Bronchopulmonary dysplasia (BPD) is the most common serious complication of very preterm infants (VPI) or very low birth weight (VLBW) infants. Studies implicate viral infections in etiopathogenesis. The aim of this study was to summarize the relationship between viral infections and BPD through a systematic review and meta-analysis. We searched PubMed, Embase, the Web of Science Core Collection, and the Cochrane Database on December 19, 2023. We included observational studies that examined the association between viral infections and BPD in preterm infants. We extracted data on study methods, participant characteristics, exposure assessment, and outcome measures. We assessed study risk of bias using the Newcastle-Ottawa Scale (NOS). We included 17 and 15 studies in the qualitative review and meta-analysis, respectively. The meta-analysis showed a significant association between viral infection and BPD diagnosed at 36 weeks postmenstrual age (odds ratio (OR): 2.42, 95% confidence interval: 1.89–3.09, 13 studies, very low certainty of evidence). In a subgroup analysis of specific viruses, cytomegalovirus (CMV) proved to be significantly associated with BPD diagnosed at 36 weeks postmenstrual age (OR: 2.34, 95% confidence interval: 1.80–3.05, 11 studies). We did not find an association between viral infection and BPD diagnosed on the 28th day of life, probably due to the small sample size of the included prospective studies.  Conclusion: Viral infections, especially CMV, are associated with an increased risk of BPD in preterm infants. Methodologically reliable prospective studies with large samples are needed to validate our conclusions, and high-quality randomized controlled studies are needed to explore the effect of prevention or treatment of viral infections on the incidence of BPD. What is Known:• Studies have attempted to identify viral infections and bronchopulmonary dysplasia in preterm infants; however, results have been inconsistent. What is New:• Systematic demonstration that viral infections, particularly cytomegalovirus, are positively associated with bronchopulmonary dysplasia diagnosed in preterm infants at the 36th week of postmenstrual age.• The importance of screening for viral infections in preterm infants, especially cytomegalovirus. More high-quality studies should be produced in the future to investigate the causal relationship between viral infections and bronchopulmonary dysplasia.

Introduction Necrotising enterocolitis (NEC) of the intestine of preterm infants leads to the risk of abdominal surgery, short bowel syndrome, neurodevelopmental disorders and death. Although the risks of NEC and its complications have been recognised in many countries, few countries have established NEC-specific registries to continuously monitor its aetiology and prognosis. In China, the understanding of risk factors and prognosis of NEC is incomplete, characterised by a lack of evidence from prospective and multicentre studies. Therefore, we designed a multicentre, prospective, open observational cohort study with the aim of investigating the risk factors and prognosis of NEC in a real-world setting in Shenzhen, Guangdong Province, by constructing an online registry of children with NEC and a bank of biospecimens. Methods This is a prospective, multicentre, open observational cohort study. From June 2024 to June 2028, more than 600 patients with NEC from 15 tertiary hospitals in Shenzhen, Guangdong Province, will be enrolled in the study. By constructing an online registry for NEC, clinical data will be collected during the prenatal and hospitalisation periods. Prospectively, biospecimens will be collected during the period of suspected NEC, at the time of confirmed NEC, and at the time of confirmed severe NEC, and filed in the online registry system. Follow-up data will include postdischarge healthcare needs, growth patterns measures, eye or vision examinations, cranial MRI findings, brainstem auditory evoked potentials or automated auditory brainstem responses, and the Chinese Griffith Developmental Scale at corrected age 18–24 months. Follow-up results were likewise recorded in an online registry system. Hospitalisation outcomes, including severe NEC, somatic growth and survival status, will be collected at discharge. Follow-up outcomes will include loss to visit, survival status, somatic growth measures and severe neurodevelopmental deficits at corrected age 18–24 months. This study will enhance our overall understanding of the risk factors and outcomes of NEC, ultimately helping to reduce the incidence of neonatal NEC and its poor prognosis. Ethics and dissemination Our programme has received approval from the Ethics Committee for Scientific Research Projects of the Longgang District Maternity & Child Healthcare Hospital in Shenzhen City (ethics approval number: LGFYKYXMLL-2024-47-01). We anticipate presenting our findings at various national conferences and submitting them to peer-reviewed paediatrics journals. Trial registration number ChiCTR2400085043.

Introduction Bronchopulmonary dysplasia (BPD) in very preterm infants (VPIs) has adverse long-term outcomes and affects the quality of survival. There are no registry studies on BPD in VPIs in China. Our aim was to conduct a prospective, multicentre, open, longitudinal, observational cohort study to investigate the epidemiological characteristics, diagnosis, treatment, and short-term and long-term outcomes of BPD in a real-life setting in China and lay the grounds for establishing a nationwide registry with clinical data and biological specimens. Methods This study aims to recruit a minimum of 2000 VPIs and start research in January 2024 in Shenzhen, China. We will collect clinical data from the beginning of the life of VPIs and follow them up to 3 years old. Short-term outcomes, such as the incidence of BPD, necrotising enterocolitis, retinopathy of prematurity, intraventricular haemorrhage and porencephalic ventricular leukomalacia, as well as the cost of hospitalisation, are the major variables of concern. Bayley-III Scale assessment, gross motor function and pulmonary function evaluation will be performed at the age of correction, that is, 18–24 months and 30–36 months. The follow-up outcomes include loss to follow-up, survival status, moderate-to-severe neurodevelopmental deficits and severe respiratory complications. Cord blood, peripheral blood, tracheal aspirate, faeces and urine from VPIs, as well as mother’s milk, will be collected and stored at −80°C. All the data will be registered, stored and managed in a cloud-based database. This knowledge will be useful for establishing diagnostic criteria and predictive models for BPD in the Chinese population. Ethics and dissemination Our protocol has been approved by the Medical Ethics Committee of Shenzhen People’s Hospital (LL-KY-2023174-02) and the local ethics committee of each participating centre. Our goal is to present our findings at national conferences and in peer-reviewed paediatric journals. Trial registration number Chinese Clinical Trial Registry (ChiCTR2400081615).

Introduction Bronchopulmonary dysplasia (BPD) is one of the most common and significant complications of preterm birth. It ultimately leads to a decrease in the quality of life for preterm infants and impacts their long-term health. Early prediction and timely intervention are crucial to halting the development of BPD. This study aims to identify the biomarkers that can predict the early occurrence and development of BPD by screening serum metabolites in preterm infants. This will provide strong support for the early prediction of BPD and targeted interventions in future research. Methods and analysis This is a prospective, multicentre, open-label, observational cohort study spanning 3 years. It will be conducted in six major neonatal intensive care units in Shenzhen, China, involving preterm infants born at gestational ages <32 weeks. Demographic data and treatment information will be collected prospectively. Serum samples will be collected at five distinct time points: within 24 hours after birth, at 1 week, 2 weeks, 28 days and at 36 weeks postmenstrual age. These samples will undergo analysis using liquid chromatography-tandem mass spectrometry for untargeted metabolomics studies. Participants will be categorised into BPD and non-BPD groups based on their final diagnosis, and metabolite differences between these groups will be analysed. The study aims to enrol 1500 preterm infants with gestational ages <32 weeks over 3 years. A three-step analysis strategy—discovery, validation and clinical testing—will be used to identify and validate the clinical utility of novel biomarkers. Additionally, a nested case-control study will be conducted, matching participants 1:1 with a control group sharing similar BPD risk factors. Ethics and dissemination Our protocol has been approved by the Medical Ethics Committees of all participating hospitals, including Peking University Shenzhen Hospital, Shenzhen People’s Hospital, Shenzhen Baoan Women’s and Children’s Hospital, Longgang District Maternity and Child Healthcare Hospital, Nanshan Maternity and Child Healthcare Hospital and Shenzhen Luohu People’s Hospital. We will disseminate our study results through academic conferences and peer-reviewed public journals. Trial registration number ChiCTR2400081615.

Introduction: Hypoxic-ischaemic encephalopathy (HIE), a leading cause of neurological disability in neonates, is managed with therapeutic hypothermia, yet systematic data on its aetiology and prognosis are lacking, particularly in China. Herein, our study addresses this gap by establishing a prospective registry in Shenzhen and aims to clinically characterise HIE, identify its risk factors and document its long-term outcomes. Methods and analysis: We will recruit 200 neonates with HIE from 10 hospitals in Shenzhen, China, between January 2025 and December 2028. In parallel, clinical data will be collected during hospitalisation, with supplemental referral information obtained from birth hospitals via an online, specialised HIE database. We will include HIE severity, survival status and the incidence of serious complications, such as arrhythmias, pulmonary haemorrhage, neonatal acute respiratory distress syndrome, persistent pulmonary hypertension of the newborn and disseminated intravascular coagulation, to assess key outcomes of HIE in neonates. Longitudinal follow-up is scheduled for 18, 24 and 36 months, involving assessments using physical developmental scales, video-electroencephalogram (VEEG) recordings, the Chinese version of the Bayley Infant and Toddler Developmental Scale, Fourth Edition and cranial MRI at 18 months. The primary objectives of this study are to determine survival status, track loss-to-follow-up rates and evaluate neurodevelopmental outcomes at 3 years, with the ultimate goal of enhancing our understanding of HIE risk factors, hypothermia therapy and prognosis to reduce HIE-related morbidity and disability. Ethics and dissemination: This study protocol has been approved by the Medical Ethics Committee of Shenzhen Children’s Hospital (Ethics No. 2024096), and the findings will be disseminated through presentations at national academic conferences and publication in peer-reviewed paediatric journals. Trial registration number: ChiCTR2400094994.