Short-term tocolytics for preterm delivery - current perspectives

Accelerating adverse pregnancy outcomes research amidst rising medication use: parallel retrospective cohort analyses for signal prioritization

BACKGROUND

Pregnant women are significantly underrepresented in clinical trials, yet most of them take medication during pregnancy despite the limited safety data. The objective of this study was to characterize medication use during pregnancy and apply propensity score matching method at scale on patient records to accelerate and prioritize the drug effect signal detection associated with the risk of preterm birth and other adverse pregnancy outcomes.

METHODS

This was a retrospective study on continuously enrolled women who delivered live births between 2013/01/01 and 2022/12/31 (n = 365,075) at Providence St. Joseph Health. Our exposures of interest were all outpatient medications prescribed during pregnancy. We limited our analyses to medication that met the minimal sample size (n = 600). The primary outcome of interest was preterm birth. Secondary outcomes of interest were small for gestational age and low birth weight. We used propensity score matching at scale to evaluate the risk of these adverse pregnancy outcomes associated with drug exposure after adjusting for demographics, pregnancy characteristics, and comorbidities.

RESULTS

The total medication prescription rate increased from 58.5 to 75.3% (P < 0.0001) from 2013 to 2022. The prevalence rate of preterm birth was 7.7%. One hundred seventy-five out of 1329 prenatally prescribed outpatient medications met the minimum sample size. We identified 58 medications statistically significantly associated with the risk of preterm birth (P ≤ 0.1; decreased: 12, increased: 46).

CONCLUSIONS

Most pregnant women are prescribed medication during pregnancy. This highlights the need to utilize existing real-world data to enhance our knowledge of the safety of medications in pregnancy. We narrowed down from 1329 to 58 medications that showed statistically significant association with the risk of preterm birth even after addressing numerous covariates through propensity score matching. This data-driven approach demonstrated that multiple testable hypotheses in pregnancy pharmacology can be prioritized at scale and lays the foundation for application in other pregnancy outcomes.

Possible Efficacy of Vaginal Progesterone on Asymptomatic Women with a Short Cervix after 24 Weeks of Gestation: A Historical Cohort Study in Japan

Introduction

Few studies have explored the preventive efficacy of vaginal progesterone (VD) treatment for preterm delivery (PTD) in Japanese clinical practice. In this study, the efficacy of the VD treatment in pregnant women with a short cervix (sCX) diagnosed after 24 weeks is evaluated, focusing on perinatal outcomes.

Methods

A retrospective historical cohort study. Clinical data of 273 singleton women hospitalized for preventing PTD were extracted. Inclusion criteria are diagnosed sCX at 24-33 weeks. We excluded women with factors including treatment start before 24 weeks, medically induced PTD, PTD on admission day, and fetal demise. Consequently, logistic regression analyses were conducted on data from 79 women during Period 1 (November 2015 to March 2018, using prolonged intravenous ritodrine hydrochloride) and 82 women during Period 2 (August 2018 to August 2022, implementing VD treatment), adjusting maternal age, parity, body mass index, gestational age, cervical length, and histological chorioamnionitis. The primary outcomes involved PTD <37 and <34 weeks and neonatal intensive care unit admission. Secondary outcomes included the interval from the diagnosis of sCX to delivery <14 and <28 days, infant intubation, and surfactant administration. Since VD use is off-label in Japan, we obtained written informed consent prior to treatment.

Results

VD treatment (Period 2) significantly decreased the incidence of PTD (birth < 37 weeks) (adjusted odds ratios [ORs] 0.43, 95% confidence intervals [CIs] 0.19-0.96), impending delivery within 14 and 28 days after confirming sCX (adjusted OR 0.12, 95% CI 0.06-0.72; adjusted OR 0.25, 95% CI 0.09-0.74, respectively), and neonatal intubation rate (adjusted OR 0.17, 95% CI 0.04-0.75).

Conclusions

The VD treatment can prevent PTD in asymptomatic women with sCX diagnosed after 24 weeks of gestation. Although further validation is warranted, these findings may contribute to expanding the use of VD treatment in Japanese clinical practice.

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.

Efficacy of Transdermal Nitroglycerin Patch for the Arrest of Preterm Labor: A Retrospective Study

Background Transdermal nitroglycerin (NTG) is a potent smooth muscle relaxant acting as a tocolytic agent by acting on the uterine muscles. The transdermal patch allows for continuous and controlled release of NTG through the skin into the bloodstream. This method offers the advantage of sustained drug delivery over a prolonged period. Objective of the study The study aimed to evaluate the efficacy of NTG patches for the arrest of preterm labor. Materials and methods This retrospective study comprised 100 patients admitted to our tertiary care center, ranging from 27 to 35 weeks of gestation, exhibiting preterm labor, uterine contractions, effacement, and dilatation of the cervix, without comorbidities and complications. Results In this study, it was observed that the incidence of preterm labor was higher among women aged 21-25 years. Pregnancy duration was extended by an average of approximately 28.63 days in our study cohort, with 90% of patients experiencing a prolongation of pregnancy to 48 hours after the application of a transdermal NTG patch. Parity distribution showed 50% of patients having a parity of G2-G4 and 30% being primigravida. However, 40% of the participants reported experiencing side effects, including headaches (15%) and local reactions (25%), while 60% did not experience any adverse effects. Conclusion In this study we found that the application of transdermal NTG patches led to a mean prolongation of pregnancy by 28.63 days, allowing time for the administration of steroids and fetal maturation. The inhibition of preterm contractions was successful, with an efficacy rate of 92%. These findings suggest the potential effectiveness of transdermal NTG patches as a tocolytic agent in managing preterm labor. However, the occurrence of side effects highlights the importance of careful monitoring and management during treatment.

Effects of polydimethylsiloxane membrane surface treatments on human uterine smooth muscle cell strain response

In the United States, 1 in 10 infants are born preterm. The majority of neonatal deaths and nearly a third of infant deaths are linked to preterm birth. Preterm birth is initiated when the quiescent state of the uterus ends prematurely, leading to contractions and parturition beginning as early as 32 weeks, though the origins are not well understood. To enable research and discovery of therapeutics with potential to better address preterm birth, the capability to study isolated cell processes of pregnant uterine tissue in vitro is needed. Our development of an in vitro model of the myometrium utilizing human uterine smooth muscle cells (uSMCs) responsible for contractions provides a methodology to examine cellular mechanisms of late-stage pregnancy potentially involved in preterm birth. We discuss culture of uSMCs on a flexible polydimethylsiloxane (PDMS) substrate functionalized with cationic poly-l-lysine (PLL), followed by extracellular matrix (ECM) protein coating. Previous work exploring uSMC behavior on PDMS substrates have utilized collagen-I coatings, however, we demonstrated the first exploration of human uSMC response to strain on fibronectin-coated flexible membranes, importantly reflecting the significant increase of fibronectin content found in the myometrial ECM during late-stage pregnancy. Using the model we developed, we conducted proof-of-concept studies to investigate the impact of substrate strain on uSMC cell morphology and gene expression. It was found that PLL and varied ECM protein coatings (collagen I, collagen III, and fibronectin) altered cell nuclei morphology and density on PDMS substrates. Additionally, varied strain rates applied to uSMC substrates significantly impacted uSMC gene expression of IL-6, a cytokine associated with instances of preterm labor. These results suggest that both surface and mechanical properties of in vitro systems impact primary human uSMC phenotype and offer uSMC culture methodologies that can be utilized to further the understanding of cellular pathways involved in the uterus under mechanical load.

Nanomedicine strategies to improve therapeutic agents for the prevention and treatment of preterm birth and future directions

The World Health Organisation (WHO) estimates 15 million babies worldwide are born preterm each year, with 1 million infant mortalities and long-term morbidity in survivors. Whilst the past 40 years have provided some understanding in the causes of preterm birth, along with development of a range of therapeutic options, notably prophylactic use of progesterone or uterine contraction suppressants (tocolytics), the number of preterm births continues to rise. Existing therapeutics used to control uterine contractions are restricted in their clinical use due to pharmacological drawbacks such as poor potency, transfer of drugs to the fetus across the placenta and maternal side effects from activity in other maternal systems. This review focuses on addressing the urgent need for the development of alternative therapeutic systems with improved efficacy and safety for the treatment of preterm birth. We discuss the application of nanomedicine as a viable opportunity to engineer pre-existing tocolytic agents and progestogens into nanoformulations, to improve their efficacy and address current drawbacks to their use. We review different nanomedicines including liposomes, lipid-based carriers, polymers and nanosuspensions highlighting where possible, where these technologies have already been exploited e.g. liposomes, and their significance in improving the properties of pre-existing therapeutic agents within the field of obstetrics. We also highlight where active pharmaceutical agents (APIs) with tocolytic properties have been used for other clinical indications and how these could inform the design of future therapeutics or be repurposed to diversify their application such as for use in preterm birth. Finally we outline and discuss the future challenges.

Prevention of Preterm Labor by Isosorbide Dinitrate and Nitroglycerin Patch

BACKGROUND

Preterm labor is one of the most important causes of hospitalization during pregnancy and can lead to serious complications in neonates.

OBJECTIVE

This study aims to compare the effect of transdermal nitroglycerin (TNG) patches and sublingual tablets of Isosorbide dinitrate (ISD) for the prevention of preterm delivery.

METHODS

A total of 110 healthy pregnant women aged 18-35 years with a healthy and alive fetus and gestational age between 24-34 weeks who had at least 8 regular uterine contractions per hour were included in this single-blinded clinical trial. After exclusion, the women were randomly divided into TNG (n = 50) and ISD (n = 49) groups. After the first dose of medication (TNG or ISD), patients who developed complications such as hypotension, headache, or both, were also excluded from the study.

RESULTS

A total of 58 patients completed the treatment course (29 patients in each group). A significant difference in delayed preterm labor and recovery time was reported between the TNG and ISD groups.

CONCLUSION

Complications and the number of contractions were not statistically different in the two groups. We concluded that the TNG patch is more effective than ISD in delaying labor. Both drugs are likely to have a similar incidence of side effects.

Next generation strategies for preventing preterm birth

Preterm birth (PTB) is defined as delivery before 37 weeks of gestation. Globally, 15 million infants are born prematurely, putting these children at an increased risk of mortality and lifelong health challenges. Currently in the U.S., there is only one FDA approved therapy for the prevention of preterm birth. Makena is an intramuscular progestin injection given to women who have experienced a premature delivery in the past. Recently, however, Makena failed a confirmatory trial, resulting the Center for Drug Evaluation and Research's (CDER) recommendation for the FDA to withdrawal Makena's approval. This recommendation would leave clinicians with no therapeutic options for preventing PTB. Here, we outline recent interdisciplinary efforts involving physicians, pharmacologists, biologists, chemists, and engineers to understand risk factors associated with PTB, to define mechanisms that contribute to PTB, and to develop next generation therapies for preventing PTB. These advances have the potential to better identify women at risk for PTB, prevent the onset of premature labor, and, ultimately, save infant lives.

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.

Preterm Labor and Birth: A Clinical Review

When caring for women experiencing preterm labor and birth, nurses play a significant role as bedside experts, advocates, patient educators, and key members of the maternity care team. Enhanced expertise on clinical and professional knowledge of preterm labor and birth is crucial in prevention and treatment. As preterm birth rates continue to rise, perinatal nurses as well-informed clinical experts have the opportunity to offer innovative education, holistic assessments, and communication through shared decision-making models. Educating pregnant women about early recognition of preterm labor warning signs and symptoms allows for timely diagnosis, interventions, and treatment. Informed and collaborative nursing practice improves quality of clinical care based on individualized interactions. A clinical review of preterm labor and preterm birth is presented for perinatal nurses.

Different impacts of various tocolytic agents on increased risk of postoperative hemorrhage in preterm labor women undergoing Cesarean delivery: A population-based cohort study

Tocolytic agents, commonly used for inhibiting preterm labor, pose the risk of uterine atony, leading to postpartum hemorrhage. This study elucidated the effects of different tocolytic agents on postoperative hemorrhage among women in preterm labor undergoing Cesarean delivery (CD). Data from Taiwan National Health Insurance Research Database were analyzed. The risk (adjusted hazard ratio [aHR] and 95% confidence intervals [CI]) of postoperative hemorrhage in CD women with preterm labor diagnosis using tocolytic agents (Tocolysis group) comparing to CD women not using tocolytic agents (Control group) were determined. Impacts of different tocolytic agents in this regard were also investigated. Our data revealed that the incidence (11.7% vs 2.6%, P < .001) and risk (aHR: 1.21, 95% CI: 1.12-1.31, P < .001) of postoperative hemorrhage were significantly higher in the Tocolysis group (n = 15,317) than in the Control group (n = 244,096). Ritodrine was the most frequently used tocolytic agent (80.5%), followed by combination therapy (using more than one tocolytic agents) (8.5%), magnesium sulfate (MgSO4, 4.6%), calcium channel blockers (3.8%), betamimetics other than ritodrine (1.9%), prostaglandin synthase inhibitors (0.5%), and nitrates (0.1%). Barring those using calcium channel blockers and combination therapy, the use of MgSO4 (aHR: 1.43, P = .001), betamimetics other than ritodrine (aHR: 1.71, P < .001), prostaglandin synthase inhibitors (aHR: 2.67, P < .001) and nitrates (aHR: 3.30, P = .001) was associated with higher risks of postoperative hemorrhage compared with ritodrine. In conclusion, CD women with preterm labor diagnosis using tocolytic agents exhibit an increased risk of postoperative hemorrhage and that this risk varies with the use of different tocolytic agents.

Effects of immunization with heat-killed Mycobacterium vaccae on autism spectrum disorder-like behavior and epileptogenesis in a rat model of comorbid autism and epilepsy

Autism spectrum disorders (ASDs) and epilepsy are often comorbid. The basis for this co-occurrence remains unknown; however, inflammatory stressors during development are a shared risk factor. To explore this association, we tested the effect of repeated immunizations using a heat-killed preparation of the stress-protective immunoregulatory microbe Mycobacterium vaccae NCTC 11,659 (M. vaccae) on the behavioral and epileptogenic consequences of the combined stress-terbutaline (ST) rat model of ASD-like behavior/epilepsy. Repeated immunization of the dam with M. vaccae during pregnancy, followed by immunization of the pups after terbutaline injections, prevented the expression of ASD-like behavior but did not appear to protect against, and may have even enhanced, the spontaneous epileptogenic effects of ST. Maternal M. vaccae injections transferred an anti-inflammatory immunophenotype to offspring, and repeated injections across development prevented ST-induced increases in microglial density at early developmental time points in a region-specific manner. Despite epidemiological comorbidity between ASD/epileptic conditions and shared environmental risk factors, our results suggest that the expression of ASD-like behaviors, but perhaps not epileptogenesis, is sensitive to early anti-inflammatory intervention. These data provide support for the exploration of immunoregulatory strategies to prevent the negative neurodevelopmental behavioral effects of stressors during early critical periods.

Electrohysterogram for ANN-Based Prediction of Imminent Labor in Women with Threatened Preterm Labor Undergoing Tocolytic Therapy

Threatened preterm labor (TPL) is the most common cause of hospitalization in the second half of pregnancy and entails high costs for health systems. Currently, no reliable labor proximity prediction techniques are available for clinical use. Regular checks by uterine electrohysterogram (EHG) for predicting preterm labor have been widely studied. The aim of the present study was to assess the feasibility of predicting labor with a 7- and 14-day time horizon in TPL women, who may be under tocolytic treatment, using EHG and/or obstetric data. Based on 140 EHG recordings, artificial neural networks were used to develop prediction models. Non-linear EHG parameters were found to be more reliable than linear for differentiating labor in under and over 7/14 days. Using EHG and obstetric data, the <7- and <14-day labor prediction models achieved an AUC in the test group of 87.1 ± 4.3% and 76.2 ± 5.8%, respectively. These results suggest that EHG can be reliable for predicting imminent labor in TPL women, regardless of the tocolytic therapy stage. This paves the way for the development of diagnostic tools to help obstetricians make better decisions on treatments, hospital stays and admitting TPL women, and can therefore reduce costs and improve maternal and fetal wellbeing.

Preterm Birth, Inflammation and Infection: New Alternative Strategies for their Prevention

BACKGROUND

Worldwide, the progress in reducing neonatal mortality has been very slow. The rate of preterm birth has increased over the last 20 years in low-income and middle-income countries. Its association with increased mortality and morbidity is based on experimental studies and neonatal outcomes from countries with socioeconomic differences, which have considered implementing alternative healthcare strategies to prevent and reduce preterm births.

METHODS

Currently, there is no widely effective strategy to prevent preterm birth. Pharmacological therapies are directed at inhibiting myometrial contractions to prolong parturition. Some drugs, medicinal plants and microorganisms possess myorelaxant, anti-inflammatory and immunomodulatory properties that have proved useful in preventing preterm birth associated with inflammation and infection.

RESULTS

This review focuses on the existing literature regarding the use of different drugs, medicinal plants, and microorganisms that show promising benefits for the prevention of preterm birth associated with inflammation and infection. New alternative strategies involving the use of PDE-4 inhibitors, medicinal plants and probiotics could have a great impact on improving prenatal and neonatal outcomes and give babies the best start in life, ensuring lifelong health benefits.

CONCLUSION

Despite promising results from well-documented cases, only a small number of these alternative strategies have been studied in clinical trials. The development of new drugs and the use of medicinal plants and probiotics for the treatment and/or prevention of preterm birth is an area of growing interest due to their potential therapeutic benefits in the field of gynecology and obstetrics.

Melatonin for prevention of placental malperfusion and fetal compromise associated with intrauterine inflammation-induced oxidative stress in a mouse model

Melatonin has been shown to reduce oxidative stress and mitigate hypercoagulability. We hypothesized that maternally administered melatonin may reduce placental oxidative stress and hypercoagulability associated with exposure to intrauterine inflammation (IUI) and consequently improve fetoplacental blood flow and fetal sequelae. Mice were randomized to the following groups: control (C), melatonin (M), lipopolysaccharide (LPS; a model of IUI) (L), and LPS with melatonin (ML). The expression of antioxidant mediators in the placenta was significantly decreased, while that of pro-inflammatory mediators was significantly increased in L compared to C and ML. The systolic/diastolic ratio, resistance index, and pulsatility index in uterine artery (UtA) and umbilical artery (UA) were significantly increased in L compared with other groups when analyzed by Doppler ultrasonography. The expression of antioxidant mediators in the placenta was significantly decreased, while that of pro-inflammatory mediators was significantly increased in L compared to C and ML. Vascular endothelial damage and thrombi formation, as evidenced by fibrin deposits, were similarly increased in L compared to other groups. Maternal pretreatment with melatonin appears to modulate maternal placental malperfusion, fetal cardiovascular compromise, and fetal neuroinflammation induced by IUI through its antioxidant properties.

Administration of melatonin for prevention of preterm birth and fetal brain injury associated with premature birth in a mouse model

PROBLEM

Maternal inflammation leads to preterm birth and perinatal brain injury. Melatonin, through its anti-inflammatory effects, has been shown to be protective against inflammation-induced perinatal adverse effects. However, the immunomodulatory effects of melatonin on preterm birth and prematurity-related morbidity remain unknown. We wanted to investigate the effects of maternally administered melatonin on preterm birth and perinatal brain injury in a mouse model of maternal inflammation.

METHOD OF STUDY

A model of maternal inflammation employing lipopolysaccharide (LPS) was used to mimic the most common clinical scenario of preterm birth, that of maternal inflammation. Mice were randomly divided into the following groups: control, LPS, and LPS with melatonin pre-treatment. Doppler ultrasonography was used to obtain fetal and maternal hemodynamic measurements in utero. Placenta and fetal brains were harvested and analyzed for proinflammatory markers and signs of perinatal brain injury, respectively. Surviving offspring were assessed for neuromotor outcomes.

RESULTS

Melatonin pre-treatment lowered the level of proinflammatory cytokines in the uterus and the placenta, significantly improved LPS-induced acute fetal neuroinflammation and perinatal brain injury, as well as significantly upregulated the SIRT1/Nrf2 signaling pathway to reduce LPS-induced inflammation. Melatonin also prevented adverse neuromotor outcomes in offspring exposed to maternal inflammation.

CONCLUSION

Maternally administered melatonin modulated immune responses to maternal inflammation and decreased preterm birth and perinatal brain injury. These results suggest that melatonin, a safe treatment during pregnancy, may be used as an experimental therapeutic in clinical trials.

Comparative analysis of myometrial and vascular smooth muscle cells to determine optimal cells for use in drug discovery

Novel therapeutic regulators of uterine contractility are needed to manage preterm labor, induce labor and control postpartum hemorrhage. Therefore, we previously developed a high-throughput assay for large-scale screening of small molecular compounds to regulate calcium-mobilization in primary mouse uterine myometrial cells. The goal of this study was to select the optimal myometrial cells for our high-throughput drug discovery assay, as well as determine the similarity or differences of myometrial cells to vascular smooth muscle cells (VSMCs)-the most common off-target of current myometrial therapeutics. Molecular and pharmacological assays were used to compare myometrial cells from four sources: primary cells isolated from term pregnant human and murine myometrium, immortalized pregnant human myometrial (PHM-1) cells and immortalized non-pregnant human myometrial (hTERT-HM) cells. In addition, myometrial cells were compared to vascular SMCs. We found that the transcriptome profiles of hTERT-HM and PHM1 cells were most similar (r = 0.93 and 0.90, respectively) to human primary myometrial cells. Comparative transcriptome profiling of primary human myometrial transcriptome and VSMCs revealed 498 upregulated (p ≤ 0.01, log2FC≥1) genes, of which 142 can serve as uterine-selective druggable targets. In the high-throughput Ca²⁺-assay, PHM1 cells had the most similar response to primary human myometrial cells in OT-induced Ca²⁺-release (E_max = 195% and 143%, EC₅₀ = 30 nM and 120 nM, respectively), while all sources of myometrial cells showed excellent and similar robustness and reproducibility (Z' = 0.52 to 0.77). After testing a panel of 61 compounds, we found that the stimulatory and inhibitory responses of hTERT-HM cells were highly-correlated (r = 0.94 and 0.95, respectively) to human primary cells. Moreover, ten compounds were identified that displayed uterine-selectivity (≥5-fold E_max or EC₅₀ compared to VSMCs). Collectively, this study found that hTERT-HM cells exhibited the most similarity to primary human myometrial cells and, therefore, is an optimal substitute for large-scale screening to identify novel therapeutic regulators of myometrial contractility. Moreover, VSMCs can serve as an important counter-screening tool to assess uterine-selectivity of targets and drugs given the similarity observed in the transcriptome and response to compounds.

Incidence and risk factors of neonatal hypoglycemia after ritodrine therapy in premature labor: a retrospective cohort study

Background

Ritodrine hydrochloride (RD), a β2-adrenergic agonist, is widely used as a tocolytic medication to suppress premature labor, but can cause neonatal hypoglycemia, a potentially severe side effect. We examined the incidence and risk factors of neonatal hypoglycemia following maternal intravenous administration of RD.

Methods

This was a retrospective study of neonates, who had birth weight of ≥2000 g and were delivered at 36 weeks gestation or later in Kanazawa University Hospital from August 2013 to July 2016. We defined neonatal hypoglycemia as blood glucose level < 50 mg/dL. Neonates who were delivered without maternal intravenous RD or who were delivered 8 days or more after stopping maternal RD or who received oral RD were defined as the RD non-administration group, while those delivered within 7 days after stopping maternal RD were defined as the RD intravenous administration group. We examined the incidence and risk factors of RD-induced neonatal hypoglycemia by comparing these two groups.

Results

We enrolled 603 neonates in this study; 504 (83.6%) showed no neonatal hypoglycemia, while 99 (16.4%) exhibited neonatal hypoglycemia. The incidence of neonatal hypoglycemia was significantly higher (61.7%; 58/94) in the RD intravenous administration group than in the RD non-administration group (8.1%; 41/509) (p < 0.001). Binomial logistic regression analysis in the RD intravenous administration group showed that maternal age over 35 years (AOR: 3.385; 95% CI, 1.082–10.588, p = 0.036) and the interval to delivery from stopping intravenous administration of RD (AOR: 0.974; 95% CI, 0.953–0.996, p = 0.020) were independent factors associated with neonatal hypoglycemia. The cut-off value of the interval to predict the incidence of neonatal hypoglycemia was about 6 h (sensitivity 82.8%, specificity 63.9%).

Conclusions

The incidence of neonatal hypoglycemia was significantly increased by maternal intravenous administration of RD. We newly identified maternal age (over 35 years) and the interval to delivery from stopping intravenous administration of RD (within 6 h) as independent risk factors for neonatal hypoglycemia following maternal intravenous administration of RD. In cases with these risk factors, careful blood glucose monitoring is recommended for early detection and treatment of neonatal hypoglycemia.

Trauma in Pregnancy

Although trauma in pregnancy is rare, it is one of the most common causes of morbidity and mortality to pregnant women and fetus. Pathophysiology of trauma is generally time sensitive, and this is still true in pregnant patients, with the additional challenge of rare presentation and balancing the management of two patients concurrently. Successful resuscitation requires understanding the physiologic changes to the woman throughout the course of pregnancy. Ultimately, trauma management is best approached by prioritizing maternal resuscitation.

Advancing the analysis of terbutaline in urine samples using novel enzyme hydrolysis

Aim: To investigate the efficiency of two new fast-acting enzymes, recombinant arylsulfatase (IMCS-PSF) and mutant β-glucuronidase from Escherichia coli (IMCSzyme), in hydrolyzing specific terbutaline metabolites. Materials & methods: Two purified novel enzymes are used to precisely determine the amount of each metabolite in urine at different time points after oral administration. After systematically evaluating the hydrolysis efficiency of the novel enzymes compared with commercially available enzymes, these recently developed enzymes were applied to establish the separate urine concentration profiles of terbutaline and each metabolite. Results & discussion: The results highlight the highly efficient arylsulfatase enzyme expressed from E. coli for urine analysis of terbutaline while suggesting sulfoconjugates as the main terbutaline metabolites. Conclusion: This study demonstrated the high efficiency of the IMCS-PSF enzyme in hydrolyzing terbutaline conjugates in comparison with other enzyme reagents typically used for the analysis of terbutaline and sulfoconjugates are the main terbutaline metabolites in urine.

Repurposing simvastatin as a therapy for preterm labor: evidence from preclinical models

Preterm birth (PTB), the leading cause of neonatal morbidity and mortality, urgently requires novel therapeutic agents. Spontaneous PTB, resulting from preterm labor, is commonly caused by intrauterine infection/inflammation. Statins are well-established, cholesterol-lowering drugs that can reduce inflammation and inhibit vascular smooth muscle contraction. We show that simvastatin reduced the incidence of PTB in a validated intrauterine LPS-induced PTB mouse model, decreased uterine proinflammatory mRNA concentrations (IL-6, Cxcl1, and Ccl2), and reduced serum IL-6 concentration. In human myometrial cells, simvastatin reduced proinflammatory mediator mRNA and protein expression (IL-6 and IL-8) and increased anti-inflammatory cytokine mRNA expression (IL-10 and IL-13). Critically, simvastatin inhibited myometrial cell contraction, basally and during inflammation, and reduced phosphorylated myosin light chain concentration. Supplementation with mevalonate and geranylgeranyl pyrophosphate, but not farnesyl pyrophosphate, abolished these anticontractile effects, indicating that the Rho/Rho-associated protein kinase pathway is critically involved. Thus, simvastatin reduces PTB incidence in mice, inhibits myometrial contractions, and exhibits key anti-inflammatory effects, providing a rationale for investigation into the repurposing of statins to treat preterm labor in women.—Boyle, A. K., Rinaldi, S. F., Rossi, A. G., Saunders, P. T. K., Norman, J. E. Repurposing simvastatin as a therapy for preterm labor: evidence from preclinical models.

The effects of tocolysis on neonatal septic death in women with PPROM: a retrospective cohort study

PURPOSE

In women with preterm premature rupture of membranes (PPROM), particularly those with suspected chorioamnionitis, the benefit of tocolysis on neonatal outcome remains unclear. Our purpose was to evaluate the effect of tocolysis on neonatal septic death in women with PPROM with and without chorioamnionitis.

METHODS

A retrospective cohort study was used to address our study objective. We created a cohort consisting of all live births between 24 and 32 weeks' gestation that were registered in the Linked Birth and Infant Death data files (2009-2013) from the United States. Multivariate logistic regression was used to evaluate the effect of tocolysis on neonatal septic death at 7 and 28 days in births with and without chorioamnionitis.

RESULTS

Of the 46,968 births that met our inclusion criteria, tocolysis was administered to 6264 (13.3%). Tocolysis was more commonly prescribed to Caucasians, smokers, in multiple birth pregnancies, and to women with a history of preterm births. Tocolysis was not significantly associated with neonatal septic death at 7 days (OR 0.66, 95% CI 0.39-1.13) or at 28 days (OR 0.85, 95% CI 0.60-1.19). This was consistent in pregnancies with and without chorioamnionitis. Furthermore, tocolysis was associated with a reduced risk of neonatal septic death at 7 days when administered between 24 and 27 weeks' gestation (OR 0.44, 95% CI 0.22-0.88).

CONCLUSIONS

In the setting of PPROM, tocolysis does not appear to increase the risk of neonatal septic death at 7 and 28 days. Therefore, consideration should be given to its administration if clinically indicated.

Potent tocolytic activity of ethyl acetate fraction of Ananas comosus on rat and human uteri

The aim of this study was to investigate the tocolytic properties of Ananas comosus extract in rat and human uterine tissue in vitro and in the rat in vivo. Organ bath technique was employed to perform functional studies in vitro. The PhysioTel transmitter was implanted in SD rats to measure the changes in intrauterine pressure (IUP) in vivo. Analyses of F2 was performed using LC-HRMS. F2 produced a non-selective inhibitory response on oxytocin, prostaglandin F2α, acetylcholine and KCl. The inhibitory activity of F2 on oxytocin-induced contraction was not attenuated by propranolol, TEA, glibenclamide and indomethacin. Nω-Nitro-L-arginine, a nitric oxide synthase inhibitor, suppressed the maximal tocolytic activity of F2 by 25%. DIDS, an inhibitor of chloride channels, appeared to suppress the relaxant effect of F2. F2 suppressed the oxytocin-induced contraction in Ca²⁺ free solution. The in vivo tocolytic activity of F2 and ritodrine were observed in non-pregnant rats during the estrous stage by suppressing the frequency and amplitude of IUP peaks following intrauterine administration. Chemical analysis confirmed the involvement of citric acid in the tocolytic activity of F2. However, another less polar fraction is essential to accompany citric acid to produce such potent inhibitory response of F2. It is likely that F2 exerted tocolytic activity by multiple mechanisms, including antagonizing L-type Ca²⁺ channels, interfering with the intracellular Ca²⁺ release mechanism and releasing nitric oxide. F2 would be a promising candidate to develop as a tocolytic agent.

Comprehensive review of cardiovascular toxicity of drugs and related agents

Cardiovascular diseases are a leading cause of morbidity and mortality in most developed countries of the world. Pharmaceuticals, illicit drugs, and toxins can significantly contribute to the overall cardiovascular burden and thus deserve attention. The present article is a systematic overview of drugs that may induce distinct cardiovascular toxicity. The compounds are classified into agents that have significant effects on the heart, blood vessels, or both. The mechanism(s) of toxic action are discussed and treatment modalities are briefly mentioned in relevant cases. Due to the large number of clinically relevant compounds discussed, this article could be of interest to a broad audience including pharmacologists and toxicologists, pharmacists, physicians, and medicinal chemists. Particular emphasis is given to clinically relevant topics including the cardiovascular toxicity of illicit sympathomimetic drugs (e.g., cocaine, amphetamines, cathinones), drugs that prolong the QT interval, antidysrhythmic drugs, digoxin and other cardioactive steroids, beta-blockers, calcium channel blockers, female hormones, nonsteroidal anti-inflammatory, and anticancer compounds encompassing anthracyclines and novel targeted therapy interfering with the HER2 or the vascular endothelial growth factor pathway.

Pharmacokinetics, safety and tolerability of OBE022, a selective prostaglandin F2α receptor antagonist tocolytic: A first-in-human trial in healthy postmenopausal women

AIMS

Preterm birth remains a significant risk for later disability. The selective inhibition of the prostaglandin F_2α receptor has significant advantages for a tocolytic. The prodrug OBE022 and its metabolite OBE002 are novel prostaglandin F_2α receptor antagonists under development for treating preterm labour.

METHODS

We performed a prospective, first in human, Phase I, dose escalation, placebo-controlled, randomized trial at a clinical trial site in the UK. Placebo, single ascending doses of 10, 30, 100, 300, 1000 or 1300 mg, and multiple ascending doses over 7 days of 100, 300 or 1000 mg day^-1 ; were administered to postmenopausal female volunteers. Food interaction was additionally evaluated.

RESULTS

Subjects tolerated OBE022 well at all single and multiple doses. No clinically relevant changes in safety parameters were shown and there were no serious adverse events. Observations showed that prodrug OBE022 was readily absorbed and rapidly converted into its equally active stable metabolite OBE002. The plasma level of OBE002 rose with increasing doses, reaching exposure levels that were anticipated to be clinically relevant within 1 h following administration. There was no clinically significant food interaction, with peak exposures reduced to 80% and area under the curve staying bioequivalent. The mean half-life of OBE002 ranged between 8 and 11 h following administration of a single dose and 22-29 h after multiple doses.

CONCLUSIONS

Administration of OBE022 was safe and had favourable pharmacokinetic characteristics and no clinically relevant interaction with food. Our results allow further investigation of OBE022 in preterm labour patients.

Developmental neurotoxicity resulting from pharmacotherapy of preterm labor, modeled in vitro: Terbutaline and dexamethasone, separately and together

Terbutaline and dexamethasone are used in the management of preterm labor, often for durations of treatment exceeding those recommended, and both have been implicated in increased risk of neurodevelopmental disorders. We used a variety of cell models to establish the critical stages at which neurodifferentiation is vulnerable to these agents and to determine whether combined exposures produce a worsened outcome. Terbutaline selectively promoted the initial emergence of glia from embryonic neural stem cells (NSCs). The target for terbutaline shifted with developmental stage: at later developmental stages modeled with C6 and PC12 cells, terbutaline had little effect on glial differentiation (C6 cells) but impaired the differentiation of neuronotypic PC12 cells into neurotransmitter phenotypes. In contrast to the specificity shown by terbutaline, dexamethasone affected both neuronal and glial differentiation at all stages, impairing the emergence of both cell types in NSCs but with a much greater impairment for glia. At later stages, dexamethasone promoted glial cell differentiation (C6 cells), while shifting neuronal cell differentiation so as to distort the balance of neurotransmitter phenotypes (PC12 cells). Finally, terbutaline and dexamethasone interacted synergistically at the level of late stage glial cell differentiation, with dexamethasone boosting the ability of terbutaline to enhance indices of glial cell growth and neurite formation while producing further decrements in glial cell numbers. Our results support the conclusion that terbutaline and dexamethasone are directly-acting neuroteratogens, and further indicate the potential for their combined use in preterm labor to worsen neurodevelopmental outcomes.

High-Throughput Screening of Myometrial Calcium-Mobilization to Identify Modulators of Uterine Contractility

The uterine myometrium (UT-myo) is a therapeutic target for preterm labor, labor induction, and postpartum hemorrhage. Stimulation of intracellular Ca²⁺-release in UT-myo cells by oxytocin is a final pathway controlling myometrial contractions. The goal of this study was to develop a dual-addition assay for high-throughput screening of small molecular compounds, which could regulate Ca²⁺-mobilization in UT-myo cells, and hence, myometrial contractions. Primary murine UT-myo cells in 384-well plates were loaded with a Ca²⁺-sensitive fluorescent probe, and then screened for inducers of Ca²⁺-mobilization and inhibitors of oxytocin-induced Ca²⁺-mobilization. The assay exhibited robust screening statistics (Z´ = 0.73), DMSO-tolerance, and was validated for high-throughput screening against 2,727 small molecules from the Spectrum, NIH Clinical I and II collections of well-annotated compounds. The screen revealed a hit-rate of 1.80% for agonist and 1.39% for antagonist compounds. Concentration-dependent responses of hit-compounds demonstrated an EC₅₀ less than 10μM for 21 hit-antagonist compounds, compared to only 7 hit-agonist compounds. Subsequent studies focused on hit-antagonist compounds. Based on the percent inhibition and functional annotation analyses, we selected 4 confirmed hit-antagonist compounds (benzbromarone, dipyridamole, fenoterol hydrobromide and nisoldipine) for further analysis. Using an ex vivo isometric contractility assay, each compound significantly inhibited uterine contractility, at different potencies (IC₅₀). Overall, these results demonstrate for the first time that high-throughput small-molecules screening of myometrial Ca²⁺-mobilization is an ideal primary approach for discovering modulators of uterine contractility.