Atypical pulmonary metastases in children: the spectrum of radiologic findings.

Pulmonary nodules present a diagnostic challenge when they appear as atypical metastases in pediatric oncology patients. Chest computed tomography (CT) is the primary imaging modality for assessing lung nodules. In pediatric populations, Wilms tumor and osteosarcoma are the cancers most likely to produce pulmonary metastasis, both typical and atypical. This pictorial essay provides a thorough description of the specific radiologic features of atypical pediatric pulmonary metastases, and their pathogenesis and differential diagnosis. We also address diagnostic approaches to incidental lung nodules in healthy children found in the literature. Our aim is to help radiologists identify atypical lung metastases on CT, ensuring that children receive prompt, and potentially lifesaving, treatment.

Novel NCF2 Mutation Causing Chronic Granulomatous Disease.

Chronic granulomatous disease (CGD) is a rare primary immunodeficiency disorder caused by defects in the NADPH oxidase complex. Mutations in NCF2 encoding the cytosolic factor p67phox result in autosomal recessive CGD. We describe three patients with a novel c.855G>C NCF2 mutation presenting with diverse clinical phenotype. Two siblings were heterozygous for the novel mutation and for a previously described exon 8-9 duplication, while a third unrelated patient was homozygous for the novel mutation. Mutation pathogenicity was confirmed by abnormal DHR123 assay and absent p67phox production and by sequencing of cDNA which showed abnormal RNA splicing. Clinically, the homozygous patient presented with suspected early onset interstitial lung disease and NCF2 mutation was found on genetic testing performed in search for surfactant-related defects. The two siblings also had variable presentation with one having history of severe pneumonia, lymphadenitis, and recurrent skin abscesses and the other presenting in his 30s with discoid lupus erythematosus and without significant infectious history. We therefore identified a novel pathogenic NCF2 mutation causing diverse and unusual clinical phenotype.

The Effect of a 30-Min Water-Pipe Smoking Session on Cognitive Measures and Cardio-Pulmonary Parameters.

INTRODUCTION: One session of water-pipe tobacco smoking (WPS) can increase carboxyhemoglobin (COHb) to levels comparable to those reported in carbon monoxide poisoning, which may cause memory impairment and confusion. METHODS: A prospective study evaluating healthy volunteers pre- and post-30 min of WPS session. Primary outcome parameters were executive cognitive measures [digit span test and Paced Auditory Serial Addition Test (PASAT)]. The effect of repeated cognitive testing 30 min apart without WPS was evaluated in age- and sex-matched healthy volunteers. Secondary outcome parameters included cardio-pulmonary, COHb, serum nicotine, and cytokine changes. RESULTS: Thirty-five subjects aged 25.6 ± 4.5 years smoked water-pipe for a 30-min session. Control group included 20 subjects aged 25.2 ± 5.1 years. Digit span test median score decreased after WPS (16 and 15, respectively, p = .003), insignificant decrease in controls. Median PASAT score increased after WPS (49 and 52, respectively, p = .009); however, a much larger significant increase was observed in controls (p ≤ .001). One WPS session resulted in significant increases in heart and respiratory rates and significant decrease in FEF25-75%. Post WPS, median COHb levels increased (from 2.2% to 10.7%, p < .0001) as did median serum nicotine levels (from 1.2 to 26.8 ng/mL, p < .0001). Serum cytokines levels: IL-2 and IL-6 increased (p < .0001 for each), and IL-10 and IL-5 decreased (p < .0001 and p = .04, respectively). CONCLUSIONS: One session of WPS resulted in significant negative effects on cognitive executive measures, significant increases in COHb and serum nicotine levels, and significant changes in serum cytokines. Our findings call for increasing awareness towards the possible consequences of cognitive alterations following a 30-min session of WPS. IMPLICATIONS: One 30-min session of water-pipe smoking resulted in negative effects on executive cognitive measures, increased carboxyhemoglobin and serum nicotine, and significant changes in serum cytokine levels. This study adds to the accumulating evidence on the harmful effects of water-pipe smoking, a growing epidemic, and calls for awareness of its possible consequences of acute cognitive alterations.

Incidence of congenital thoracic malformations detected by prenatal ultrasound.

BACKGROUND: The increased and earlier use of prenatal ultrasound has facilitated the detection of congenital thoracic malformations (CTMs). Our Pediatric Pulmonology Institute follows an increasing number of patients with CTMs. Thus, we aimed to evaluate and describe prenatal sonographic findings of CTM, and to estimate changes in detection rates of CTMs over a period of 16 years. METHODS: A retrospective, cross-section analysis of prenatal ultrasound (US) screening tests carried out in a large community-based clinic, comparing two periods: 2001-2007 and 2007-2017. RESULTS: A total of 34 716 prenatal US were performed at a median gestational age of 15.4 weeks (range, 11.6-23.9) and 15.7 weeks (range, 12-33.6) in 2001-2007 and 2007-2017, respectively. In 2001-2007, 12 016 prenatal US tests detected 19 CTMs, compared to 30 CTMs in 22 700 tests in 2007-2017. Detection rates did not change (1.58/1,000 in 2001-2007 versus 1.32/1,000 in 2007-2017, P = 0.64). The most common abnormality was congenital pleural effusion (CPE) (17 cases, 34.7%), followed by congenital pulmonary airway malformation) and congenital diaphragmatic hernia; 13 cases each, 26.5%. Twenty CTMs, mainly congenital diaphragmatic hernia and CPE, were associated with other fetal lesions. CONCLUSIONS: Congenital diaphragmatic hernia and CPE tend to appear with multiple lesions and warrant further attention. The incidence rates stayed stable when comparing the last decade to previous years. Thus, the increased referral of CTM can be attributed to an increase in the number of prenatal screening studies performed, rather than a true higher incidence.

Bronchoscopy and Bronchoalveolar Lavage in the Diagnosis and Management of Pulmonary Infections in Immunocompromised Children.

BACKGROUND: Immunocompromised children are at high risk of rapid deterioration and of developing life-threatening pulmonary infections. Etiologies in this setting are diverse, including those that are infectious and noninfectious, and many etiologies may coexist. Accurate diagnosis is required for the rational use of medications. Fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL) can identify infectious causes in this population. OBJECTIVES: The aims of this study were to evaluate diagnostic rate, safety, and changes in treatment following FOB with BAL, when applied with advanced laboratory diagnostic techniques. PATIENTS AND METHODS: We reviewed the records of children who underwent FOB with BAL during the period spanning from 2006 to 2014 in the Hematology-Oncology Department. BAL samples were processed in microbiology, virology, cytology, and molecular laboratories. RESULTS: Antimicrobials were initiated in 91 of 117 children. BAL yielded an infectious etiology in 55 episodes. Management was altered in 74 patients following a positive (40/55) or a negative (30/54) result (4 patients had missing data). No severe complications associated with the procedures occurred. CONCLUSIONS: Most immunocompromised patients with pulmonary manifestations are treated empirically with multiple medications. Evaluation FOB/BAL is a useful diagnostic tool, and seems to have changed the course of therapy in more than half of patients, by initiation or cessation of treatment. FOB/BAL is a safe diagnostic tool for the evaluation of pulmonary manifestations in this setting.

Intermittent inhaled tobramycin and systemic cytokines response in CF patients with Pseudomonas aeruginosa.

INTRODUCTION: CF pulmonary guidelines recommend alternate therapy (one month on, one month off) with inhaled tobramycin for chronic Pseudomonas aeruginosa colonization in cystic fibrosis (CF). Tobramycin-inhaled powder (TIP™) is increasingly replacing time-consuming nebulizer therapy. It is unclear whether laboratory parameters change during the month off period compared with the month on therapy. PURPOSE: Our aim was to assess whether spirometry, lung clearance index and circulating inflammatory markers differ between on/off treatment periods. MATERIALS AND METHODS: A prospective pilot study evaluating CF patients treated with TIP, on two consecutive months (on/off) therapy. The evaluations were performed at the end of a month off therapy (1-2 days before the initiation of TIP) and after 28 days of treatment with TIP (1-2 days after the end of the treatment cycle). RESULTS: Nineteen CF patients (10 males) with a mean age of 18.7±9.7 years and BMI (body mass index) of 19.62±3.53 kg/m2 were evaluated. After a month off treatment with TIP, spirometry parameters and lung clearance index remained unchanged. IL-6 increased significantly (p=0.022) off treatment. There was a non-significant change in the other inflammatory cytokines off therapy [hs-CRP, IL-8,TNF-α, α1-antitrypsin (α1AT) and neutrophilic elastase]. CONCLUSIONS: The results of lung function parameters support the relative stability of CF patients during the month off therapy; however, the difference in serum IL-6 raises the possibility of ongoing higher degrees of inflammation during the month off therapy with TIP. The small sample size and the multiple parameters evaluated preclude firm conclusions; therefore, larger multicenter studies are needed to assess the on/off treatment strategy.

Factors Associated with Recurrence of Tracheoesophageal Fistula.

BACKGROUND: Recurrence of tracheoesophageal fistula (TEF) is reported in 8-20% patients. Factors that may influence recurrence of fistula beyond the postoperative period are not clear. OBJECTIVES: To evaluate possible factors associated with recurrence of TEF beyond the immediate postoperative period. METHODS: A single center, retrospective comparison of patients with and without recurrence of TEF was conducted. Medical records of patients previously operated for TEF who were followed in our pediatric pulmonary institute between January 2007 and December 2016 were reviewed. RESULTS: The medical records of 74/77 patients previously operated for TEF were evaluated. Nine patients (12%) had a recurrence of TEF and 65 did not. These groups had similar age and gender distribution and similar prevalence of VACTERL association. In addition, they had similar length of atretic gap, rates of thoracoscopic surgery, rates of prolonged need for respiratory assistance post-surgery, and frequency of gastrointestinal symptoms. Notably, the patients who had recurrent TEF had significantly more hospitalizations for respiratory symptoms (P = 0.011) and significantly more episodes of clinical bronchiolitis per patient (P < 0.0001). In addition, the patients with recurrent TEF had significantly more episodes of positive polymerase chain reaction for viruses (P = 0.009). CONCLUSIONS: Hospitalizations for respiratory symptoms as well as clinical and/or viral bronchiolitis are associated with recurrence of TEF. Even though cause and effect cannot be established, these patients should undergo meticulous evaluation for the possibility of recurrence of TEF.

Cleaning and infection control of airway clearance devices used by CF patients.

Respiratory treatment for cystic fibrosis (CF) patients includes use of respiratory devices. Contamination of airway clearance devices has not been adequately explored. We aimed to determine whether airway clearance devices are contaminated after use and whether cleaning guidelines for nebulizers are as effective for airway clearance devices. Patients brought their airway clearance devices to the clinic. Swabs from the devices were taken before and after cleaning and were cultured for bacterial counts. Total colony-forming units (CFU) was determined, and predominant colonies were identified using Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry technology. Thirty devices were collected from 23 patients. Most of the devices (28/30) were contaminated when brought to the clinic. Complete bacterial eradication was achieved in 15 (50%) samples and partial eradication in 9 (30%). The cleaning was totally ineffective in four samples. Median CFU decreased significantly from 1250 (IQR 25-75% 175-10.000) to 0 (IQR 25-75% 0-700) before and after cleaning ( p < 0.0001). The predominant organisms were identified in five samples only, and there was no concordance with sputum culture results. Airway clearance devices are contaminated after use, and appropriate cleaning can reduce contamination. The effect on disease progression in CF patients is unclear. There is a need for infection prevention and control guidelines for the growing number of respiratory devices.

Systematic Analysis of CCNO Variants in a Defined Population: Implications for Clinical Phenotype and Differential Diagnosis.

Reduced generation of multiple motile cilia (RGMC) is a novel chronic destructive airway disease within the group of mucociliary clearance disorders with only few cases reported. Mutations in two genes, CCNO and MCIDAS, have been identified as a cause of this disease, both leading to a greatly reduced number of cilia and causing impaired mucociliary clearance. This study was designed to identify the prevalence of CCNO mutations in Israel and further delineate the clinical characteristics of RGMC. We analyzed 170 families with mucociliary clearance disorders originating from Israel for mutations in CCNO and identified two novel mutations (c.165delC, p.Gly56Alafs*38; c.638T>C, p.Leu213Pro) and two known mutations in 15 individuals from 10 families (6% prevalence). Pathogenicity of the missense mutation (c.638T>C, p.Leu213Pro) was demonstrated by functional analyses in Xenopus. Combining these 15 patients with the previously reported CCNO case reports revealed rapid deterioration in lung function, an increased prevalence of hydrocephalus (10%) as well as increased female infertility (22%). Consistent with these findings, we demonstrate that CCNO expression is present in murine ependyma and fallopian tubes. CCNO is mutated more frequently than expected from the rare previous clinical case reports, leads to severe clinical manifestations, and should therefore be considered an important differential diagnosis of mucociliary clearance disorders.

DNAH11 Localization in the Proximal Region of Respiratory Cilia Defines Distinct Outer Dynein Arm Complexes.

Primary ciliary dyskinesia (PCD) is a recessively inherited disease that leads to chronic respiratory disorders owing to impaired mucociliary clearance. Conventional transmission electron microscopy (TEM) is a diagnostic standard to identify ultrastructural defects in respiratory cilia but is not useful in approximately 30% of PCD cases, which have normal ciliary ultrastructure. DNAH11 mutations are a common cause of PCD with normal ciliary ultrastructure and hyperkinetic ciliary beating, but its pathophysiology remains poorly understood. We therefore characterized DNAH11 in human respiratory cilia by immunofluorescence microscopy (IFM) in the context of PCD. We used whole-exome and targeted next-generation sequence analysis as well as Sanger sequencing to identify and confirm eight novel loss-of-function DNAH11 mutations. We designed and validated a monoclonal antibody specific to DNAH11 and performed high-resolution IFM of both control and PCD-affected human respiratory cells, as well as samples from green fluorescent protein (GFP)-left-right dynein mice, to determine the ciliary localization of DNAH11. IFM analysis demonstrated native DNAH11 localization in only the proximal region of wild-type human respiratory cilia and loss of DNAH11 in individuals with PCD with certain loss-of-function DNAH11 mutations. GFP-left-right dynein mice confirmed proximal DNAH11 localization in tracheal cilia. DNAH11 retained proximal localization in respiratory cilia of individuals with PCD with distinct ultrastructural defects, such as the absence of outer dynein arms (ODAs). TEM tomography detected a partial reduction of ODAs in DNAH11-deficient cilia. DNAH11 mutations result in a subtle ODA defect in only the proximal region of respiratory cilia, which is detectable by IFM and TEM tomography.

Lung Clearance Index (LCI) in Patients with Bronchiolitis Obliterans: A Preliminary Report and Comparison to Cystic Fibrosis Patients.

INTRODUCTION: Bronchiolitis obliterans (BO) is a chronic airway disease following an insult to the lower respiratory tract. Lung clearance index (LCI) measures ventilation inhomogeneity and has been studied in cystic fibrosis (CF). We aimed to evaluate LCI in BO and to compare it to LCI in CF patients. METHODS: LCI was measured in BO patients, compared to CF patients, and correlated with spirometry and CT findings. RESULTS: Twenty BO patients and 26 CF patients (with similar mean age and BMI) underwent evaluation. FEV1 % and FEF25-75 % predicted were significantly lower in the BO group (60.5 ± 17.8 vs. 72.7 ± 20.7, p = 0.041, and 42.8 ± 22.8 vs. 66.4 ± 37.4, p = 0.017, respectively). In both groups, LCI was inversely correlated with FVC %, FEV1 %, and FEF25-75 % predicted. LCI  % was slightly higher (190.4 ± 63.5 vs. 164.9 ± 39.4, p = 0.1) and FRC gas % (measured by multiple breath washout) was significantly higher in the BO group (92.5 ± 35.9 vs. 71.3 ± 18, p = 0.014). The strength of statistical association between the lower FEF25-75 % values and the higher LCI values was stronger in BO patients. CONCLUSIONS: Similar to CF, LCI may provide estimation of ventilation inhomogeneity in BO. The results indicate greater small airway involvement and air trapping in BO. Further prospective longitudinal studies evaluating the correlation of LCI measurements with multiple clinical and physiological parameters should be performed to assess the clinical benefit of LCI measurement in BO.

Maximal flow at functional residual capacity in asthmatic preschool children.

BACKGROUND: Many preschool children will perform correct peak-flow but will not exhale to residual volume, thus limiting the determination of airways obstruction. The maximal flow measured at function residual capacity (V'maxFRC) is independent of lung empting and could potentially serve as a parameter for describing flow at low lung volumes. The study determines the detection of airway obstruction/dilation in asthmatic preschool children by V'maxFRC, compared to FEV1 and FEF25-75. METHODS: Children performed bronchial provocation test (BPT; n = 26) or received bronchodilators (Post-BD; n = 31). V'maxFRC was extracted at inspiratory capacity point of flow/volume maneuvers. The %change of V'maxFRC from baseline was compared with changes in various spirometry indices and to values obtained from our previously studied healthy control children. RESULTS: FEV1, FEF25-75, and V'maxFRC decreased by 30.9 ± 12.2%, 46.2 ± 10.9%, and 36.6 ± 8.0%, respectively, while FRC increased by 37.0 ± 24.9% at end of the BPT. Post-BD spirometry values increased by 17.1 ± 16.1%, 47.0 ± 42.2, and 45 ± 24%, respectively (p < 0.0001). A positive response to bronchodilators was observed in 15/31 (48%) children by FEV1, in 22/31 (71%) children by V'maxFRC, and in 21/31 children by FEF25-75. CONCLUSION: V'maxFRC detects airway obstruction/dilation in young asthmatic children similar to FEF25-75 and FEV1. V'maxFRC may be a valuable index in preschool children who cease exhalation prematurely. Digitally measured V'maxFRC should confirm the actual values in a wider age range in healthy and disease states.

Evaluation of high-sensitivity serum CRP levels compared to markers of airway inflammation and allergy as predictors of methacholine bronchial hyper-responsiveness in children.

BACKGROUND: Bronchial hyper-responsiveness assessed by the methacholine challenge test (MCT) may aid in the diagnosis of asthma, while a negative MCT can help in excluding the diagnosis. Laboratory measures that predict the results of MCT are expected to reduce the number of procedures. We evaluated the capacity of serum high-sensitivity C-reactive protein (hs-CRP) to predict positive or negative MCT in school-aged children and compared it to a marker of airway inflammation, fractional exhaled nitric oxide (FeNO), and markers of allergic sensitization, immune globulin E (IgE) and peripheral blood eosinophils. PATIENTS AND METHODS: Children aged 6-18 years referred for MCT were included in the study. The results of the MCT were compared to hs-CRP levels and FeNO levels, IgE, and peripheral blood eosinophil counts. RESULTS: Of the 131 children assessed, 63 (48 %) patients had positive MCTs (Group I), and 68 (52 %) had negative MCTs (Group II). The best cut-off values to predict a positive MCT by receiver-operating characteristic curves were: 23 ppb for FeNO, 120 IU/mL for IgE, and 500/mL for eosinophils; no cut-off value was found for hs-CRP. The odds ratio for a positive MCT with the above cut-off points were 2.43 (1.05-5.61) for FeNO, 2.4 (1.01-5.74) for IgE, 3.32 (1.13-9.75) for eosinophils, and NS for hs-CRP. No correlation was found between hs-CRP and FeNO, IgE, or eosinophil levels. CONCLUSIONS: hs-CRP levels were not helpful, while FeNO, IgE, and eosinophils were useful in the prediction of methacholine bronchial hyper-responsiveness in our group of children.

Clinical Significance of Mucor in Airway Culture of Immunocompetent Patients With Chronic Lung Disease.

OBJECTIVES: Mucor within the airways of immunocompromised patients often signifies an invasive life-threatening infection. However, its significance in immunocompetent patients with chronic lung diseases is less clear. We aimed to assess the clinical implication of mucor in airway-secretion cultures of these patients. METHODS: A single-center retrospective cohort study was performed. Patients with cystic fibrosis (CF), primary ciliary dyskinesia (PCD) or non-CF/non-PCD bronchiectasis followed in our Pediatric Pulmonary Institute, with sputum or bronchoalveolar lavage cultures growing Mucorales molds in the years 2010-2022, were included. Demographic and clinical parameters such as body mass index and spirometry values (forced expiratory volume at 1 second) were collected and compared with values up to 12 months prior to and following the index (positive culture) visit. RESULTS: A total of 27 patients of whom 22 (82%) patients were with CF, 3 with PCD (11%) and 2 (7%) with non-CF/non-PCD bronchiectasis were included. Median age was 21.8 (14.9-32.1) years, with forced expiratory volume at 1 second of 62.8% ± 21.9% at the index visit. None of the patients developed disseminated disease, none had clinical or radiological evidence of fungal disease and none required antifungal therapy. Throughout the 12 months prior to and following the positive cultures, no significant changes were noted in body mass index, forced expiratory volume at 1 second, frequency of pulmonary exacerbations, days of hospitalization or days of antibiotic treatment. CONCLUSIONS: Evidence of mucor in airway cultures of immunocompetent patients with chronic lung disease does not necessarily signify clinical deterioration nor suggests invasive fungal disease. Larger, long-term prospective studies are required to obviate the need for a thorough evaluation in these patients.

Assessment of Relative Energy Deficiency in Sport (REDs) Risk among Adolescent Acrobatic Gymnasts.

Energy imbalance exposes athletes to relative energy deficiency in sports (REDs) syndrome. Data on energy consumption, REDs, and bone mineral density (BMD) in adolescent acrobatic gymnasts, especially in males, are scarce. Our aim was to examine the eating habits, energy balance, body composition, and BMD of these athletes. In this study, 18 healthy adolescents participating in competitive acrobatic gymnastics completed a questionnaire, underwent a dual-energy X-ray absorptiometry scan (DXA), received a food log, and had their activities monitored for 3 days. Eighteen acrobats were enrolled (mean age: 14.3 ± 1.2 years; males: 6/18). The mean total body BMD Z-score was 0.4 ± 1.0. Top-position acrobats (7/18) had significantly lower total body BMD Z-scores than base-positioned acrobats (-0.2 ± 0.3 vs. 0.8 ± 0.3, p = 0.032), though their forearms were not significantly different (0.2 ± 0.5 vs. 0.8 ± 0.7, p = 0.331). No sex differences were found for BMD Z-scores, BMI, or energy availability. The BMD parameters of the acrobats were within the normal range for a healthy pediatric population, although three had low BMDs (<-1 SD) for healthy athletes. Total body and LS BMD Z-scores were significantly lower in top-position athletes compared to base-position athletes. These findings suggest personalized (top vs. base) training programs (high-impact training) that may achieve better health outcomes.

Pulmonary functions, nasal symptoms, and quality of life in patients with primary ciliary dyskinesia (PCD).

BACKGROUND: Several factors may influence quality of life (QOL) for patients with primary ciliary dyskinesia (PCD). We aimed to evaluate the association between pulmonary functions, nasal symptoms and QOL in PCD patients. METHODS: A prospective single center study. Patients performed spirometry, whole body plethysmography, forced oscillation technique (FOT), lung clearance index (LCI), 6-min walk test (6MWT), and filled two questionnaires: a specific PCD QOL questionnaire (PCD-QOL) and Sino-nasal outcome test (SNOT-22) questionnaire, assessing symptoms of chronic rhinosinusitis and health related QOL. RESULTS: Twenty-seven patients (56% females), age 19.4 ± 10.5 years were included; their, FEV1 was 74.6 ± 22.7%, and RV/TLC was (157.3 ± 39.3% predicted). Health perception and lower respiratory symptoms domains of PCD-QOL had the lowest score (median [IQR]: 50 [33.3-64.6] and 57.1 [38.9-72.2], respectively). FOT parameters correlated with several PCD-QOL domains. R5 z-score (indicating total airway resistance) and AX z-score (indicating airway reactance) correlated negatively with physical domain (r = -0.598, p = .001, and r = -0.42, p = .03, respectively); R5 z-score also correlated negatively with hearing domain (r = -0.57, p = .002). R5-20 z-score (indicating small airway resistance) correlated negatively with role domain (r = -0.49, p = .03). SNOT-22 score correlated negatively with several PCD-QOL domains (lower respiratory symptoms r = -0.77, p < .001; physical r = -0.72, p < .001; upper respiratory symptoms r = -0.66, p < .001). No correlations were found between spirometry values, LCI, 6MWT, and PCD-QOL. CONCLUSIONS: FOT suggested small airway dysfunction, and correlated negatively with several PCD-QOL domains. Nasal symptoms had strong negative correlations with PCD-QOL. Larger longitudinal studies will further elucidate factors affecting QOL in PCD.

Maternal and fetal outcomes in multiparous women with Cystic Fibrosis.

BACKGROUND: Quality of life and survival in Cystic Fibrosis (CF) have improved dramatically, making family planning a feasible option. Maternal and perinatal outcomes in women with CF (wwCF) are similar to those seen in the general population. However, the effect of undergoing multiple pregnancies is unknown. METHODS: A multinational-multicenter retrospective cohort study. Data was obtained from 18 centers worldwide, anonymously, on wwCF 18-45 years old, including disease severity and outcome, as well as obstetric and newborn complications. Data were analyzed, within each individual patient to compare the outcomes of an initial pregnancy (1st or 2nd) with a multigravid pregnancy (≥3) as well as secondary analysis of grouped data to identify risk factors for disease progression or adverse neonatal outcomes. Three time periods were assessed - before, during, and after pregnancy. RESULTS: The study population included 141 wwCF of whom 41 (29%) had ≥3 pregnancies, "multiparous". Data were collected on 246 pregnancies, between 1973 and 2020, 69 (28%) were multiparous. A greater decline in ppFEV1 was seen in multiparous women, primarily in pancreatic insufficient (PI) wwCF and those with two severe (class I-III) mutations. Multigravid pregnancies were shorter, especially in wwCF over 30 years old, who had high rates of prematurity and newborn complications. There was no effect on pulmonary exacerbations or disease-related complications. CONCLUSIONS: Multiple pregnancies in wwCF are associated with accelerated respiratory deterioration and higher rates of preterm births. Therefore, strict follow-up by a multidisciplinary CF and obstetric team is needed in women who desire to carry multiple pregnancies.