Neuromuscular maturation in the neonate: Combined electroneurographic and ultrasonographic study

Impact of preterm birth on muscle mass and function: a systematic review and meta-analysis

Individuals born preterm present lower exercise capacity. Along with the cardiopulmonary responses and activity level, muscle strength is a key determinant of exercise capacity. This systematic review aimed to summarize the current knowledge on the impact of preterm birth on skeletal muscle mass and function across the lifespan. The databases PubMed, MEDLINE, EBM, Embase, CINAHL Plus, Global Index Medicus, and Google Scholar were searched using keywords and MeSH terms related to skeletal muscle, preterm birth, and low birth weight. Two independent reviewers undertook study selection, data extraction, and quality appraisal using Covidence review management. Data were pooled to estimate the prematurity effect on muscle mass and function using the R software. From 4378 studies retrieved, 132 were full-text reviewed and 25 met the inclusion/exclusion criteria. Five studies presented a low risk of bias, and 5 had a higher risk of bias due to a lack of adjustment for confounding factors and presenting incomplete outcomes. Meta-analyses of pooled data from homogenous studies indicated a significant reduction in muscle thickness and jump test (muscle power) in individuals born preterm versus full-term with standardized mean difference and confidence interval of - 0.58 (0.27, 0.89) and - 0.45 (0.21, 0.69), respectively.    Conclusion: Overall, this systematic review summarizing the existing literature on the impact of preterm birth on skeletal muscle indicates emerging evidence that individuals born preterm, display alteration in the development of their skeletal muscle mass and function. This work also highlights a clear knowledge gap in understanding the effect of preterm birth on skeletal muscle development. What is Known: • Preterm birth, which occurs at a critical time of skeletal muscle development and maturation, impairs the development of different organs and tissues leading to a higher risk of comorbidities such as cardiovascular diseases. • Preterm birth is associated with reduced exercise capacity. What is New: • Individuals born preterm display alterations in muscle mass and function compared to individuals born at term from infancy to adulthood. • There is a need to develop preventive or curative interventions to improve skeletal muscle health in preterm-born individuals.

Using ultrasound to examine muscle mass in preterm infants at term-equivalent age

The aim of this study was to compare the skeletal muscle thickness of three different muscles and muscle groups in 44 preterm infants studied at term-equivalent age and 44 full-term controls: the biceps brachii, quadriceps femoris, and anterior tibial. The study was carried out at the Careggi University Hospital, Florence, Italy, from January 2018 to December 2019. We assumed that impaired muscle thickness in premature infants would be correlated with exposure to risk factors in the postnatal period. When the premature babies reached term-equivalent age, they were statistically significantly thinner and shorter and had a lower head circumference and lower body mass index than the full-term controls. The muscle thicknesses in the proximal and distal districts were statistically significantly smaller in prematurely born than term-born infants. The skeletal muscle thickness was related to the revised Clinical Risk Index for Babies score and days of invasive mechanical ventilation.Conclusion: Our data show that at term-equivalent age the premature babies had lower skeletal muscle mass acquisition than the full-term controls. This was particularly due to critical conditions at birth and the subsequent duration of invasive mechanical ventilation. What is Known: • The deleterious effects of prolonged mechanical ventilation on skeletal muscle function have been reported by adult intensive care studies. • Ultrasound imagines of fat and muscle thickness have been used in neonatology, as the method is safe, portable, and noninvasive. What is New: • Premature babies studied at term-equivalent age had lower muscle acquisition, but similar subcutaneous fat thickness, to full-term controls. • A high revised Clinical Risk Index for Babies score at birth, and prolonged invasive mechanical ventilation, was associated with skeletal muscle impairment.