Background: The maternal microbiota serve as a key regulator of neonatal immune development and early-life health outcomes. This systematic review aims to find out how the makeup of the maternal microbiota affects newborn immunity and the risk of allergies, identify which microbes are linked to a higher or lower chance of allergies, and assess treatments that could improve newborn immune health. Methods: We conducted a systematic search in PubMed, MEDLINE, and Web of Science, adhering to the PRISMA guidelines. We included randomized controlled trials (RCTs), cohort studies, and observational studies that looked at how the makeup of the maternal microbiota affects newborn immune responses or allergic outcomes in early life. We conducted a systematic search, and the quality of the studies was evaluated using the GRADE system and tools to check for bias (RoB 2, Newcastle–Ottawa Scale, MINORS). Results: We included a total of 74 studies. The main findings showed that having a cesarean delivery and using certain antibiotics during pregnancy increased the risk of allergies, while breastfeeding, taking probiotics, and changing the mother’s diet helped to protect against allergies. Maternal stress had a negative association with the microbiota composition (OR = 1.9–2.4) and neonatal immune regulation. Moreover, the study noted significant geographic variation in the microbiota’s influence, underscoring the importance of contextualized interventions. Conclusions: The composition of the maternal microbiota has a major impact on neonatal immunity and the risk of early-life allergy. Adverse factors include cesarean birth, antibiotic exposure, and maternal stress, all of which have been associated with alterations in neonatal immunity. More studies are required to validate promising microbiota-targeted strategies and develop evidence-based guidelines to improve maternal and neonatal immune health.

Inguinal hernia repair (IHR) is a common surgical procedure among neonates and infants; the time of surgery is one of the major factors affecting its outcomes. Our systematic review aims to evaluate the effects of surgical timing on outcomes in inguinal hernia repairs in the newborn and infant population to establish evidence-based guidelines for optimal surgical timing. A systematic search was performed in PubMed, MEDLINE, and Web of Science databases, following PRISMA guidelines. Studies evaluating neonates and infants undergoing IHR with outcomes of recurrence, complications, and postoperative recovery were included. Data were collaboratively extracted, including patient demographics, surgical approaches, perioperative complications, and long-term outcomes. Early repair (0–28 days of life) decreased the risk of hernia incarceration but also increased the risk of preoperative complications. Delayed repair (29 days to 1 year of life) showed fewer preoperative complications but increased the risk of incarceration. The outcomes were affected by variables including patient maturity and comorbidities, along with hernia severity. Neonates with a high risk for incarceration are best treated with early repair, while stable infants can be managed safely with delayed repair. More randomized trials are needed to develop standardized guidelines that balance the associated risks of neonatal versus infant repair strategies to maximize benefits.