm Labour at the Sultan Qaboos University Hospital, Muscat, Oman: A tertiary care experience

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 <12 hours. Failure to delay delivery by ≥48 hours was significantly lower among women with normal versus abnormal cervical findings (11.1% versus 25.6%; P = 0.023). Only 9.4% of women experienced minor side-effects. Mean birth weight (2,724.55 versus 1,707.59 g; P <0.001) and Apgar scores at 5 minutes (9.66 versus 8.28; P <0.001) were significantly higher among neonates delivered at ≥48 versus <48 hours post-atosiban, whereas the rate of neonatal respiratory distress syndrome was significantly lower (18.4% versus 81.6%; P <0.001).

Conclusion

Atosiban was highly effective in delaying delivery by ≥48 hours and resulted in few adverse maternal side-effects and neonatal outcomes. To the best of the authors’ knowledge, this is the first study conducted in Oman to evaluate the effectiveness of atosiban in preventing preterm labour.

The determinant role of IL-6 in the establishment of inflammation leading to spontaneous preterm birth

Preterm birth (PTB) and its consequences are a major public health concern as preterm delivery is the main cause of mortality and morbidity at birth. There are many causes of PTB, but inflammation is undeniably associated with the process of premature childbirth and fetal injury. At present, treatments clinically available mostly involve attempt to arrest contractions (tocolytics) but do not directly address upstream maternal inflammation on development of the fetus. One of the possible solutions may lie in the modulation of inflammatory mediators. Of the many pro-inflammatory cytokines involved in the induction of PTB, IL-6 stands out for its pleiotropic effects and its involvement in both acute and chronic inflammation. Here, we provide a detailed review of the effects of IL-6 on the timing of childbirth, its occurrence during PTB and its indissociable roles with associated fetal tissue damage.

Oxytocin in the Male Reproductive Tract; The Therapeutic Potential of Oxytocin-Agonists and-Antagonists

In this review, the role of oxytocin and oxytocin-like agents (acting via the oxytocin receptor and belonging to the oxytocin-family) in the male reproductive tract is considered. Previous research (dating back over 60 years) is revised and connected with recently found aspects of the role oxytocin plays in male reproductive health. The local expression of oxytocin and its receptor in the male reproductive tract of different species is summarized. Colocalization and possible crosstalk to other agents and receptors and their resulting effects are discussed. The role of the newly reported oxytocin focused signaling pathways in the male reproductive tract, other than mediating contractility, is critically examined. The structure and effect of the most promising oxytocin-agonists and -antagonists are reviewed for their potential in treating male disorders with origins in the male reproductive tract such as prostate diseases and ejaculatory disorders.

Safety and Efficacy of Tocolytics for the Treatment of Spontaneous Preterm Labour

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.

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 (β = 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.

Drugs for the Treatment and Prevention of Preterm Labor

Preterm birth can be medically-indicated or spontaneous. Almost half of spontaneous preterm deliveries are preceded by preterm labor. Preterm labor is a clinical diagnosis characterized by regular uterine contractions (painful or painless) with concomitant cervical change. This article discusses the prevention and treatment of spontaneous preterm labor utilizing progesterone and tocolytic agents and provides management recommendations in patients with and without a history of prior spontaneous preterm birth.

In vitro comparison of liposomal drug delivery systems targeting the oxytocin receptor: a potential novel treatment for obstetric complications

Introduction

Targeted intervention to the uterus has great potential for the treatment of obstetric complications (eg, preterm birth, dysfunctional labor, and postpartum hemorrhage) by improving the effectiveness and safety of therapeutic compounds. In particular, targeting the oxytocin receptor (OTR) is a novel approach for drug delivery to the uterus. The aim of this study was to report the complete data set for the pharmaceutical synthesis and in vitro characterization of PEGylated liposomes conjugated with anti-OTR monoclonal antibodies (OTR-Lipo) or atosiban (ATO-Lipo, OTR antagonist).

Methods

OTR-targeted liposomal platforms composed of 1,2-distearoyl-sn-glycero-2-phosphocholine and cholesterol were prepared according to the method of dried lipid film hydration. Ligands were conjugated with the surface of liposomes using optimized methods to maximize conjugation efficiency. The liposomes were characterized for particle size, ligand conjugation, drug encapsulation, liposome stability, specificity of binding, cellular internalization, mechanistic pathway of cellular uptake, and cellular toxicity.

Results

Both OTR-Lipo and ATO-Lipo showed significant and specific binding to OTRs in a concentration-dependent manner compared to all control groups. There was no significant difference in binding values between OTR-Lipo and ATO-Lipo across all concentrations evaluated. In addition, OTR-Lipo (81.61%±7.84%) and ATO-Lipo (85.59%±8.28%) demonstrated significantly increased cellular internalization in comparison with rabbit IgG immunoliposomes (9.14%±1.71%) and conventional liposomes (4.09%±0.78%) at 2.02 mM phospholipid concentration. Cellular association following liposome incubation at 4.05 mM resulted in similar findings. Evaluation of the mechanistic pathway of cellular uptake indicated that they undergo internalization through both clathrin- and caveolin-mediated mechanisms. Furthermore, cellular toxicity studies have shown no significant effect of both liposomal platforms on cell viability.

Conclusion

This study further supports OTRs as a novel pharmaceutical target for drug delivery. OTR-targeted liposomal platforms may provide an effective way to deliver existing therapies directly to myometrial tissue and avoid adverse effects by circumventing non-target tissues.

The Effect of Atosiban on Patients With Difficult Embryo Transfers Undergoing In Vitro Fertilization-Embryo Transfer

The purpose of this study was to evaluate the effect of atosiban on the outcomes of infertile women undergoing in vitro fertilization (IVF) with difficult embryo transfers (ETs). This randomized double-blind study enrolled 204 infertile women with difficult ETs during IVF treatment between June 2014 and June 2018. According to a computer-generated randomization list, participants were randomized into placebo (n = 102) and atosiban (n = 102) groups. In atosiban group, atosiban with a total dose of 37.5 mg was administered. All of the patients underwent IVF-ET using cryopreserved embryos. The clinical pregnancy rate per cycle and implantation rate per transfer (45.1% and 26.5%) in atosiban group were significantly higher than those of placebo group (15.6% and 9.7%, respectively; P < .05). This study showed that administration of atosiban during ET was extraordinarily effective for patients with difficult transfers.

Design of Oxytocin Analogs

The neurohypophyseal hormone oxytocin (OT) and related modulators of the oxytocin receptor (OTR) have been the subject of intensive research for nearly seven decades. Despite having rather poor drug-like properties, OT is used as a treatment for labor induction, postpartum hemorrhage, and lactation support. The potential use of OT in the treatment of central nervous system (CNS)-related diseases has recently renewed interest in the pharmacology of OT. Oxytocin is one of the most extensively studied cyclic peptides and since the elucidation of its structure in 1953 thousands of peptidic OT analogs with antagonistic and agonistic properties have been synthesized and biologically evaluated. Among them are atosiban, a mixed oxytocin receptor (OTR)/vasopressin 1a receptor (V_1aR) antagonist used as a tocolytic agent approved (in certain countries), and carbetocin, a longer acting OTR agonist on the market for the treatment of postpartum hemorrhage. Many other OT analogs with improved pharmacological properties (e.g., barusiban, Antag III) have been identified. These peptides have been tested in clinical trials and/or used as pharmacological tools. In this chapter, the modifications of the OT molecule that led to the discovery of these compounds are reviewed.

Oxidative Stress in Women Treated with Atosiban for Impending Preterm Birth

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.

Predictors of preterm birth

Cervical length (CL) measured by transvaginal ultrasound examination (TVUE) best identifies the risk for preterm birth (PTB). It identifies women at risk who can benefit from corticosteroids or in utero transfer. Early screening improves effectiveness of tocolysis. It reduces iatrogenicity and cost. In preterm premature rupture of membranes (PPROM), CL is devoid of infectious risk and predicts duration of the latency phase but not the risk of perinatal sepsis. Asymptomatic women at risk should be screened at a 2-week interval starting from 16 to 18 weeks, up to 24 weeks. CLs <10th centile are at risk of PTB, especially with decrease in CL after 16 weeks. Repeat ultrasound improves predictive values. Stable CL calls for term delivery. Funneling does not improve predictivity of CL. In twin pregnancies, CL reduces unnecessary interventions. In symptomatic women, fetal fibronectin performs less than CL. Its combination with inconclusive CL has not emerged productive through randomized controlled trials (RCTs), and studies with homogeneous management for preterm labor (PTL) suggest that up to 15% of unjustified hospitalizations and treatment could be avoided.

Short and long-term costs among women experiencing preterm labour or preterm birth: the German experience

Background

Preterm labour and birth (PTL/PTB) is characterised by major health and developmental risks for children, life–changing consequences for their families, and substantial healthcare and economic challenges for wider society. While it is known that PTL/PTB impacts infant healthcare costs in the short and long term in Germany, maternal costs have not been described in detail. The aim of this study was to comprehensively describe costs and resource use among PTL/PTB mothers during pregnancy, at hospitalisation for delivery, and up to three years after delivery—overall and according to gestational age (GA) at delivery.

Methods

This study used data from the Statutory Health Insurance (SHI) sample of the AOK Hessen database in Germany. Mothers aged 12–44 years with deliveries between 2009 and 2013 and > 9 months of medical history prior to delivery were included. PTL/PTB mothers were defined by an International Classification of Diseases, 10th Revision (ICD-10) code for PTL during pregnancy, a diagnosis-related group (DRG) code indicating birthweight < 2500 g, or delivery of an infant < 37 weeks GA. Inpatient and outpatient resource use and total direct medical costs were examined during pregnancy, at delivery hospitalisation, and up to three years post-delivery.

Results

Of all mothers, 2147 (20%) experienced PTL/PTB. During pregnancy, median costs for PTL/PTB mothers were €2130. During delivery hospitalisation, the mean length of stay for all PTL/PTB mothers was 6.0 days, and median costs were €2037. Length of stay and costs declined with increasing GA. Long term, PTL/PTB mothers’ total median costs were €607 in Year 1, €332 in Year 2, and €388 in Year 3 post-delivery. In each year after delivery, median costs appeared to be greater for mothers who delivered at lower GAs.

Conclusion

In this description of costs and resource use among PTL/PTB mothers in Germany throughout the pregnancy and up to three years after delivery, the greatest costs were noted prior to delivery. Costs appeared to decrease with increasing GA, particularly during the delivery hospitalisation and the first year after delivery.

Electronic supplementary material

The online version of this article (10.1186/s12884-018-1912-0) contains supplementary material, which is available to authorized users.

The cost of preterm labor and preterm birth for mothers with uncomplicated pregnancies and their infants in Italy: a retrospective cohort study

BACKGROUND

Preterm labor (PTL)/preterm birth (PTB) impose significant burden on health-care systems. Women with uncomplicated pregnancies at risk of PTL/PTB have not been widely investigated, and published evidence on the costs of these women and their infants in Italy is absent. We aimed to describe women with uncomplicated pregnancies and associated costs for these women and their infants.

METHODS

Data on women aged 12-44 years with uncomplicated pregnancies who delivered between 1 September 2009 and 31 December 2014 with PTL diagnosis alone or PTL and PTB were included from four Italian databases. Costs were examined during pregnancy, delivery, and 3 years after delivery for mothers and infants, overall and by gestational age (GA).

RESULTS

A total of 3058 mothers linked to 3333 infants were included. Costs during pregnancy were €1777. Costs during delivery for PTL/PTB mothers and their infants ranged from €3174 (GA ≥37) to €21007 (GA <28). Combined maternal and infant costs appeared higher for births with lower GAs (<37) in the three-year follow-up.

CONCLUSIONS

In Italy, PTL/PTB mothers with uncomplicated pregnancies with infants at lower GAs appeared to incur higher medical costs compared to mothers with infants at higher GAs in all three time periods, with particularly marked differences found when considering mother and infant combined costs.

Contractility Measurements of Human Uterine Smooth Muscle to Aid Drug Development

Discovery and characterization of novel pharmaceutical compounds or biochemical probes rely on robust and physiologically relevant assay systems. We describe methods to measure ex vivo myometrium contractility. This assay can be used to investigate factors and molecules involved in the modulation of myometrial contraction and to determine their excitatory or inhibitory actions, and hence their therapeutic potential in vivo. Biopsies are obtained from women undergoing cesarean section delivery with informed consent. Fine strips of myometrium are dissected, clipped and attached to a force transducer within 1 mL organ baths superfused with physiological saline solution at 37 °C. Strips develop spontaneous contractions within 2-3 h under set tension and remain stable for many hours (>6 h). Strips can also be stimulated to contract such as by the endogenous hormones, oxytocin and vasopressin, which cause concentration-dependent modulation of contraction frequency, force and duration, to more closely resemble contractions in labor. Hence, the effect of known and novel drug leads can be tested on spontaneous and agonist-induced contractions. This protocol specifically details how this assay can be used to determine the potency of known and novel agents by measuring their effects on various parameters of human myometrial contraction. We use the oxytocin- and V1a receptor antagonists, atosiban and SR49059 as examples of known compounds which inhibit oxytocin- and vasopressin-induced contractions, and demonstrate how this method can be used to complement and validate pharmacological data obtained from cell-based assays to aid drug development. The effects of novel agonists in comparison to oxytocin and vasopressin can also be characterized. Whilst we use the example of the oxytocin/ vasopressin system, this method can also be used to study other receptors and ion channels that play a role in uterine contraction and relaxation to advance the understanding of human uterine physiology and pathophysiology.

Long-term childhood outcomes after interventions for prevention and management of preterm birth

Globally, preterm birth rates are rising and have a significant impact on neonatal morbidity and mortality. Preterm birth remains difficult to prevent and a number of strategies for preterm birth prevention (progesterone, cervical pessaries, cervical cerclage, tocolytics, and antibiotics) have been identified. While some of these show more promise, there is a paucity of evidence regarding the long-term effects of these strategies on childhood outcomes. Strategies used to improve the health of babies if born preterm, such as antenatal magnesium sulfate for fetal neuroprotection and antenatal corticosteroids for fetal lung maturation, show evidence of short-term benefit but lack large-scale follow-up data of long-term childhood outcomes. Future research on preterm birth interventions should include long-term follow-up of the children, ideally with similar outcome measures to allow for future meta-analyses.

Treatment of spontaneous preterm labour with retosiban: a phase II pilot dose-ranging study

Aims

The aims of the present study were to investigate the maternal, fetal and neonatal safety and tolerability, pharmacodynamics and pharmacokinetics of intravenous (IV) retosiban in pregnant women with spontaneous preterm labour (PTL) between 34^0/7 and 35^6/7 weeks' gestation.

Methods

In parts A and B of a three‐part, double‐blind, placebo‐controlled, multicentre study, women were randomized 3:1 (Part A) or 2:1 (Part B) to either 12‐h IV retosiban followed by a single dose of oral placebo (R‐P) or 12‐h IV placebo followed by single‐dose oral retosiban (P‐R).

Results

A total of 29 women were randomized; 20 to R‐P and nine to P‐R. An integrated analysis found that adverse events were infrequent in mothers/newborns and consistent with events expected in the population under study or associated with confounding factors. Retosiban was rapidly absorbed after oral administration, with an observed half‐life of 1.45 h. Efficacy analyses included 19 women. While not statistically significant, those receiving R‐P more frequently achieved uterine quiescence in 6 h (R‐P, 63%; 95% credible interval [CrI]: 38, 84; P‐R, 43%; 95% CrI: 12, 78) and more achieved a reduction of ≥50% in uterine contractions in 6 h (R‐P, 63%; 95% CrI: 38, 84; P‐R, 29%; 95% CrI: 4, 64). The number of days to delivery was increased in women receiving R‐P (median 26 days for R‐P vs. 13 days for P‐R).

Conclusions

Intravenous retosiban has a favourable safety and tolerability profile and might prolong pregnancies in women with PTL. The study provides the rationale and dosing strategy for further evaluation of the efficacy of retosiban in the treatment of PTL.

Drug delivery to the human and mouse uterus using immunoliposomes targeted to the oxytocin receptor

BACKGROUND

The ability to provide safe and effective pharmacotherapy during obstetric complications, such as preterm labor or postpartum hemorrhage, is hampered by the systemic toxicity of therapeutic agents leading to adverse side effects in the mother and fetus. Development of novel strategies to target tocolytic and uterotonic agents specifically to uterine myocytes would improve therapeutic efficacy while minimizing the risk of side effects. Ligand-targeted liposomes have emerged as a reliable and versatile platform for targeted drug delivery to specific cell types, tissues or organs.

OBJECTIVE

Our objective was to develop a targeted drug delivery system for the uterus utilizing an immunoliposome platform targeting the oxytocin receptor.

STUDY DESIGN

We conjugated liposomes to an antibody that recognizes an extracellular domain of the oxytocin receptor. We then examined the ability of oxytocin receptor-targeted liposomes to deliver contraction-blocking (nifedipine, salbutamol and rolipram) or contraction-enhancing (dofetilide) agents to strips of spontaneously contracting myometrial tissue in vitro (human and mouse). We evaluated the ability of oxytocin receptor-targeted liposomes to localize to uterine tissue in vivo, and assessed if targeted liposomes loaded with indomethacin were capable of preventing lipopolysaccharide-induced preterm birth in mice.

RESULTS

Oxytocin receptor-targeted liposomes loaded with nifedipine, salbutamol or rolipram consistently abolished human myometrial contractions in vitro, while oxytocin receptor-targeted liposomes loaded with dofetilide increased contraction duration. Nontargeted control liposomes loaded with these agents had no effect. Similar results were observed in mouse uterine strips. Following in vivo administration to pregnant mice, oxytocin receptor-targeted liposomes localized specifically to the uterine horns and mammary tissue. Targeting increased localization to the uterus 7-fold. Localization was not detected in the maternal brain or fetus. Targeted and nontargeted liposomes also localized to the liver. Oxytocin receptor-targeted liposomes loaded with indomethacin were effective in reducing rates of preterm birth in mice, whereas nontargeted liposomes loaded with indomethacin had no effect.

CONCLUSION

Our results demonstrate that oxytocin receptor-targeted liposomes can be used to either inhibit or enhance human uterine contractions in vitro. In vivo, the liposomes localized to the uterine tissue of pregnant mice and were effective in delivering agents for the prevention of inflammation-induced preterm labor. The potential clinical advantage of targeted liposomal drug delivery to the myometrium is reduced dose and reduced toxicity to both mother and fetus.

Spasmodic versus spasmolytic activities of Euphorbia spinidens extract on rat isolated uterus

Preterm contraction of uterus is a main cause of miscarriages and preterm labour. Euphorbia known as Ferphion in Iranian traditional medicine texts like Al-Hawi, is reported for prevention of preterm labour. Therefore, the objective of this research was to investigate the effect of Euphorbia spinidens Bornm. Ex Prokh. on motility of rat uterus. Uterine horns were isolated form non-pregnant female rats pretreated with estrogen. E. spinidens hydroalcoholic extract was examined on KCl (80 mM) induced and spontaneous periodic contraction in isolate uterine strips suspended in an organ bath and compared with nifedipine and ritodrine. In isolated rat uterine strips, E. spinidens extract (1-500 µg/mL) showed mixed effects. At lower concentrations, firstly potentiated the spontaneous periodic contraction, while in concentrations above 256 µg/mL the spontaneous periodic contractions were completely attenuated. These findings demonstrated that although lower concentrations of hydroalcoholic extract potentiated the spontaneous periodic contraction of rat uterine smooth muscle, but at higher concentrations it had inhibitory effect on rat uterus contraction.

The oxytocin receptor antagonist, Atosiban, activates pro-inflammatory pathways in human amnion via G(αi) signalling

Oxytocin (OT) plays an important role in the onset of human labour by stimulating uterine contractions and promoting prostaglandin/inflammatory cytokine synthesis in amnion via oxytocin receptor (OTR) coupling. The OTR-antagonist, Atosiban, is widely used as a tocolytic for the management of acute preterm labour. We found that in primary human amniocytes, Atosiban (10 μM) signals via PTX-sensitive Gαi to activate transcription factor NF-κB p65, ERK1/2, and p38 which subsequently drives upregulation of the prostaglandin synthesis enzymes, COX-2 and phospho-cPLA2 and excretion of prostaglandins (PGE2) (n = 6; p < 0.05, ANOVA). Moreover, Atosiban treatment increased expression and excretion of the inflammatory cytokines, IL-6 and CCL5. We also showed that OT-simulated activation of NF-κB, ERK1/2, and p38 and subsequent prostaglandin and inflammatory cytokine synthesis is via Gαi-2 and Gαi-3 but not Gαq, and is not inhibited by Atosiban. Activation or exacerbation of inflammation is not a desirable effect of tocolytics. Therefore therapeutic modulation of the OT/OTR system for clinical management of term/preterm labour should consider the effects of differential G-protein coupling of the OTR and the role of OT or selective OTR agonists/antagonists in activating proinflammatory pathways.

Tocolysis for inhibiting preterm birth in extremely preterm birth, multiple gestations and in growth-restricted fetuses: a systematic review and meta-analysis

This systematic review was to identify available evidence on the effectiveness of tocolysis in inhibiting preterm delivery for women with threatened extremely preterm birth, multiple gestations, and growth-restricted babies, and their infants' outcomes. A comprehensive search using MEDLINE, Embase, the Cochrane Library, CINAHL, POPLINE and the WHO Global Health Library databases was conducted on 14 February 2014. For selection criteria, randomized controlled trials and non-randomized studies that compared tocolysis treatment to placebo or no treatment were considered. Selection of eligible studies, critical appraisal of the included studies, data collection, meta-analyses, and assessment of evidence quality were performed in accordance with the Cochrane Collaboration's guidance and validated assessment criteria. The search identified seven studies for extremely preterm birth, in which three were randomized controlled trials (RCTs) and four were non-randomized studies (non-RCTs). There were no eligible studies identified for women with multiple pregnancy and growth-restricted fetuses. Meta-analyses indicated no significant difference was found for the relative effectiveness of tocolytics versus placebo for prolonging pregnancy in women with extremely preterm birth (RR 1.04, 95% CI 0.83 to 1.31) or reducing the rate of perinatal deaths (RR 2.22, 95% CI 0.26 to 19.24). In summary, there is no evidence to draw conclusions on the effectiveness of tocolytic therapy for women with threatened extremely preterm birth, multiple gestations, and growth-restricted babies.

Effects of the Oral Oxytocin Receptor Antagonist Tocolytic OBE001 on Reproduction in Rats

BACKGROUND

OBE001 is a novel, orally active nonpeptide oxytocin receptor antagonist under development for the treatment of preterm labor and improvement in embryo implantation and pregnancy rate in assisted reproductive technology (ART). The reproductive safety of OBE001 was evaluated in customized fertility embryonic development (FER)/early embryonic development (EED) and fetal development (FD) and pre/postnatal development (PPN) studies mimicking clinical exposure scenarios.

METHODS

Oral OBE001 was evaluated at doses of 37.5, 75, and 125 mg/kg/d in female rats during a FER/EED study (from premating to implantation) and throughout FD during a FD/PPN study.

RESULTS

No OBE001 effects were observed during the FER/EED study. The FD/PPN study did not result in adverse OBE001 effects in females allowed to litter, their offspring, and second-generation fetuses. Females at 125 mg/kg/d who underwent cesarean section before term had slight reductions in body weights and food consumption, and associated fetuses had slightly delayed ossification of skull bones, which was not adverse in the absence of effects on live offspring.

CONCLUSION

OBE001 at up to 125 mg/kg/d had no effects on EED and no adverse effects on FD and postnatal development of rats. These results constitute an important step toward the development of OBE001 in preterm labor and ART indications.

Abdominal surgery in pregnancy--an interdisciplinary challenge

BACKGROUND

Abdominal operations are performed during ca. 2% of all pregnancies. They represent an unusual situation not only for the patient, but also for the involved surgeons and anesthesiologists. Appendectomy, followed by cholecystectomy are the two most common types of operation performed during pregnancy. Special questions arise with regard to the peri- and intraoperative management and the optimal surgical approach.

METHOD

This review is based on pertinent articles retrieved by a selective search in the PubMed database.

RESULTS

The question of laparoscopy versus laparotomy during pregnancy has been addressed to date only in case series and a few meta-analyses. Two meta-analyses have shown a significantly higher rate of miscarriage after laparoscopic, compared to open, appendectomy (relative risk [RR] 1.91, 95% confidence interval [CI] 1.31-2.77). The risk of preterm birth is also somewhat higher after laparoscopic appendectomy according to one meta-analysis on this subject (RR 1.44, 95% CI 0.78-1.76), but significantly lower according to another meta-analysis (2.1% vs. 8.1%, p<0.0001). For cholecystectomy, laparoscopy was associated with a lower miscarriage rate than laparotomy (1 in 89 cases, versus 2 in 69 cases), but with a somewhat higher preterm birth rate (6 in 89 cases, versus 2 in 69 cases). Delay or non-performance of surgery in a patient with appendicitis or cholecystitis can lead to additional hospitalizations, a higher miscarriage rate, premature rupture of the membranes, and preterm birth.

CONCLUSION

Laparoscopy in experienced hands is safe even during pregnancy, with the recognized advantages of minimally invasive surgery, yet it carries a higher miscarriage rate than laparotomy, with a comparable preterm birth rate. Before surgery, patients should be thoroughly informed about the operation they are about to undergo and the advantages and disadvantages of the available surgical approaches.

Antenatal exposure to indomethacin increases the risk of severe intraventricular hemorrhage, necrotizing enterocolitis, and periventricular leukomalacia: a systematic review with metaanalysis

OBJECTIVE

The purpose of this study was to provide an updated summary of the literature regarding the effects of tocolysis with indomethacin on neonatal outcome by systematically reviewing previously and recently reported data.

STUDY DESIGN

All previously reported studies pertaining to indomethacin tocolysis and neonatal outcomes along with recently reported data were identified with the use of electronic databases that had been supplemented with references that were cited in original studies and review articles. Observational studies that compared neonatal outcomes among preterm infants who were exposed and not exposed to indomethacin were included in this systematic review. Data were extracted and quantitative analyses were performed on those studies that assessed the neonatal outcomes of patients that received antenatal tocolysis with indomethacin.

RESULTS

Twenty-seven observational studies that met criteria for systematic review and metaanalysis were identified. These studies included 8454 infants, of whom 1731 were exposed to antenatal indomethacin and 6723 were not exposed. Relative risks with 95% confidence intervals were calculated for dichotomous outcomes with the use of random and fixed-effects models. Metaanalysis revealed no statistically significant differences in the rates of respiratory distress syndrome, patent ductus arteriosus, neonatal mortality rate, neonatal sepsis, bronchopulmonary dysplasia, or intraventricular hemorrhage (all grades). However, antenatal exposure to indomethacin was associated with an increased risk of severe intraventricular hemorrhage (grade III-IV based on Papile's criteria; relative risk, 1.29; 95% confidence interval, 1.06-1.56), necrotizing enterocolitis (relative risk, 1.36; 95% confidence interval, 1.08-1.71), and periventricular leukomalacia (relative risk, 1.59; 95% confidence interval, 1.17-2.17).

CONCLUSION

The use of indomethacin as a tocolytic agent for preterm labor is associated with an increased risk for severe intraventricular hemorrhage, necrotizing enterocolitis, and periventricular leukomalacia.

Management of pregnant patients undergoing general surgical procedures

Pregnant patients have a 0.2% to 0.75% chance of developing a medical condition that requires a general surgical intervention during pregnancy. To safely and appropriately care for patients, surgeons must be cognizant of the maternal physiologic changes in pregnancy as well as of the unique risk to both mothers and fetuses of diagnostic modalities, anesthetic care, operative intervention, and postoperative management. Surgeons can be assured that, if these risks are understood and considered, operating during pregnancy, even in the abdomen, can be safely undertaken.

Medical Transfer of Patients in Preterm Labor: Treatments and Tocolytics

Abstract Objective. To examine the epidemiology, effectiveness, and safety of tocolytics, and the variation in use of standard treatments and predictive testing for women in preterm labor (PTL) transported to tertiary care. Methods. This was a health record review of consecutive PTL patients (<38 weeks gestation) transported to a tertiary care facility by Ontario's air and land critical care transport service between January 1, 2006 and January 1, 2011. The primary outcome was the effectiveness of tocolytics in decreasing the frequency of contractions and incidence of delivery. Secondary outcomes included the type of tocolytics used, adverse events (defined a priori), use of standard treatments (corticosteroid, antibiotic), and use of predictive tests (cervical length measurement, fetal fibronectin). We report descriptive statistics and relative risk of contractions decreasing with tocolytics with 95% confidence intervals. Results. Of the 510 transports reviewed, 488 met all inclusion criteria with the following characteristics: mean age 26.1 years, mean gestational age 31.2 weeks, mean transport time 80 minutes, 61.0% multiparous, 13.3% twins, mean initial dilatation 1.8 cm, contraction <8 min apart 67.7%, and 66.8% from Northern Ontario. Tocolytics were used in 206 (42.2%), with nonsteroidal anti-inflammatory drugs and nitroglycerine being used most frequently. Eleven (2.3%) patients delivered during transport, 4 (36.4%) of which received tocolytics with relative risk (RR) 0.8 (95%CI 0-2.0), and number needed to treat (NNT) 165 (31.5-299.3). Among the 311 (63.7%) patients for which change in contractions was documented, 140 (45%) received tocolytics and of these patients, contractions decreased in 94 (67%), with an RR 0.6 (95%CI 0.3-0.9) and NNT 4.6 (3.1-6.2). Adverse events were documented in 67 (14%) patients (most commonly tachycardia 5.8%). Steroids were appropriately used in 268 (54.9%) patients and antibiotics were appropriately used in 286 (58.6%) patients. Predictive testing was performed in only 19 (3.9%) patients. Conclusions. Tocolytics were associated with decreased contraction frequency in more than two-thirds of those treated. However, nearly half those who did not receive the treatment also had decreased contractions, and the effect did not reach statistical significance. Variation in the type of tocolytic drug used suggests a need for clinical practice guidelines for tocolytic use during transport of PTL patients.