Search Results (130)

To assess the association between known (PlGF, sFlt-1, betaHCG, PAPPA) and novel (cell-free DNA, cfDNA, and total endothelial and platelet microvesicles, MVs) maternal blood biomarkers measured at the first trimester with the later development of preeclampsia (PE) and PE-related severe adverse events (SAE), we conducted a retrospective case–control study including women with an established diagnosis of preeclampsia (cases) and healthy pregnant women (controls). Biomarkers were measured from first-trimester blood samples stored in a hospital biobank. A total of 89 women, 54 women with PE and 35 controls were included. PlGF showed good performance for diagnosing overall preeclampsia (AUC: 0.71; 95% CI 0.59–0.82), early-onset preeclampsia (AUC 0.80; 95% CI 0.68–0.9) and fetal-neonatal SAEs (AUC: 0.73; 95% CI 0.63–0.84). Multivariate models including clinical variables, PlGF and other biomarkers showed good to very good discrimination for the development of PE, early-onset PE and fetal-neonatal SAEs (AUCs of 0.87, 0.89 and 0.79, respectively). Platelet-derived MVs were the best isolated biomarker for late-onset PE and, combined with systolic blood pressure, showed good discrimination (AUC: 0.81; 95% CI 0.71–0.92). For maternal SAEs, a model incorporating cfDNA and sFlt-1 provided excellent discrimination (AUC 0.92; 95% CI 0.82–1.00). Our findings suggest that multivariate models incorporating both clinical variables and first-trimester biomarkers may improve risk stratification for PE, especially for late-onset PE and for identifying women at risk of severe maternal or fetal complications. Notably, the inclusion of novel biomarkers such as cfDNA and MVs added value in clinical scenarios where the predictive performance of existing tools remains suboptimal. Full article

Preeclampsia (PE) is one of the main causes of obstetric complications and leads to both maternal and neonatal mortality. The maternal innate immune system plays an important role throughout pregnancy by providing protection against pathogens, while simultaneously inducing tolerance to a semi-allogenic developing fetus and placental development. Background/Objectives: To conduct a comparative study of immunological markers in the blood and placenta in preeclampsia. Methods: A total of 35 pregnant women were enrolled in a comparative study with preeclampsia (7) and with physiological pregnancy (28). A study of the immune status in peripheral blood and placenta was conducted with an examination of the subpopulation of lymphocytes profile and intracellular cytokines production by flow cytometry. Results: In the blood of pregnant women with PE, there was a decrease in CD14+ monocytes, as well as a significant increase of natural killers CD16+, CD56+ and activation markers HLA-DR+ and CD95+, as well as a significant rise in production of IL-10, TNF, Perforin, GM-CSF, and IGF. At the same time, in placental tissue in patients with preeclampsia, on the contrary, a significant decrease in regulatory cells CD4+, CD8+, CD14+, CD56+, CD59+, activation markers CD95+, as well as anti-inflammatory cytokine IL-10, growth factors VEGFR and IGF was detected. Conclusions: The maternal–fetal immune profile is crucial for successful fetal development and dysregulation of T-, B-, and NK cells can contribute to inflammation, oxidative stress, and the development of preeclampsia. Full article

Background/Objective: Early pregnancy loss is often caused by chromosomal abnormalities, necessitating accurate diagnostic tools. While product of conception (POC) chromosomal testing is commonly used, it can be limited by culture failure or an inability to obtain fetal tissue due to spontaneous expulsion. Cell-free fetal DNA (cff DNA) analysis provides a non-invasive alternative; however, its effectiveness in early pregnancy loss, particularly in cases where fetal components are still minimal, has not been fully established. The objective of this study was to evaluate the accuracy of pre- and postoperative cff DNA analysis for detecting fetal aneuploidy by comparing the results to those of POC chromosomal testing. Methods: In this single-center prospective cohort study, 50 women undergoing manual vacuum aspiration for pregnancy loss before 12 weeks of gestation were enrolled (February 2022–December 2024). Cff DNA analysis was performed on maternal blood samples collected pre- and postoperatively. The primary outcome was concordance between the cff DNA and POC results. Sensitivity, specificity, and factors affecting concordance were also assessed. Results: Eight participants were excluded due to unsuccessful POC culture (n = 3), suspected maternal tissue contamination in the POC sample (n = 1), mosaicism (n = 3), or triploidy (n = 1), resulting in 42 evaluable cases. Preoperative cff DNA analysis showed 88.1% concordance with POC (sensitivity 86.4% and specificity 90.0%). Postoperative analysis showed 78.6% concordance (sensitivity 72.7% and specificity 85.0%). Conclusions: The Cff DNA analysis of preoperative and postoperative maternal blood samples showed generally good concordance with conventional POC chromosomal testing in detecting fetal aneuploidy in early pregnancy loss. Full article

Maternal–fetal tolerance mechanisms are crucial during human pregnancy to prevent the immune rejection of the embryo. A well-known mechanism blocking NK-cell cytotoxicity is the interaction of their inhibitory killer-cell immunoglobulin-like receptors (iKIR) with HLA-C molecules on the target cells. In this study, we aimed to investigate the expression of iKIRs (KIR2DL1 and KIR2DL2/3) on the matched decidual and peripheral γδT cells and the localization of HLA-C ligands throughout human pregnancy. The degranulation of γδT cells of pregnant and non-pregnant women in the presence of trophoblast cells was evaluated as well. Our results showed a higher proportion of iKIR-positive γδT cells at the maternal–fetal interface early in human pregnancy compared to the paired blood of pregnant women and full-term pregnancy decidua. In accordance, HLA-C was intensively expressed by the intermediate cytotrophoblasts and decidua-invading extravillous trophoblasts (EVTs) in early but not late pregnancy. Decidual γδT cells during early pregnancy showed higher spontaneous degranulation compared to their blood pairs, but neither decidual nor peripheral γδ T cells increased their degranulation in the presence of Sw71 EVT-like cells. The latter were unable to suppress the higher cytotoxicity of γδT cells, suggesting a complex regulatory landscape beyond NK-like activity inhibition. Full article

Background: Lymphomas account for approximately 10% of cancers diagnosed during pregnancy, with Hodgkin’s lymphoma being the most common. However, non-Hodgkin lymphomas, including primary mediastinal large B-cell lymphoma (PMBCL), also represent a significant proportion. Both mediastinal lymphomas and pregnancy develop a hypercoagulable state, increasing the risk of venous thromboembolism and massive pulmonary embolism (PE), requiring extracorporeal membrane oxygenation (ECMO). Methods: Clinical data, blood test and imagings have been collected by the medical records of the patient. Results: We present a 25-year-old woman, at 32 weeks of gestation, who presented to the emergency department with progressive dyspnea and asthenia. Echocardiography revealed a hemodynamically significant pericardial effusion and severe right ventricular dysfunction. Given the severity of her condition, she underwent an emergency caesarean section and subsequently a pericardial drainage. A chest computed tomography scan revealed an incidental mediastinal mass along with a massive PE. Despite pericardial drainage, she remained hemodynamically unstable. Since thrombolysis was contraindicated for the recent cesarean section, venoarterial ECMO was initiated. Systemic anticoagulation was guaranteed by heparin, which shifted to argatroban for heparin resistance. The mediastinal mass was also biopsied, and the diagnosis of PMBCL carried out. Cytoreductive chemotherapy was initiated with the COMP-R regimen (i.e., cyclophosphamide, vincristine, methotrexate, prednisone, and rituximab), and the patient progressively improved up to ICU and hospital discharge. Conclusions: This case highlights the challenges in managing a complicated patient requiring early multidisciplinary intervention, which was crucial for stabilizing the patient and optimizing fetal and maternal prognosis. Full article

Background: The importance and etiology of meconium-stained amniotic fluid (MSAF) in preterm pregnancies are still poorly understood. Among other factors, intrauterine inflammation is proposed to be a pathophysiological change associated with MSAF. To study the extent of intrauterine inflammation, histological evaluation represents the “gold standard” of diagnostics. Objectives: To investigate the concomitant occurrence of MSAF and histological chorioamnionitis (HCA) and fetal inflammatory response (FIR). To investigate the incidence of short-term neonatal outcomes in preterm infants born from MSAF. Materials and methods: We conducted a single-center retrospective study in a tertiary neonatal intensive care unit between 2020 and 2022. 237 preterm infants born ≤ 32 weeks or with ≤1500 g birthweight were investigated. The group of infants born from MSAF was compared to the group of infants born from clear amniotic fluid (CAF). The variables measured were the following: HCA, FIR, maternal and fetal vascular malformations (MVM, FVM), maternal clinical and laboratory signs of chorioamnionitis (CA), early neonatal outcomes, neonatal white blood cell count (WBC) in the first day of life, and neonatal c-reactive protein (CRP) level on the second day of life. Histological evaluation of the placenta and the umbilical cord was based on the recommendation of the 2014 Amsterdam Placental Workshop Group Consensus Statement (APWGCS). Results: Out of 237 preterm infants (mean gestational age: 28.6 (95% CI: 28.2; 28.9) weeks, mean birth weight: 1165 (95% CI: 1110; 1218) grams), 22 were born from MSAF. There was no difference between the perinatal characteristics of the two groups. A higher incidence of HCA (54.5% vs. 32.6%; p: <0.001), a higher incidence of stage 3 HCA (45.4% vs. 9.3%), a higher incidence of FIR (50% vs. 16.7%; p: <0.001), and a higher incidence of stage 3 FIR (18.2% vs. 1.9%) were found in the MSAF group in comparison with the CAF group. A higher incidence of elevated (>30 mg/L) maternal CRP level (36.8% vs. 15.3%; p: 0.02) and elevated (>15 mg/L) neonatal CRP level (31.8% vs. 14.4%; p: 0.03) was detected in the MSAF group. Among neonatal complications, severe (Stage III/IV) intraventricular hemorrhage (IVH) had a higher incidence in the MSAF group (22.2% vs. 5.1%; p: 0.005). Conclusion: MSAF in preterm pregnancies is associated with a severe maternal and fetal inflammatory response in the placenta and the umbilical cord. MSAF is also accompanied by elevated systemic inflammatory parameters and a higher incidence of severe neonatal IVH as well. Full article

Vitamin B12 (cobalamin) plays a crucial role in neurodevelopment, particularly during pregnancy and early childhood. It is essential for DNA synthesis, red blood cell formation, and nervous system function. Maternal B12 levels are particularly important, as they influence fetal brain development. Inadequate maternal intake during pregnancy may lead to altered neurodevelopmental trajectories and increase the risk of ASD. Postnatally, insufficient dietary cobalamin in infants and young children could further contribute to cognitive and behavioral impairments. One potential mechanism linking low B12 levels to ASD involves its role in the gut microbiota balance. Dysbiosis, commonly observed in individuals with ASD, is associated with increased gut permeability, low-grade inflammation, and disruptions in the gut–brain axis, all of which may contribute to ASD symptoms. Additionally, B12 is essential for neurotransmitter metabolism, particularly in the synthesis of serotonin and dopamine, which regulate mood, cognition, and behavior. Cobalamin also plays a key role in neuronal myelination, which ensures efficient signal transmission in the nervous system. Disruptions in these processes could underlie some of the cognitive and behavioral features associated with ASD. Despite growing evidence, the link between B12 and ASD remains inconclusive due to inconsistent findings across studies. Research suggests that B12 levels may serve as a potential biomarker for disease progression and treatment response. However, many studies rely on single-time-point measurements, failing to account for individual variability, genetic predispositions, dietary intake, and environmental factors, all of which can influence B12 levels and ASD risk. Further longitudinal studies are needed to clarify this relationship. Full article

Backgrounds: Sickle cell anemia (SCA) is a multisystemic disorder that causes hemolytic anemia and impaired tissue perfusion due to sickling of red blood cells. Although there is a belief that adverse perinatal outcomes are frequent in pregnant women with SCA, this association has not been clearly established. The aim of this study was to compare the perinatal outcomes of women with homozygous mutated SCA who gave birth with those without the mutation. Methods: The study included 26 SCA patients with homozygous mutation and 108 pregnant women without mutation who gave birth in our center. Demographic and obstetric data, laboratory findings, and fetal findings of both groups were compared. Results: Statistically significant differences were found between the groups in terms of maternal age, body mass index (BMI), gravida, and parity (p ≤ 0.001, p = 0.035, p ≤ 0.001, p ≤ 0.001, respectively). Mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), red blood cell count (RBC), hemoglobin (Hb), and hematocrit (Hct) values were significantly lower in the SCA group. We also observed that more blood transfusions were performed during pregnancy and the postpartum period in the SCA group. Low birth weight, more neonatal intensive care unit admissions, and a higher cesarean section rate were present in the SCA group. During pregnancy, women with SCA were most frequently admitted to the hospital for acute painful crises. Preeclampsia was not more common in the SCA group. Conclusions: SCA carries serious risks for the mother and fetus during pregnancy. Therefore, the relationship between the disease and pregnancy requires more detailed research. Full article

Background/Objectives: Folate and B12, among other B vitamins, are methyl donors and contribute to multiple DNA methylation processes. Maternal deficiency of these nutrients may be associated with impaired fetal growth, affecting the nutritional status and adiposity of the newborn. This study aimed to describe maternal folate and B12 status throughout pregnancy and evaluate its association with neonatal nutritional status. Methods: We studied 90 healthy pregnant women and their babies from the prospective OBESO cohort (Mexico City). Serum folate and B12 concentrations were measured (ELISA) in the first and third trimesters of pregnancy. Deficiency was considered if serum folate was <4 ng/mL, red blood cell folate (RBC) < 151 ng/mL, active B12 < 40 pmol/L, and total B12 < 203 pg/mL). Maternal supplementation of these nutrients was recorded. Newborn assessment (24–72 h) included weight (BW), length (L), waist circumference (WC), and fat mass percentage (%FM; air-displacement plethysmography). Newborn nutritional status indexes were computed and interpreted (BMI/age and length/age) (term-WHO, preterm-Intergrowth). Mean differences, correlations, and multiple linear and logistic regressions were performed (SPSS v. 29). Results: One-third of women had total vitamin B12 deficiency at the end of pregnancy; no folate deficiency was observed. High doses for both folic acid and B12 supplementation were identified in the third trimester (2057.04 ± 2100.74 μg/d and 7.35 ± 4.56 μg/d). Higher first- and third-trimester maternal active B12 concentrations predicted higher WC and reduced the risk of LBW. Higher first-trimester Thcy levels increased the risk of stunting. Higher third-trimester total B12 and folate concentrations predicted higher WC; the latter was associated with higher FM% at birth. Conclusions: Maternal folate, B12, and Thcy levels influence newborn nutritional status alterations, including adiposity markers. It is vital to guarantee an optimal and balanced maternal B-complex status throughout pregnancy. Full article

Pregnancy involves significant immunological changes to support fetal development while protecting the mother from infections. A growing body of evidence supports the importance of immune checkpoint pathways, especially at the maternal–fetal interface, although limited information is available about the peripheral expression of these molecules by CD8+ and CD8− NK cell subsets during the trimesters of pregnancy. Understanding the dynamics of these immune cells and their checkpoint pathways is crucial for elucidating their roles in pregnancy maintenance and potential complications. This study aims to investigate the peripheral expression and functional characteristics of CD8+ and CD8− NK cell subsets throughout pregnancy, providing insights into their contributions to maternal and fetal health. A total of 34 healthy women were enrolled from the first, 30 from the second and 40 from the third trimester of pregnancy. At the same time, 35 healthy age-matched non-pregnant women formed the control group. From peripheral blood, mononuclear cells were separated and stored at −80 °C. CD8+ and CD8− NK cell subsets were analyzed from freshly thawed samples, and surface and intracellular staining was performed using flow cytometric analyses. The proportions of CD56+ NK cells in peripheral blood were similar across groups. While CD8− NKdim cells increased significantly in all trimesters compared to non-pregnant controls, CD8+ NKdim cells showed no significant changes. CD8− NKbright cells had higher frequencies throughout pregnancy, whereas CD8+ NKbright cells significantly increased only in the first and second trimesters. The expression levels of immune checkpoint molecules, such as PD-1 and PD-L1, and cytotoxic-activity-related molecules were stable, with notable perforin and granzyme B increases in CD8− NKbright cells throughout pregnancy. Our study shows that peripheral NK cell populations, especially CD8− subsets, are predominant during pregnancy. This shift suggests a crucial role for CD8− NK cells in balancing maternal immune tolerance and surveillance. The stable expression of immune checkpoint molecules indicates that other regulatory mechanisms may be at work. These findings enhance our understanding of peripheral immune dynamics in pregnancy and suggest that targeting CD8− NKbright cell functions could help manage pregnancy-related immune complications. This research elucidates the stable distribution and functional characteristics of peripheral NK cells during pregnancy, with CD8− subsets being more prevalent. The increased activity of CD8− NKbright cells suggests their critical role in maintaining immune surveillance. Our findings provide a basis for future studies to uncover the mechanisms regulating NK cell function in pregnancy, potentially leading to new treatments for immune-related pregnancy complications. Full article

(1) Background: Fetal chromosomal examination is a critical component of modern prenatal testing. Traditionally, maternal serum biomarkers such as free β-human chorionic gonadotropin (Free β-HCG) and pregnancy-associated plasma protein A (PAPPA) have been employed for screening, achieving a detection rate of approximately 90% for fetuses with Down syndrome, albeit with a false positive rate of 5%. While amniocentesis remains the gold standard for the prenatal diagnosis of chromosomal abnormalities, including Down syndrome and Edwards syndrome, its invasive nature carries a significant risk of complications, such as infection, preterm labor, or miscarriage, occurring at a rate of 7 per 1000 procedures. Beyond Down syndrome and Edwards syndrome, other chromosomal abnormalities, such as trisomy of chromosomes 9, 16, or Barr bodies, pose additional diagnostic challenges. Non-invasive prenatal testing (NIPT) has emerged as a powerful alternative for fetal genetic screening by leveraging maternal blood sampling. However, due to the extremely low abundance of fetal cells in maternal circulation, NIPT based on fetal cells faces substantial technical challenges. (2) Methods: Fetal nucleated red blood cells (FnRBCs) were first identified in maternal circulation in a landmark study published in The Lancet in 1959. Due to their fetal origin and presence in maternal peripheral blood, FnRBCs represent an ideal target for non-invasive prenatal testing (NIPT). In this study, we introduce a novel self-assembled cell array (SACA) chip system, a microfluidic-based platform designed to efficiently settle and align cells into a monolayer at the chip’s base within five minutes using lateral flow dynamics and gravity. This system is integrated with a fully automated, multi-channel fluorescence scanning module, enabling the real-time imaging and molecular profiling of fetal cells through fluorescence-tagged antibodies. By employing a combination of Hoechst+/CD71+/HbF+/CD45− markers, the platform achieves the precise enrichment and isolation of FnRBCs at the single-cell level from maternal peripheral blood. (3) Results: The SACA chip system effectively reduces the displacement of non-target cells by 31.2%, achieving a single-cell capture accuracy of 97.85%. This isolation and enrichment system for single cells is well suited for subsequent genetic analysis. Furthermore, the platform achieves a high purity of isolated cells, overcoming the concentration detection limit of short tandem repeat (STR) analysis, demonstrating its capability for reliable non-invasive prenatal testing. (4) Conclusions: This study demonstrates that the SACA chip, combined with an automated image positioning system, can efficiently isolate single fetal nucleated red blood cells (FnRBCs) from 50 million PBMCs in 2 mL of maternal blood, completing STR analysis within 120 min. With higher purification efficiency compared to existing NIPT methods, this platform shows great promise for prenatal diagnostics and potential applications in other clinical fields. Full article

Despite the increasing number of placenta accreta spectrum (PAS) cases in recent years, its impact on neonatal outcomes and respiratory morbidity, as well as the underlying pathogenetic mechanism, has not yet been extensively studied. Moreover, no study has yet demonstrated the effectiveness of antenatal corticosteroid therapy (CT) for the prevention of respiratory distress syndrome (RDS) in newborns of mothers with PAS at the molecular level. In this regard, microRNA (miRNA) profiling by small RNA deep sequencing and quantitative real-time PCR was performed on 160 blood plasma samples from preterm infants (gestational age: 33–36 weeks) and their mothers who had been diagnosed with or without PAS depending on the timing of the antenatal RDS prophylaxis. A significant increase in hsa-miR-199a-3p and hsa-miR-382-5p levels was observed in the blood plasma of the newborns from mothers with PAS compared to the control group. A clear trend toward the normalization of hsa-miR-199a-3p and hsa-miR-382-5p levels in the neonatal blood plasma of the PAS groups was observed when CT was administered within 14 days before delivery, but not beyond 14 days. Direct correlations were found among the hsa-miR-382-5p level in neonatal blood plasma and the hsa-miR-199a-3p level in the same sample (r = 0.49; p < 0.001), the oxygen requirements in the NICU (r = 0.41; p = 0.001), the duration of the NICU stay (r = 0.31; p = 0.019), and the severity of the newborn’s condition based on the NEOMOD scale (r = 0.36; p = 0.005). Logistic regression models based on the maternal plasma levels of hsa-miR-199a-3p and hsa-miR-382-5p predicted the need for cardiotonic therapy, invasive mechanical ventilation, or high-frequency oscillatory ventilation in newborns during the early neonatal period, with a sensitivity of 95–100%. According to the literary data, these miRNAs regulate fetal organogenesis via IGF-1, the formation of proper lung tissue architecture, surfactant synthesis in alveolar cells, and vascular tone. Full article

Background: SCUBE-1 (Signal peptide-CUB (complement C1r/C1s, Uegf, and Bmp1)-EGF (epidermal growth factor)-domain-containing protein 1) is a novel marker of ischemia, which is a cell surface-secreted protein in the platelets and endothelial cells. The aim of the study is to measure serum SCUBE-1 levels and investigate their association with uteroplacental blood flow in patients with preeclampsia. Methods: The study was conducted on patients with preeclampsia. Maternal serum SCUBE1 and IMA levels were the main outcomes. The control group consisted of gestational-age-matched pregnant women. Fetal umbilical artery (UA) pulsatility index (PI), middle cerebral artery PI, cerebroplacental ratio (CPR), and maternal uterine artery (UtA)-PI were also examined, and correlation analysis was performed to reveal the association between maternal serum SCUBE1 levels and Doppler findings. Results: The study group consisted of thirty-two preeclamptic patients, and the control group consisted of thirty-two uncomplicated singleton pregnancies. Maternal serum SCUBE1 and IMA levels were significantly higher in preeclamptic women compared to the control group (p < 0.000, p < 0.004, respectively). Mean UtA-PI values and fetal UA-PI values were significantly higher in preeclamptic pregnant women compared to the control group (p < 0.05, p < 0.05, respectively). However, the average CPR was significantly lower in pregnant women with preeclampsia (p < 0.05). While no significant correlation was found between maternal serum SCUBE1 levels and UA-PI and CPR (p > 0.05, p > 0.05, respectively), a significant correlation was found between right and left UtA-PI (p < 0.004, p < 0.006, respectively). Conclusions: The maternal serum SCUBE1 level is increased in patients with preeclampsia, and this increase is significantly correlated with the maternal uterine artery pulsatility index. Full article

The development of fetal organs can be impacted by systemic changes in maternal circulation, with the placenta playing a pivotal role in maintaining pregnancy homeostasis and nutrient exchange. In clinical obstetrics, oxytocin (OXT) is commonly used to induce labor. To explore the potential role of OXT in the placental homeostasis of OXT, we compared OXT levels in neonatal cord blood among neonates (23–42 weeks gestation) whose mothers either received prenatal OXT or experienced spontaneous labor. Our previous research revealed that the oxytocin receptor (OXTR), essential in forming the blood–retina barrier, is expressed in the retinal pigment epithelium (RPE). We hypothesized that perinatal OXT administration might influence the development of the neural retina and its vasculature, offering therapeutic potential for retinal diseases such as retinopathy of prematurity (ROP). Plasma OXT levels were measured using a commercial OXT ELISA kit. Human fetal RPE (hfRPE) cells treated with OXT (10 µM) were assessed for gene expression via RNA sequencing, revealing 14 downregulated and 32 upregulated genes. To validate these differentially expressed genes (DEGs), hfRPE cells were exposed to OXT (0.01, 0.1, 1, or 10 µM) for 12 h, followed by RNA analysis via real-time PCR. Functional, enrichment, and network analyses (Gene Ontology term, FunRich, Cytoscape) were performed to predict the affected pathways. This translational study suggests that OXT likely crosses the placenta, altering fetal OXT concentrations. RNA sequencing identified 46 DEGs involved in vital metabolic and signaling pathways and critical cellular components. Our results indicate that the perinatal administration of OXT may affect neural retina and retinal vessel development, making OXT a potential therapeutic option for developmental eye diseases, including ROP. Full article

Background/Objectives: Retinopathy of prematurity (ROP) is a retinal neovascular disease affecting preterm infants. Identifying risk factors for its development and progression is critical for effective screening and prevention. This study aimed to analyze the incidence of ROP and identify key risk factors for its development and progression. Methods: We conducted a prospective, observational cohort study on 455 neonates (gestational age [GA] < 32 weeks or birth weight < 1500 g) across eight Portuguese NICUs. Results: ROP incidence was 37.8%, with 4.6% requiring treatment. Multivariate analysis identified low GA and the number of red blood cell (RBC) transfusions as significant factors for ROP development and progression. After adjusting for these variables, platelet transfusions, high maximum fraction of inspired oxygen (FiO₂) in the second week, and surfactant use remained significantly associated with ROP development, while early and late sepsis, maternal chronic hypertension, and delayed enteral nutrition were associated with progression to ROP requiring treatment. Conclusions: These findings underscore the importance of addressing low GAs and adult RBC transfusions in ROP risk management and suggest that maximum FiO₂, platelet transfusions, and sepsis also play crucial roles. Larger studies are needed to validate these results and explore preventive interventions, particularly regarding the impact of multiple adult RBC transfusions on fetal hemoglobin percentages. Full article