Factors influencing the participation of pregnant and lactating women in clinical trials: A mixed-methods systematic review.

BACKGROUND: Poor representation of pregnant and lactating women and people in clinical trials has marginalised their health concerns and denied the maternal-fetal/infant dyad benefits of innovation in therapeutic research and development. This mixed-methods systematic review synthesised factors affecting the participation of pregnant and lactating women in clinical trials, across all levels of the research ecosystem. METHODS AND FINDINGS: We searched 8 databases from inception to 14 February 2024 to identify qualitative, quantitative, and mixed-methods studies that described factors affecting participation of pregnant and lactating women in vaccine and therapeutic clinical trials in any setting. We used thematic synthesis to analyse the qualitative literature and assessed confidence in each qualitative review finding using the GRADE-CERQual approach. We compared quantitative data against the thematic synthesis findings to assess areas of convergence or divergence. We mapped review findings to the Theoretical Domains Framework (TDF) and Capability, Opportunity, and Motivation Model of Behaviour (COM-B) to inform future development of behaviour change strategies. We included 60 papers from 27 countries. We grouped 24 review findings under 5 overarching themes: (a) interplay between perceived risks and benefits of participation in women's decision-making; (b) engagement between women and the medical and research ecosystems; (c) gender norms and decision-making autonomy; (d) factors affecting clinical trial recruitment; and (e) upstream factors in the research ecosystem. Women's willingness to participate in trials was affected by: perceived risk of the health condition weighed against an intervention's risks and benefits, therapeutic optimism, intervention acceptability, expectations of receiving higher quality care in a trial, altruistic motivations, intimate relationship dynamics, and power and trust in medicine and research. Health workers supported women's participation in trials when they perceived clinical equipoise, had hope for novel therapeutic applications, and were convinced an intervention was safe. For research staff, developing reciprocal relationships with health workers, having access to resources for trial implementation, ensuring the trial was visible to potential participants and health workers, implementing a woman-centred approach when communicating with potential participants, and emotional orientations towards the trial were factors perceived to affect recruitment. For study investigators and ethics committees, the complexities and subjectivities in risk assessments and trial design, and limited funding of such trials contributed to their reluctance in leading and approving such trials. All included studies focused on factors affecting participation of cisgender pregnant women in clinical trials; future research should consider other pregnancy-capable populations, including transgender and nonbinary people. CONCLUSIONS: This systematic review highlights diverse factors across multiple levels and stakeholders affecting the participation of pregnant and lactating women in clinical trials. By linking identified factors to frameworks of behaviour change, we have developed theoretically informed strategies that can help optimise pregnant and lactating women's engagement, participation, and trust in such trials.

Effectiveness of care bundles for prevention and treatment of postpartum hemorrhage: a systematic review.

OBJECTIVE: Care bundles are a promising approach to reducing postpartum hemorrhage-related morbidity and mortality. We assessed the effectiveness and safety of care bundles for postpartum hemorrhage prevention and/or treatment. DATA SOURCES: We searched MEDLINE, Embase, Cochrane CENTRAL, Maternity and Infant Care Database, and Global Index Medicus (inception to June 9, 2023) and ClinicalTrials.gov and the International Clinical Trials Registry Platform (last 5 years) using a phased search strategy, combining terms for postpartum hemorrhage and care bundles. STUDY ELIGIBILITY CRITERIA: Peer-reviewed studies evaluating postpartum hemorrhage-related care bundles were included. Care bundles were defined as interventions comprising ≥3 components implemented collectively, concurrently, or in rapid succession. Randomized and nonrandomized controlled trials, interrupted time series, and before-after studies (controlled or uncontrolled) were eligible. METHODS: Risk of bias was assessed using RoB 2 (randomized trials) and ROBINS-I (nonrandomized studies). For controlled studies, we reported risk ratios for dichotomous outcomes and mean differences for continuous outcomes, with certainty of evidence determined using GRADE. For uncontrolled studies, we used effect direction tables and summarized results narratively. RESULTS: Twenty-two studies were included for analysis. For prevention-only bundles (2 studies), low-certainty evidence suggests possible benefits in reducing blood loss, duration of hospitalization, and intensive care unit stay, and maternal well-being. For treatment-only bundles (9 studies), high-certainty evidence shows that the E-MOTIVE intervention reduced risks of composite severe morbidity (risk ratio, 0.40; 95% confidence interval, 0.32-0.50) and blood transfusion for bleeding, postpartum hemorrhage, severe postpartum hemorrhage, and mean blood loss. One nonrandomized trial and 7 uncontrolled studies suggest that other postpartum hemorrhage treatment bundles might reduce blood loss and severe postpartum hemorrhage, but this is uncertain. For combined prevention/treatment bundles (11 studies), low-certainty evidence shows that the California Maternal Quality Care Collaborative care bundle may reduce severe maternal morbidity (risk ratio, 0.64; 95% confidence interval, 0.57-0.72). Ten uncontrolled studies variably showed possible benefits, no effects, or harms for other bundle types. Nearly all uncontrolled studies did not use suitable statistical methods for single-group pretest-posttest comparisons and should thus be interpreted with caution. CONCLUSION: The E-MOTIVE intervention improves postpartum hemorrhage-related outcomes among women delivering vaginally, and the California Maternal Quality Care Collaborative bundle may reduce severe maternal morbidity. Other bundle designs warrant further effectiveness research before implementation is contemplated.

Analysis of a maternal health medicines pipeline database 2000-2021: New candidates for the prevention and treatment of fetal growth restriction.

OBJECTIVE: The Accelerating Innovation for Mothers project established a new database of candidate medicines under development between 2000 and 2021 for five pregnancy-related conditions, including fetal growth restriction. The objective was to assess medicines for fetal growth restriction and their potential for clinical use globally. DESIGN: Landscape analysis. SETTING: Global (focus on low- and middle-income countries, LMICs). SAMPLE: Drugs, dietary supplements and biologics under investigation for prevention or treatment of fetal growth restriction. METHODS: A research pipeline database of medicines was created through searching AdisInsight, PubMed and various grant and clinical trial databases. Analysis of clinical and preclinical candidates were descriptive. MAIN OUTCOMES MEASURES: Fetal growth restriction candidates in clinical development were identified and ranked as high, medium or low potential based on prespecified criteria, including efficacy, safety and accessibility. RESULTS: Of the 444 unique candidates in the database across all five pregnancy-related conditions, 63 were for fetal growth restriction. Of these, 31 were in clinical development (phases I, II or III) and 32 were in preclinical development. Three candidates, aspirin, l-arginine and vitamin D, were ranked as having high potential as preventive agents. There were no high-potential candidates for treating fetal growth restriction, although five candidates were ranked as having medium potential: allylestrenol, dalteparin, omega-3 fatty acids, tadalafil, and United Nations International Multiple Micronutrient Antenatal Preparation (UNIMMAP). CONCLUSIONS: l-Arginine, aspirin and vitamin D are promising, high-potential preventative agents for fetal growth restriction. Based on the medicines pipeline, new pharmacological agents for fetal growth restriction are unlikely to emerge in the near future.

New medicines for spontaneous preterm birth prevention and preterm labour management: landscape analysis of the medicine development pipeline.

BACKGROUND: There are few medicines in clinical use for managing preterm labor or preventing spontaneous preterm birth from occurring. We previously developed two target product profiles (TPPs) for medicines to prevent spontaneous preterm birth and manage preterm labor. The objectives of this study were to 1) analyse the research and development pipeline of medicines for preterm birth and 2) compare these medicines to target product profiles for spontaneous preterm birth to identify the most promising candidates. METHODS: Adis Insight, Pharmaprojects, WHO international clinical trials registry platform (ICTRP), PubMed and grant databases were searched to identify candidate medicines (including drugs, dietary supplements and biologics) and populate the Accelerating Innovations for Mothers (AIM) database. This database was screened for all candidates that have been investigated for preterm birth. Candidates in clinical development were ranked against criteria from TPPs, and classified as high, medium or low potential. Preclinical candidates were categorised by product type, archetype and medicine subclass. RESULTS: The AIM database identified 178 candidates. Of the 71 candidates in clinical development, ten were deemed high potential (Prevention: Omega-3 fatty acid, aspirin, vaginal progesterone, oral progesterone, L-arginine, and selenium; Treatment: nicorandil, isosorbide dinitrate, nicardipine and celecoxib) and seven were medium potential (Prevention: pravastatin and lactoferrin; Treatment: glyceryl trinitrate, retosiban, relcovaptan, human chorionic gonadotropin and Bryophyllum pinnatum extract). 107 candidates were in preclinical development. CONCLUSIONS: This analysis provides a drug-agnostic approach to assessing the potential of candidate medicines for spontaneous preterm birth. Research should be prioritised for high-potential candidates that are most likely to meet the real world needs of women, babies, and health care professionals.

Systematic evaluation of the pre-eclampsia drugs, dietary supplements and biologicals pipeline using target product profiles.

BACKGROUND: The Accelerating Innovation for Mothers (AIM) project established a database of candidate medicines in research and development (R&D) between 2000 and 2021 for five pregnancy-related conditions, including pre-eclampsia. In parallel, we published target product profiles (TPPs) that describe optimal characteristics of medicines for use in preventing/treating pre-eclampsia. The study objective was to use systematic double screening and extraction to identify all candidate medicines being investigated for pre-eclampsia prevention/treatment and rank their potential based on the TPPs. METHODS: Adis Insight, Pharmaprojects, WHO international clinical trials registry platform (ICTRP), PubMed and grant databases were searched (Jan-May 2021). The AIM database was screened for all candidates being investigated for pre-eclampsia. Candidates in clinical development were evaluated against nine prespecified criteria from TPPs identified as key for wide-scale implementation, and classified as high, medium or low potential based on matching to the TPPs. Preclinical candidates were categorised by product type, archetype and medicine subclass. RESULTS: The AIM database identified 153 candidates for pre-eclampsia. Of the 87 candidates in clinical development, seven were classified as high potential (prevention: esomeprazole, L-arginine, chloroquine, vitamin D and metformin; treatment: sulfasalazine and metformin) and eight as medium potential (prevention: probiotic lactobacilli, dalteparin, selenium and omega-3 fatty acid; treatment: sulforaphane, pravastatin, rosuvastatin and vitamin B3). Sixty-six candidates were in preclinical development, the most common being amino acid/peptides, siRNA-based medicines and polyphenols. CONCLUSIONS: This is a novel, evidence-informed approach to identifying promising candidates for pre-eclampsia prevention and treatment - a vital step in stimulating R&D of new medicines for pre-eclampsia suitable for real-world implementation.

Glucocorticoids influence versican and chondroitin sulphate proteoglycan levels in the fetal sheep lung.

BACKGROUND: Prenatal glucocorticoid treatment decreases alveolar tissue volumes and facilitates fetal lung maturation, however the mechanisms responsible are largely unknown. This study examines whether changes in versican levels or sulphation patterns of chondroitin sulphate (CS) side chains, are associated with glucocorticoid-induced reductions in peri-alveolar tissue volumes. METHODS: Lung tissue was collected from 1) fetal sheep at 131 ± 0.1 days gestational age (GA) infused with cortisol (122-131d GA) to prematurely induce a pre-parturient-like rise in circulating cortisol, 2) fetal sheep at 143d GA bilaterally adrenalectomised (ADX) at 112d GA to remove endogenous cortisol and 3) fetal sheep at 124d GA in which bolus doses (2 × 11.4 mg) of betamethasone were administered to the pregnant ewe. The level and distribution of versican and CS glycosaminoglycans (GAG) were determined using immunohistochemistry (IHC). Fluorophore assisted carbohydrate electrophoresis (FACE) was used to determine changes in CS sulphation patterns. RESULTS: Cortisol infusion significantly decreased chondrotin-6-sulphate levels (C-6-S) to 16.4 ± 0.7 AU, compared with saline-infused fetuses (18.9 ± 0.7 AU: p = 0.04) but did not significantly alter the level of versican or chondroitin-4-sulphate (C-4-S). ADX significantly increased the level of C-4-S (28.2 ± 2.2 AU), compared with sham-operated fetuses (17.8 ± 2.0 AU; p = 0.006) without altering versican or C-6-S levels. Betamethasone significantly decreased versican, C-4-S and C-6-S in the fetal sheep lung (19.2 ± 0.9 AU, 24.9 ± 1.4 AU and 23.2 ± 1.0 AU, respectively), compared with saline-exposed fetuses (24.3 ± 0.4 AU, p = 0.0004; 33.3±0.6 AU, p = 0.0003; 29.8±1.3 AU, 0.03, respectively). CONCLUSIONS: These results indicate that glucocorticoids alter versican levels and CS side chain microstructure in alveolar lung tissue. Betamethasone appears to have a greater impact on versican and CS side chains than cortisol.

Intrauterine Growth Restriction Alters the Postnatal Development of the Rat Cerebellum.

Intrauterine growth restriction (IUGR) is a major cause of antenatal brain injury. We aimed to characterize cerebellar deficits following IUGR and to investigate the potential underlying cellular and molecular mechanisms. At embryonic day 18, pregnant rats underwent either sham surgery (controls; n = 23) or bilateral uterine vessel ligation to restrict blood flow to fetuses (IUGR; n = 20). Offspring were collected at postnatal day 2 (P2), P7, and P35. Body weights were reduced at P2, P7, and P35 in IUGR offspring (p < 0.05) compared with controls. At P7, the width of the external granule layer (EGL) was 30% greater in IUGR than control rats (p < 0.05); there was no difference in the width of the proliferative zone or in the density of Ki67-positive cells in the EGL. Bergmann glia were disorganized at P7 and P35 in IUGR pups, and by P35, there was a 10% decrease in Bergmann glial fiber density (p < 0.05) compared with controls. At P7, trophoblast antigen-2 (Trop2) mRNA and protein levels in the cerebellum were decreased by 88 and 40%, respectively, and astrotactin 1 mRNA levels were increased by 20% in the IUGR rats (p < 0.05) compared with controls; there was no difference in ASTN1 protein. The expressions of other factors known to regulate cerebellar development (astrotactin 2, brain-derived neurotrophic factor, erb-b2 receptor tyrosine kinase 4, neuregulin 1, sonic hedgehog and somatostatin) were not different between IUGR and control rats at P7 or P35. These data suggest that damage to the migratory scaffold (Bergmann glial fibers) and alterations in the genes that influence migration (Trop2 and Astn1) may underlie the deficits in postnatal cerebellar development following IUGR.

Differential short-term regional effects of early high dose erythropoietin on white matter in preterm lambs after mechanical ventilation.

Inadvertently injurious ventilation of preterm neonates in the delivery room can cause cerebral white matter (WM) inflammation and injury. We investigated the impact of an early high dose of recombinant human erythropoietin (EPO) on ventilation-induced WM changes in preterm lambs. Injurious ventilation, targeting a V(T) of 15 ml kg(-1) with no positive end-expiratory pressure, was initiated for 15 min in preterm lambs (0.85 gestation). Conventional ventilation was continued for a further 105 min. Lambs received either 5000 IU kg(-1) of EPO (EPREX®; Vent+EPO; n = 6) or vehicle (Vent; n = 8) via an umbilical vein at 4 ± 2 min. Markers of WM injury and inflammation were assessed using quantitative real-time PCR (qPCR) and immunohistochemistry and compared to a group of unventilated controls (UVC; n = 4). In Vent+EPO lambs compared to Vent lambs: (i) interleukin (IL)-1ß and IL-6 mRNA levels in the periventricular WM and IL-8 mRNA levels in the subcortical WM were higher (P < 0.05 for all); (ii) the density of microglia within the aggregations was not different in the periventricular WM and was lower in the subcortical WM (P = 0.001); (iii) the density of astrocytes was lower in the subcortical WM (P = 0.002); (iv) occludin and claudin-1 mRNA levels were higher in the periventricular WM (P < 0.02 for all) and (vi) the number of blood vessels with protein extravasation was lower (P < 0.05). Recombinant human EPO had variable regional effects within the WM when administered during injurious ventilation. The adverse short-term outcomes discourage the use of early high dose EPO administration in preterm ventilated babies.

Trop2: from development to disease.

BACKGROUND: Trop2 was first discovered as a biomarker of invasive trophoblast cells. Since then most research has focused on its role in tumourigenesis because it is highly expressed in the vast majority of human tumours and animal models of cancer. It is also highly expressed in stem cells and in many organs during development. RESULTS: We review the multifaceted role of Trop2 during development and tumourigenesis, including its role in regulating cell proliferation and migration, self-renewal, and maintenance of basement membrane integrity. We discuss the evolution of Trop2 and its related protein Epcam (Trop1), including their distinct roles. Mutation of Trop2 leads to gelatinous drop-like corneal dystrophy, whereas over-expression of Trop2 in human tumours promotes tumour aggressiveness and increases mortality. Although Trop2 expression is sufficient to promote tumour growth, the surprising discovery that Trop2-null mice have an increased risk of tumour development has highlighted the complexity of Trop2 signaling. Recently, studies have begun to identify the mechanisms underlying TROP2's functions, including regulated intramembrane proteolysis or specific interactions with integrin b1 and claudin proteins. CONCLUSIONS: Understanding the mechanisms underlying TROP2 signaling will clarify its role during development, aid in the development of better cancer treatments and unlock a promising new direction in regenerative medicine.

Human Amnion Epithelial Cells Modulate Ventilation-Induced White Matter Pathology in Preterm Lambs.

BACKGROUND: Preterm infants can be inadvertently exposed to high tidal volumes (VT) during resuscitation in the delivery room due to limitations of available equipment. High VT ventilation of preterm lambs produces cerebral white matter (WM) pathology similar to that observed in preterm infants who develop cerebral palsy. We hypothesized that human amnion epithelial cells (hAECs), which have anti-inflammatory and regenerative properties, would reduce ventilation-induced WM pathology in neonatal late preterm lamb brains. METHODS: Two groups of lambs (0.85 gestation) were used, as follows: (1) ventilated lambs (Vent; n = 8) were ventilated using a protocol that induces injury (VT targeting 15 ml/kg for 15 min, with no positive end-expiratory pressure) and were then maintained for another 105 min, and (2) ventilated + hAECs lambs (Vent+hAECs; n = 7) were similarly ventilated but received intravenous and intratracheal administration of 9 × 10(7) hAECs (18 × 10(7) hAECs total) at birth. Oxygenation and ventilation parameters were monitored in real time; cerebral oxygenation was measured using near-infrared spectroscopy. qPCR (quantitative real-time PCR) and immunohistochemistry were used to assess inflammation, vascular leakage and astrogliosis in both the periventricular and subcortical WM of the frontal and parietal lobes. An unventilated control group (UVC; n = 5) was also used for qPCR analysis of gene expression. Two-way repeated measures ANOVA was used to compare physiological data. Student's t test and one-way ANOVA were used for immunohistological and qPCR data comparisons, respectively. RESULTS: Respiratory parameters were not different between groups. Interleukin (IL)-6 mRNA levels in subcortical WM were lower in the Vent+hAECs group than the Vent group (p = 0.028). IL-1ß and IL-6 mRNA levels in periventricular WM were higher in the Vent+hAECs group than the Vent group (p = 0.007 and p = 0.001, respectively). The density of Iba-1-positive microglia was lower in the subcortical WM of the parietal lobes (p = 0.010) in the Vent+hAECs group but not in the periventricular WM. The number of vessels in the WM of the parietal lobe exhibiting protein extravasation was lower (p = 0.046) in the Vent+hAECs group. Claudin-1 mRNA levels were higher in the periventricular WM (p = 0.005). The density of GFAP-positive astrocytes was not different between groups. CONCLUSIONS: Administration of hAECs at the time of birth alters the effects of injurious ventilation on the preterm neonatal brain. Further studies are required to understand the regional differences in the effects of hAECs on ventilation-induced WM pathology and their net effect on the developing brain.

Mesenchymal glucocorticoid receptor regulates the development of multiple cell layers of the mouse lung.

Endogenous glucocorticoid (GC) hormones, signaling via the GC receptor (GR), are essential for normal lung development, and synthetic GCs are routinely used to treat respiratory disorders of very preterm babies. Germline GR knockout (GR(-/-)) mice show immature lung morphology and severe lung cellular hyperplasia during embryogenesis and die at birth due to respiratory failure. Two recent studies have reported contradictory results regarding the necessity for GR expression in specific lung germ layers during respiratory maturation. We further investigate in detail the lung phenotype in mice with a conditional deletion of GR in the endothelium, mesenchyme, and lung epithelium. We show that loss of GR in the mesenchyme alone produces a retarded lung phenotype almost identical to that of germline GR(-/-) mice, including severe postnatal lethality and lung cell hyperplasia. Loss of GR in lung epithelial cells and the endothelium had no gross effect on survival or lung morphology, but loss of epithelial GR caused increased cell proliferation in multiple compartments. Mesenchymal GR loss also produced increased epithelial cell proliferation, implying the existence of GC-regulated germ layer cross-talk. Protein levels of GR-mediated cell cycle regulators, including the cyclin-dependent kinase inhibitor p21(CIP1) and the growth factor midkine, were unaffected by mesenchymal GR deletion, yet expression of the extracellular matrix proteoglycan versican was up-regulated in the distal lung on loss of mesenchymal GR. These results show that GR-mediated signaling from the mesenchyme regulates respiratory maturation and ultimately survival at birth and that a key GR-repressed transcriptional target in lung mesenchymal cells is versican.

The drug drought in maternal health: an ongoing predicament.

We developed a comprehensive database of medicines that are used or are being investigated for pre-eclampsia or eclampsia, preterm birth or labour, postpartum haemorrhage, intrauterine growth restriction, and fetal distress and that were in active development between 2000 and 2021. A total of 444 candidates were identified: approximately half of candidates were in active development, two-thirds had been repurposed after initially being used for another condition, and just under half were in preclinical studies. Only 64 candidates were in active late-stage (phase 3) development as of Oct 25, 2021, and given the slow pace of biomedical development, it could take years before any of these products eventually make it to market. A lack of innovation for maternal health medicines persists, and the market continues to fail pregnant individuals. There is a need for collective action from all relevant stakeholders to accelerate investment in the development of new or improved medicines for pregnancy-related conditions.

Trop2 regulates motility and lamellipodia formation in cultured fetal lung fibroblasts.

Proliferation and migration of fibroblasts are vital for fetal lung development. However, the regulatory mechanisms are poorly understood. We have previously shown that TROP2 gene expression is closely associated with fetal lung cell proliferation in vivo and that TROP2 knockdown decreases proliferation of fetal lung fibroblasts in culture. We hypothesized that the Trop2 protein also regulates the morphology and motility of fetal lung fibroblasts. Fibroblasts isolated from fetal rat lungs (gestational age embryonic day 19) adopted a myofibroblast-like morphology in culture. Trop2 protein was localized to lamellipodia. TROP2 siRNA significantly decreased: TROP2 mRNA levels by 77%, the proportion of cells containing Trop2 protein by 70%, and cell proliferation by 50%. TROP2 siRNA also decreased the degree of motility as determined by the number of gridlines that cells moved across (2.2 ± 0.2 vs. 3.2 ± 0.2; P < 0.001). TROP2 knockdown altered cell morphology, causing a notable absence of lamellipodia and abnormal localization of components of the cell migration apparatus, and it reduced phosphorylated ERK1 and ERK2 levels. In contrast, TROP2 overexpression significantly increased: TROP2 mRNA levels by 40-fold, cell proliferation by 40%, the proportion of cells that were motile by 20%, and the number of gridlines that cells moved across (2.1 ± 0.2 vs. 1.6 ± 0.1; P < 0.001). Our data suggest that Trop2 regulates cell proliferation and motility and that it does so by regulating the ERK pathway and several critical components of the cell migration apparatus.

Effect of antenatal corticosteroid administration-to-birth interval on maternal and newborn outcomes: a systematic review.

Background: Antenatal corticosteroids (ACS) are highly effective at improving outcomes for preterm newborns. Evidence suggests the benefits of ACS may vary with the time interval between administration-to-birth. However, the optimal ACS administration-to-birth interval is not yet known. In this systematic review, we synthesised available evidence on the relationship between ACS administration-to-birth interval and maternal and newborn outcomes. Methods: This review was registered with PROSPERO (CRD42021253379). We searched Medline, Embase, CINAHL, Cochrane Library, Global Index Medicus on 11 Nov 2022 with no date or language restrictions. Randomised and non-randomised studies of pregnant women receiving ACS for preterm birth where maternal and newborn outcomes were reported for different administration-to-birth intervals were eligible. Eligibility screening, data extraction and risk of bias assessment were performed by two authors independently. Fetal and neonatal outcomes included perinatal and neonatal mortality, preterm birth-related morbidity outcomes and mean birthweight. Maternal outcomes included chorioamnionitis, maternal mortality, endometritis, and maternal intensive care unit admission. Findings: Ten trials (4592 women; 5018 neonates), 45 cohort studies (at least 22,992 women; 30,974 neonates) and two case-control studies (355 women; 360 neonates) met the eligibility criteria. Across studies, 37 different time interval combinations were identified. There was considerable heterogeneity in included administration-to-birth intervals and populations. The odds of neonatal mortality, respiratory distress syndrome and intraventricular haemorrhage were associated with the ACS administration-to-birth interval. However, the interval associated with the greatest improvements in newborn outcomes was not consistent across studies. No reliable data were available for maternal outcomes, though odds of chorioamnionitis might be associated with longer intervals. Intepretation: An optimal ACS administration-to-birth interval likely exists, however variations in study design limit identification of this interval from available evidence. Future research should consider advanced analysis techniques such as individual patient data meta-analysis to identify which ACS administration-to-birth intervals are most beneficial, and how these benefits can be optimised for women and newborns. Funding: This study was conducted with funding support from the UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), Department of Sexual and Reproductive Health and Research (SRH), a co-sponsored programme executed by the World Health Organization.

Innovations in the prevention and treatment of postpartum hemorrhage: Analysis of a novel medicines development pipeline database.

BACKGROUND: A significant barrier to improving prevention and treatment of postpartum hemorrhage (PPH) is a lack of innovative medicines that meet the needs of women and providers, particularly those in low-and middle-income countries (LMICs). The Accelerating Innovation for Mothers (AIM) project established a new database of candidate medicines under development for five pregnancy-related conditions between 2000 and 2021. OBJECTIVE: To systematically identify and rank candidates for prevention and treatment of PPH. SEARCH STRATEGY: Adis Insight, Pharmaprojects, WHO ICTRP, PubMed, and grant databases were searched to develop the AIM database. SELECTION CRITERIA: AIM database was searched for candidates being evaluated for PPH prevention and treatment, regardless of phase. DATA COLLECTION AND ANALYSIS: Candidates were ranked as high, medium, or low potential based on prespecified criteria. Analysis was primarily descriptive, describing candidates and development potential. MAIN RESULTS: Of the 444 unique candidates, only 39 pertained to PPH. One was high potential (heat-stable/inhaled oxytocin) and three were medium potential (melatonin, vasopressin and dofetilide via nanoparticle delivery). CONCLUSION: The pipeline for new PPH medicines is concerningly limited, lacking diversity, and showing little evidence of novel technologies. Without significant investment in early-phase research, it is unlikely that new products will emerge.

Increased airway liquid volumes at birth impair cardiorespiratory function in preterm and near-term lambs.

Respiratory distress is relatively common in infants born at or near-term, particularly in infants delivered following elective cesarean section. The pathophysiology underlying respiratory distress at term has largely been explained by a failure to clear airway liquid, but recent physiological evidence has indicated that it results from elevated airway liquid at the onset of air-breathing. We have investigated the effect of elevated airway liquid volumes at birth on cardiorespiratory function in preterm and near-term lambs. Preterm (130 ± 0 days gestation, term ∼147 days gestation; n = 12) and near-term (139 ± 1 days gestation; n = 13) lambs were instrumented (to measure blood pressure, blood flow, and blood gas status) and, at delivery, airway liquid volumes were adjusted to mimic levels expected following vaginal delivery (Controls; ∼7 mL/kg) or elective cesarean section with no labor (elevated liquid (EL); 37 mL/kg). Lambs were delivered, mechanically ventilated, and monitored for blood gas status, oxygenation, ventilator requirements, blood flows (carotid artery and pulmonary artery), and blood pressure during the first few hours of life. Preterm and near-term EL lambs had poorer gas exchange and required greater ventilatory support to maintain adequate oxygenation. Pulmonary blood flow was reduced and carotid artery blood flow, mean arterial blood pressure, and heart rate were reduced in EL near-term but not preterm lambs. These data provide further evidence that greater airway liquid volumes at birth adversely affect newborn cardiorespiratory function, with the effects being greater in near-term newborns.NEW & NOTEWORTHY We provide evidence for adverse effects of elevated airway liquid volumes at birth on pulmonary blood flow and gas exchange in both preterm and near-term lambs, although the effects were greatest in near-term newborns. Our study is an important step toward understanding the fundamental physiology underlying the cardiorespiratory morbidity associated with near-term newborns with elevated airway liquid volumes leading to respiratory distress soon after birth.

The oncogene Trop2 regulates fetal lung cell proliferation.

The factors regulating growth of the developing lung are poorly understood, although the degree of fetal lung expansion is critical. The oncogene Trop2 (trophoblast antigen 2) is upregulated during accelerated fetal lung growth, and we hypothesized that it may regulate normal fetal lung growth. We investigated Trop2 expression in the fetal and neonatal sheep lung during accelerated and delayed lung growth induced by alterations in fetal lung expansion, as well as in response to glucocorticoids. Trop2 expression was measured using real-time PCR and localized spatially using in situ hybridization and immunofluorescence. During normal lung development, Trop2 expression was higher at 90 days gestational age (GA; 4.0 ± 0.8) than at 128 days GA (1.0 ± 0.1), decreased to 0.5 ± 0.1 at 142 days GA (full term ∼147 days GA), and was positively correlated to lung cell proliferation rates (r = 0.953, P < 0.005). Trop2 expression was regulated by fetal lung expansion, but not by glucocorticoids. It was increased nearly threefold by 36 h of increased fetal lung expansion (P < 0.05) and was reduced to ∼55% of control levels by reduced fetal lung expansion (P < 0.05). Trop2 expression was associated with lung cell proliferation during normal and altered lung growth, and the TROP2 protein colocalized with Ki-67-positive cells in the fetal lung. TROP2 was predominantly localized to fibroblasts and type II alveolar epithelial cells. Trop2 small interfering RNA decreased Trop2 expression by ∼75% in cultured fetal rat lung fibroblasts and decreased their proliferation by ∼50%. Cell viability was not affected. This study demonstrates that TROP2 regulates lung cell proliferation during development.

Glucocorticoid signalling drives reduced versican levels in the fetal mouse lung.

Glucocorticoid (GC) signaling via the glucocorticoid receptor (GR) is essential for lung maturation in mammals. Previous studies using global or conditional mouse model knockouts of the GR gene have established that GR-mediated signaling in the interstitial mesenchyme of the fetal lung is critical for normal lung development. Screens for downstream GC-targets in conditional mesenchymal GR deficient mouse lung (GRmesKO) identified Versican (Vcan), an important extracellular matrix component and cell proliferation regulator, as a potential GR-regulated target. We show that, of the five major VCAN isoforms, the VCAN-V1 isoform containing the GAGß domain is the predominant VCAN isoform in the fetal mouse lung distal mesenchyme at both E16.5 and E18.5, whereas the GAGα-specific VCAN-V2 isoform was only localized to the smooth muscle surrounding proximal airways. Both Vcan-V1 mRNA and protein levels were strongly overexpressed in the GRmesKO lung at E18.5. Finally, we investigated the GC regulation of the ECM protease ADAMTS 12 and showed that Adamts 12 mRNA levels were markedly reduced at E18.5 in GRmesKO fetal mouse lung and were strongly induced by both cortisol and betamethasone in cultures of primary rat fetal lung fibroblasts. ADAMTS12 protein immunoreactivity was also strongly increased in the distal lung at E18.5, after dexamethasone treatment in utero. In summary, glucocorticoid signaling via GR represses GAGß domain-containing VCAN isoforms in distal lung mesenchyme in vivo by repressing Vcan gene expression and, in part, by inducing the ECM protease ADAMTS12, thereby contributing to the control of ECM remodelling and lung cell proliferation prior to birth.

Identification of Betamethasone-Regulated Target Genes and Cell Pathways in Fetal Rat Lung Mesenchymal Fibroblasts.

Preterm birth is characterized by severe lung immaturity that is frequently treated antenatally or postnatally with the synthetic steroid betamethasone. The underlying cellular targets and pathways stimulated by betamethasone in the fetal lung are poorly defined. In this study, betamethasone was compared with corticosterone in steroid-treated primary cultures of fetal rat lung fibroblasts stimulated for 6 hours and analyzed by whole-cell transcriptome sequencing and glucocorticoid (GC) receptor (GR) chromatin immunoprecipitation sequencing (ChIP-Seq) analysis. Strikingly, betamethasone stimulated a much stronger transcriptional response compared with corticosterone for both induced and repressed genes. A total of 483 genes were significantly stimulated by betamethasone or corticosterone, with 476 stimulated by both steroids, indicating a strong overlap in regulation. Changes in mRNA levels were confirmed by quantitative PCR for eight induced and repressed target genes. Pathway analysis identified cell proliferation and cytoskeletal/cell matrix remodeling pathways as key processes regulated by both steroids. One target, transglutaminase 2 (Tgm2), was localized to fetal lung mesenchymal cells. Tgm2 mRNA and protein levels were strongly increased in fibroblasts by both steroids. Whole-genome GR ChIP-Seq analysis with betamethasone identified GC response element-binding sites close to the previously characterized GR target genes Per1, Dusp1, Fkbp5, and Sgk1 and near the genes identified by transcriptome sequencing encoding Crispld2, Tgm2, Hif3α, and Kdr, defining direct genomic induction of expression in fetal lung fibroblasts via the GR. These results demonstrate that betamethasone stimulates specific genes and cellular pathways controlling cell proliferation and extracellular matrix remodeling in lung mesenchymal fibroblasts, providing a basis for betamethasone's treatment efficacy in preterm birth.