Effects of in-hospital breast feeding on brain function development in preterm infants in China: study protocol for a prospective longitudinal cohort study

The Utilization of Sodium Concentration in Human Milk from Pump-Dependent Mothers of Preterm Infants as a Measure of Milk Production

Objective: This study investigated changes in sodium concentrations in human milk from mothers of premature infants using different breast pumps for 14 days postpartum, and the correlation between the sodium concentration in mother's own milk (MOM) and the volume pumped. Study Design: This randomized controlled study recruited 66 mothers of premature infants delivered in our hospital from February to December 2018, and we assigned them to three groups using an envelope method. In intervention group 1, a hospital-grade electric breast pump was used from postpartum day 1 to 14; in intervention group 2, a hospital-grade electric breast pump was used on postpartum days 1 to 5 and a normal personal electric breast pump on postpartum days 6 to 14; in the control group, a personal normal electric breast pump was used from postpartum day 1 to 14. Data recorded included the breast milk volume pumped and milk sodium concentration. Results: The average daily volume of MOM pumped differed statistically (p < 0.05) between the intervention and control groups at postpartum days 7 and 14. The average daily volume pumped did not differ between intervention groups 1 and 2 by postpartum day 14 (p > 0.05). However, the time taken for the sodium concentrations to normalize differed significantly (p < 0.01). At postpartum day 5, the sodium concentrations of 73% of intervention group 1 and 2 mothers were within normal limits, and they were maintained until day 14. In comparison, only 41% of the controls had normal MOM sodium levels on day 5, and they were still high on day 7 in 27.3% of controls. Conclusions: In the early stage of lactation initiation (within 5 days postpartum), using a hospital-grade electric breast pump promotes lactation in mothers who deliver prematurely and the sodium concentrations normalize more quickly. Sodium can be used as an objective biomarker of MOM to evaluate the possibility of delayed lactation in mothers of premature infants, and it could assist interventions in the early postpartum period. Trial Registration: Chinese Clinical Trial Registry, ChiCTR2200061384.

Early biomarkers of neurodevelopmental disorders in preterm infants: protocol for a longitudinal cohort study

INTRODUCTION

Preterm (PT) infants are at high likelihood for poor neurodevelopmental outcomes, including autism spectrum disorder (ASD), attention-deficit hyperactivity disorder (ADHD) and other neurodevelopmental disorders (NDDs), which could considerably impair the individuals' functions throughout their whole life. The current cohort study aims to investigate adverse outcomes, especially NDDs, in PT children, and the related early aberrant brain developmental biomarkers.

METHODS AND ANALYSIS

This is a prospective cohort study in Beijing, China. We plan to recruit 400 PT infants born at <37 weeks of gestational age (GA), and 200 full-term (FT) controls during the neonatal period (40 weeks corrected GA), then follow them up until they reach 6 years of age. This cohort is designed to assess neuropsychological functions, brain development, related environmental risk factors and the incidence of NDDs by using the following measures: (1) social, emotional, cognitive and sensorimotor functions; (2) MRI, electroencephalogram and functional near-infrared spectroscopy; (3) social economic status, maternal mental health and DNA methylation; and (4) symptoms and diagnosis of NDDs. Main data analyses will include comparing the neurodevelopment outcomes and brain developmental trajectories between PT and FT children using linear or logistic regressions and mixed-effects models. Regression analyses and machine learning will be used to identify early biological predictors and environmental risk or protective factors for later NDDs outcomes.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the research ethics committee of Peking University Third Hospital (M2021087). This study is under review in the Chinese Clinical Trial Register. The study results from the current cohort will be disseminated and popularised through social media to participating parents, as well as parents who are giving care to PT children.

Investigation Into the Current Situation and Analysis of the Factors Influencing Extrauterine Growth Retardation in Preterm Infants

Objective: This study aims to explore the occurrence of extrauterine growth retardation (EUGR) in preterm infants with a gestational age of <34 weeks, at discharge, and the factors influencing the occurrence of EUGR. Method: A retrospective analysis of 691 preterm infants with a gestational age of less than 34 weeks, born in our hospital over the past 3 years. At discharge, the growth indicators head circumference, weight, and length were used to divide the infants into an EUGR group (n = 255) and the non-EUGR group (n = 436). The occurrence of EUGR and its influencing factors were then analyzed. Results: Of the 691 preterm infants evaluated for inclusion in the study, 255 cases (36.9%) met the requirements of EUGR at discharge. The different growth indicators used, i.e., weight, length, and head circumference, classified the infants differently. The incidence of EUGR using these measures was 30.2% (209), 27.9% (193), and 23.2% (161), respectively. The results of a univariate analysis showed that gestational age, birth weight, intrauterine growth retardation (IUGR), maternal gestational hypertension, age at which the infant commenced feeding, duration of the application of an invasive ventilator, length of hospital stay, nosocomial infection, respiratory and gastrointestinal diseases, symptomatic patent ductus arteriosus, and the early onset of neonatal sepsis were correlated with the occurrence of EUGR. Further logistic multivariate regression analysis revealed that low gestational age, low birth weight, complicated IUGR, respiratory distress syndrome, and necrotizing enterocolitis were independent risk factors for EUGR in preterm infants with a gestational age <34 weeks. Conclusion: In preterm infants with a gestational age <34 weeks in our hospital, there is a high incidence of EUGR, which is affected by factors such as the gestational age, birth weight, IUGR, respiratory distress syndrome, necrotizing enterocolitis, and other factors.