Introduction: The shaping of the human intestinal microbiota starts during the intrauterine period and continues through the subsequent stages of extrauterine life. The microbiota plays a significant role in the predisposition and development of immune diseases, as well as various inflammatory processes. Importantly, the proper colonization of the fetal digestive system is influenced by maternal microbiota, the method of pregnancy completion and the further formation of the microbiota. In the subsequent stages of a child’s life, breastfeeding, diet and the use of antibiotics influence the state of eubiosis, which determines proper growth and development from the neonatal period to adulthood. The literature data suggest that there is evidence to confirm that the intestinal microbiota of the infant plays an important role in regulating the immune response associated with the development of allergic diseases. However, the identification of specific bacterial species in relation to specific types of reactions in allergic diseases is the basic problem. Background: The main aim of the review was to demonstrate the influence of the microbiota of the mother, fetus and newborn on the functioning of the immune system in the context of allergies and asthma. Methods: We reviewed and thoroughly analyzed the content of over 1000 articles and abstracts between the beginning of June and the end of August 2024. Over 150 articles were selected for the detailed study. Results: The selection was based on the PubMed National Library of Medicine search engine, using selected keywords: “the impact of intestinal microbiota on the development of immune diseases and asthma”, “intestinal microbiota and allergic diseases”, “the impact of intrauterine microbiota on the development of asthma”, “intrauterine microbiota and immune diseases”, “intrauterine microbiota and atopic dermatitis”, “intrauterine microbiota and food allergies”, “maternal microbiota”, “fetal microbiota” and “neonatal microbiota”. The above relationships constituted the main criteria for including articles in the analysis. Conclusions: In the present review, we showed a relationship between the proper maternal microbiota and the normal functioning of the fetal and neonatal immune system. The state of eubiosis with an adequate amount and diversity of microbiota is essential in preventing the development of immune and allergic diseases. The way the microbiota is shaped, resulting from the health-promoting behavior of pregnant women, the rational conduct of the medical staff and the proper performance of the diagnostic and therapeutic process, is necessary to maintain the health of the mother and the child. Therefore, an appropriate lifestyle, rational antibiotic therapy as well as the way of completing the pregnancy are indispensable in the prevention of the above conditions. At the same time, considering the intestinal microbiota of the newborn in relation to the genera and phyla of bacteria that have a potentially protective effect, it is worth noting that the use of suitable probiotics and prebiotics seems to contribute to the protective effect.

COVID-19 in pregnant women increases the risk of adverse pregnancy outcomes, including preeclampsia. This meta-analysis aimed to examine the effect of SARS-CoV-2 infection on sFlt-1/PIGF ratio during pregnancy. The study was designed as a systematic review and meta-analysis. PubMed, Web of Science, Embase and Cochrane Library were searched for relevant studies reporting the sFlt-1/PlGF ratio in pregnant women with COVID-19. Results were compared using meta-analysis by the Mantel–Haenszel method. A total of 7 studies were included in the analysis. sFlt-1/PlGF ratios between COVID-19 positive vs. negative women were 45.8 ± 50.3 vs. 37.4 ± 22.5, respectively (SMD = 1.76; 95% CI: 0.43 to 3.09; p = 0.01). sFlt-1/PlGF ratios between asymptomatic vs. symptomatic patients were 49.3 ± 35.7 vs. 37.1 ± 25.6 (SMD = 0.30; 95% CI: −0.35 to 0.95; p = 0.36). sFlt-1/PlGF ratio in non-severe group was 30.7 ± 56.5, compared to 64.7 ± 53.5 for severe patients (SMD = −1.88; 95% CI: −3.77 to 0.01; p = 0.05). sFlt-1/PlGF ratios in COVID-19 patients, with and without hypertensive disease of pregnancy, were 187.0 ± 121.8 vs. 21.6 ± 8.6, respectively (SMD = 2.46; 95% CI: 0.99 to 3.93; p = 0.001). Conclusions: Patients with COVID-19, as compared to patients without COVID-19, were characterized by higher sFlt-1/PlGF ratio. Moreover, severe COVID-19 and SARS-CoV-2 infection in hypertensive pregnant women was related to significantly higher sFlt-1/PlGF ratio.

Mechanisms resulting from the physiological immaturity of the digestive system in children delivered before 32 weeks of gestation and, in particular, different interactions between the microbiome and the body have not been fully elucidated yet. Next-generation sequencing methods demonstrated the presence of bacterial DNA in the placenta and amniotic fluid, which may reflect bacterial populations that initiate intestinal colonization in utero. Numerous studies confirmed the hypothesis stating that intestinal bacteria played an important role in the pathogenesis of necrotizing enterocolitis (NEC) early- and late-onset neonatal sepsis (EONS and LONS). The model and scale of disorders within the intestinal microbiome are the subject of active research in premature infants. Neonatal meconium was primarily used as an indicator defining the environment in utero, as it is formed before birth. Metagenomic results and previous data from microbiological bacterial cultures showed a correlation between the time from birth to sample collection and the detection of bacteria in the neonatal meconium. Therefore, it may be determined that the colonization of the newborn’s intestines is influenced by numerous factors, which may be divided into prenatal, perinatal, and postnatal, with particular emphasis put on the mode of delivery and contact with the parent immediately after birth. Background: The aim of this review was to collect available data on the intrauterine shaping of the fetal microbiota. Methods: On 13 March 2024, the available literature in the PubMed National Library of Medicine search engine was reviewed using the following selected keywords: “placental microbiome”, “intestinal bacteria in newborns and premature infants”, and “intrauterine microbiota”. Results: After reviewing the available articles and abstracts and an in-depth analysis of their content, over 100 articles were selected for detailed elaboration. We focused on the origin of microorganisms shaping the microbiota of newborns. We also described the types of bacteria that made up the intrauterine microbiota and the intestinal microbiota of newborns. Conclusions: The data presented in the review on the microbiome of both term newborns and those with a body weight below 1200 g indicate a possible intrauterine colonization of the fetus depending on the duration of pregnancy. The colonization occurs both via the vaginal and intestinal route (hematogenous route). However, there are differences in the demonstrated representatives of various types of bacteria, phyla Firmicutes and Actinobacteria in particular, taking account of the distribution in their abundance in the individual groups of pregnancy duration. Simultaneously, the distribution of the phyla Actinobacteria and Proteobacteria is consistent. Considering the duration of pregnancy, it may also be concluded that the bacterial flora of vaginal origin dominates in preterm newborns, while the flora of intestinal origin dominates in term newborns. This might explain the role of bacterial and infectious factors in inducing premature birth with the rupture of fetal membranes.

Background: Neonatal sepsis is a bloodstream infection and constitutes a major cause of morbidity and mortality among newborns. The diagnosis is primarily based on a positive blood culture result. An additional diagnostic and therapeutic challenge may be congenital infection, particularly in preterm infants. This is associated with the lack of routine screening of the maternal genital tract, except for testing for group B streptococci during earlier stages of an uncomplicated pregnancy. Case presentation: This paper presents a case of a neonate with early-onset sepsis (EONS) caused by Escherichia coli. Methods: We carried out analysis of documents combined with the case report method. Results: Preterm birth associated with PPROM constitutes a significant risk factor for early-onset neonatal sepsis (EONS). Conclusions: The case illustrates the dynamic course of congenital infection and the resulting need for immediate, life-saving interventions. It also demonstrates abnormalities identified in ancillary investigations involving both the visual system and the central nervous system (CNS), confirming the intrauterine onset of the infectious process.

Background: Persistent pulmonary hypertension of the newborn (PPHN) remains a life-threatening condition resulting from failure of postnatal circulatory adaptation. Inhaled nitric oxide (iNO) is the standard first-line therapy; however, limited access or inadequate response highlight the need for alternative treatments. Milrinone, a selective phosphodiesterase-3 inhibitor with nitric oxide-independent vasodilatory and inotropic properties, has been proposed as one such option. Methods: In this study we present a case series of three neonates with PPHN—term (41 weeks), late preterm (35 weeks), and extremely preterm (23 weeks)—treated with intravenous milrinone in a neonatal unit without immediate access to iNO. A narrative literature review was also conducted, focusing on clinical outcomes, safety, and therapeutic applicability. Results: Milrinone was initiated within the first 24 h of life. In the term and late-preterm infants, oxygenation and echocardiographic parameters improved within 48 h, with normalization of shunt direction and successful extubation by days 4–10. Transient systemic hypotension occurred in both cases and required dose adjustment or vasoactive support. In the extremely preterm neonate, only temporary hemodynamic improvement was achieved, followed by severe intraventricular hemorrhage and coagulopathy, possibly exacerbated by vasodilatory and antiplatelet effects of milrinone. Conclusions: Milrinone may serve as a feasible adjunct or bridging therapy for PPHN when iNO is unavailable. However, its use requires careful hemodynamic and neurological monitoring, particularly in very preterm infants. Further studies are needed to confirm safety and define optimal dosing across gestational ages.

This manuscript presents a comprehensive narrative review of the applications of polysomnography in infants. Considering the growing interest in the early identification of sleep-disordered breathing and its impact on the development of the nervous system, this is an exceptionally important and clinically relevant topic. There is a significant need for a proper understanding of the concept of polysomnography, which would enable its appropriate use in both diagnosis and treatment. This issue becomes particularly important given the limited number of scientific reports addressing the neonatal and infant periods. Objective: The usefulness of polysomnography during the first year of a child’s life. Methods: Between February and August 2025, a review of publications presenting aspects of polysomnography was conducted. Special attention was given to studies concerning the infant period, published between January 2015 and January 2025. The selection was carried out through the PubMed National Library of Medicine search engine, using the following keywords: “polysomnography”, “obstructive sleep apnea”, and “infant.” Results: Based on detailed inclusion criteria, 90 out of 1200 publications were qualified for analysis. Conclusions: Polysomnography is used both in the diagnostic process and in qualification for surgical treatment. It enables actions aimed at multidisciplinary management that improve patient outcomes while simultaneously reducing factors that worsen prognosis. At the same time, its usefulness in evaluating the therapeutic process and assessing improvement after both noninvasive and invasive interventions should be emphasized.