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.

Foreign body aspiration in Israeli children during the COVID-19 pandemic.

BACKGROUND: Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, there has been a decline in pediatric emergency department visits. Our aim was to assess the pattern of pediatric foreign body aspiration (FBA) during the first year of the COVID-19 pandemic, in comparison to the prior years. METHODS: In this retrospective multicenter study, we compared the number of children who presented with FBA during the COVID-19 year (March 1, 2020 to February 28, 2021) to the annual average of the years 2016-2019. We also compared the lockdown periods to the postlockdown periods, and the percentage of missed FBA, proven FBA, and flexible bronchoscopy as the removal procedure. RESULTS: A total of 345 children with FBA from six centers were included, 276 in the pre-COVID-19 years (average 69 per year) and 69 in the COVID-19 year. There was no difference in the prevalence of FBA between the COVID-19 year and any of the prior 4 years. Examining the lockdown effect, the monthly incidence of FBA dropped from a pre-COVID-19 average of 5.75 cases to 5.1 cases during lockdown periods and increased to 6.3 cases in postlockdown periods. No difference in the percentage of missed FB or proven FB was observed. There was a significant rise in the usage of flexible bronchoscopy as the removal procedure (average of 15.4% vs. 30.4%, p = 0.001). CONCLUSION: There were fewer cases of pediatric FBA during lockdown periods, compared to post-lockdown periods, presumably related to better parental supervision, with no difference in the prevalence of FBA during the COVID-19 year.

Being overweight and born in the spring are associated with an increased risk for rhinitis.

AIM: To explore the relationship between the season of birth and the prevalence of recurrent or chronic rhinitis (rhinitis). METHODS: The medical records of consecutive 17-year-old conscripts to the Israeli army were reviewed. We compared the prevalence of rhinitis between children born during different seasons. Multivariate analysis was performed with additional variables. RESULTS: The prevalence of rhinitis among the 1.1 million recruits was 7.1% in males and 5.3% in females. The association between birth season and the prevalence of rhinitis was highly significant (p < 0.001 for both genders). Spring was the birth season with the highest prevalence of rhinitis (7.4% in males and 5.5% in females). Males born in the winter and females born in the autumn had the lowest prevalence of rhinitis (6.7%, and 5.2% respectively). There was an increased odds ratio for rhinitis among those with a body mass index above 25, higher cognitive score and maternal birth country out of Israel or Africa. CONCLUSIONS: There was an increased risk of rhinitis among young Israeli adults who were born in the spring, were overweight and had a higher cognitive-score. Family planning to avoid a spring birth and preventing overweight may reduce the risk of chronic rhinitis.

Combining cytogenetic and genomic technologies for deciphering challenging complex chromosomal rearrangements.

Complex chromosomal rearrangements (CCRs), a class of structural variants (SVs) involving more than two chromosome breaks, were classically thought to be extremely rare. As advanced technologies become more available, it has become apparent that CCRs are more common than formerly thought, and are a substantial cause of genetic disorders. We attempted a novel approach for solving the mechanism of challenging CCRs, which involve repetitive sequences, by precisely identifying sequence-level changes and their order. Chromosomal microarray (CMA) and FISH analyses were used for interpretation of SVs detected by whole exome sequencing (WES). Breakpoint junctions were analyzed by Nanopore sequencing, a novel long-read whole genome sequencing tool. A large deletion identified by WES, encompassing the FOXF1 enhancer, was the cause of alveolar capillary dysplasia and respiratory insufficiency, resulting in perinatal death. CMA analysis of the newborn's mother revealed two duplications encompassing the deleted region in the proband, raising our hypothesis that the deletion resulted from the mother's CCR. Breakpoint junctions of complex SVs were determined at the nucleotide level using Nanopore long-read sequencing. According to sequencing results of breakpoint junctions, the CCR in the newborn was considered the consequence of at least one double-strand break during meiosis, and reassembly of DNA fragments by intra-chromosomal homologous recombination. Our comprehensive approach, combining cytogenetics and long-read sequencing, enabled delineation of the exact breakpoints in a challenging CCR, and proposal of a mechanism in which it arises. We suggest applying our integrative approach combining technologies for deciphering future challenging CCRs, enabling risk assessment in families.

Factors associated with resolution of childhood asthma by the age of 17: Large cohort analysis.

BACKGROUND: Many children with asthma will become asymptomatic during adolescence. In this study, we evaluated factors associated with recovery from asthma by the age of 17. METHODS: The medical records of 17-year-old conscripts to the Israeli army with asthma were compared with the records of conscripts with rigorously diagnosed resolved asthma. We assessed the association between the following parameters and asthma resolution: body mass index (BMI), recurrent rhinitis, birth season, socioeconomic level, and cognition. RESULTS: Sixty-eight thousand and ninety conscripts with active asthma were compared to 14,695 with resolved asthma. In univariate analysis, rhinitis, overweight, underweight, higher socioeconomic level, and lower cognitive score were associated with active asthma (p < 0.001 for both sexes), but not the season of birth. In multivariate analysis, only overweight, underweight, rhinitis, and lower cognitive score (p < 0.001 for both sexes) remained significantly associated with persistence of asthma. CONCLUSIONS: Although association does not prove causation, our finding is another reason to encourage adolescents with asthma to maintain a normal body weight. Prospective interventional studies are needed in order to decide whether changing weight to ensure BMI is within the ideal range and controlling rhinitis increases the odds of resolution of asthma in adolescence.

The impact of pneumococcal conjugate vaccine on the prevalence and severity of hospitalizations for pneumonia in children.

Pneumococcal conjugate vaccines (PCV) were introduced into the Israeli national immunization plan starting with the heptavalent PCV7 in 2009 and then PCV13 in the late 2010. The objective of this study was to determine the vaccines' impact on hospitalization rates for community-acquired pneumonia on the severity of the pneumonia episodes and upon pneumococcal serotype distribution. We retrospectively reviewed all children hospitalized in our institution with pneumonia, aged between 1 and 16 years, between the years 2006 and 2015. Demographic, clinical, and laboratory data between three time periods: pre-PCV, PCV7, and PCV13, were compared. During the study period, 1375 children were hospitalized with pneumonia. A gradual decline in hospitalization rates due to pneumonia was observed starting in 2006 in the pre-PCV period and continued until after the introduction of PCV13. A similar trend was observed in pneumonias with a culture positive for S. pneumoniae. Pleural effusion was observed in 24% of all pneumonias, and this percentage was stable throughout the study period. The average age at hospitalization increased during the study period, as did the average duration of hospital stay. Pneumococcal serotypes included in the vaccine were isolated less frequently during the study and non-vaccine serotypes tended to appear more frequently. Pediatric pneumonia hospitalization rates continued to decline since the introduction of PCV without increasing the frequency of complications. Pneumococcal serotype distribution shifted in parallel. Our findings confirm the efficacy of PCV and support the evidence to include more serotypes in the next generation of PCV.

The Use of Infant Pulmonary Function Tests in the Diagnosis of Neuroendocrine Cell Hyperplasia of Infancy.

BACKGROUND: Infant pulmonary function tests (iPFTs) in subjects with neuroendocrine cell hyperplasia of infancy (NEHI) have demonstrated substantial expiratory airflow obstruction and air trapping. RESEARCH QUESTION: Can indices from iPFTs be used in the diagnosis of NEHI? STUDY DESIGN AND METHODS: This is an observational case-control study evaluating iPFT results from a registry of patients assessed at the Hadassah Hebrew University Medical Center between 2008 and 2018. iPFTs results in infants with NEHI were compared to two disease control infant groups (infants evaluated for recurrent wheezing and infants evaluated due to prematurity) and a spirometry control group of infants with normal expiratory airflow, using the Kruskal-Wallis test. Receiver operating characteristic (ROC) curves were used to assess the diagnostic accuracy of iPFT indices. RESULTS: We evaluated iPFT data in 481 infants (15, NEHI; 292, wheezing; 128, premature; and 46, spirometry control group). Infants with NEHI had significantly increased trapped air volumes (median functional residual capacity measured with infant whole-body plethysmography [FRCpleth] was 199% predicted; median ratio of residual volume to total lung capacity was 59% predicted) when compared with results in all evaluated groups of infants (P < .001), including multiple pairwise comparisons. Airflow limitation was demonstrated in infants with NEHI when compared with the infants in the spirometry control group but was similar to the two disease control groups. FRCpleth had the best discriminatory ability for NEHI diagnosis, with an FRCpleth ≥ 150% predicted demonstrating a ROC of 0.91 (95% CI, 0.82-1.00), sensitivity of 86.7% (95% CI, 59.5%-98.3%), and specificity of 95.5% (95% CI, 93.2%-97.3%). INTERPRETATION: Findings on iPFTs of markedly increased air trapping, out of proportion to the degree of airflow limitation, are characteristic of infants with NEHI. iPFT results demonstrating an FRCpleth ≥ 150% predicted are highly specific for NEHI and may aid in early diagnosis. Further research is required to confirm these findings in a prospective cohort and to understand the pathophysiologic explanation for these findings.

Are there gender differences in blood oxygen saturation in prepubertal children?

INTRODUCTION: Previous studies reported higher oxygen saturation (SpO2 ) in healthy young adult females as compared to males. The objective of the current study was to evaluate whether or not similar differences exist in prepubertal children. METHODS: SpO2 levels, respiratory rate, and pulse were measured in 4- to 10-year-old males and females. Anthropometric variables, including ethnic origin, age, height, weight, BMI (Body Mass Index), BSA (Body Surface Area), barometric pressure, and altitude above sea level were collected as well. RESULTS: Ninety five males and 93 females participated in the study. Groups were similar, in terms of respiratory rate, pulse, and anthropometric variables. Mean SpO2 in males was 96.95 ± 1.09%, similar to SpO2 in females measuring 96.85 ± 0.98%, P = .52. CONCLUSION: In contrast to young adults, there is no gender-related difference in mean oxygen saturation in prepubertal healthy children. It is likely that this difference is due to variations in age-related sex hormones. Further studies are needed to explore the mechanism explaining why prepubertal children do not show gender-specific differences in oxygen saturation in contrast to adults.

Baseline Cystic fibrosis disease severity has an adverse impact on pregnancy and infant outcomes, but does not impact disease progression.

BACKGROUND: With increasing longevity and quality of life in adults with Cystic fibrosis (CF), growing maternity rates are reported. Women with severe CF are becoming pregnant, with unpredictable maternal and fetal outcomes. AIM: To determine how baseline disease severity, pancreatic insufficiency (PI) and Pseudomonas aeruginosa (PA) infection affect fertility, the pregnancy course, delivery, neonatal outcome, and subsequent disease progression. METHODS: A multicenter-retrospective cohort study. Data on patients that had been pregnant between 1986-2018 was collected from ten CF centers worldwide. Disease severity [mild or moderate-severe (mod-sev)] was defined according to forced expiratory volume % predicted in 1 second (FEV1) and body mass index (BMI). Three time periods were compared, 12 months prior to conception, the pregnancy itself and the 12 months thereafter. RESULTS: Data was available on 171 pregnancies in 128 patients aged 18-45 years; 55.1% with mod-sev disease, 43.1% with PI and 40.3% with PA. Women with mod-sev disease had more CF-related complications during and after pregnancy and delivered more preterm newborns. However, FEV1 and BMI decline were no different between the mild and mod-sev groups. A more rapid decline in FEV1 was observed during pregnancy in PI and PA infected patients, though stabilizing thereafter. PI was associated with increased risk for small for gestational age infants. CONCLUSION: Baseline disease severity, PA infection and PI have an adverse impact on infant outcomes, but do not impact significantly on disease progression during and after pregnancy. Consequently, pregnancies in severe CF patients can have a good prognosis.

The prognostic value of C-reactive protein for children with pneumonia.

AIM: To measure the prognostic value of C-reactive protein (CRP) and its ability to predict pneumonia-associated complications. METHODS: A 3.75-years retrospective cohort analysis of all paediatric emergency department visits with a discharge diagnosis of pneumonia. Visits where CRP was not measured or with a discharge diagnosis of viral pneumonia were excluded. The following five outcomes were studied: hospitalisation, presence of parapneumonic effusion (PPE), placement of a chest drain, admission to paediatric intensive care unit (PICU) and bacteremia. A multivariate model was constructed and validated using k-fold cross-validation. RESULTS: During the study time period, there were 2561 visits for pneumonia, of which 810 were included in our analysis. The median age of included children was 3.2 years (range 0.2-17.7). Overall, 38.8% visits ended in hospitalisation, 2.2% required admission to PICU, 15.2% were complicated by a PPE of which 28% required the placement of a chest drain. Statistically significant association was found between CRP levels and each of these outcomes (P < .001). Incorporating CRP within a multivariate prediction model provided an area under the curve of up to 0.96. CONCLUSION: CRP can be a useful prognostic marker when evaluating a patient with suspected bacterial pneumonia and could help the paediatrician in identifying patients needing closer follow-up.

Supraglottoplasty for severe laryngomalacia. Can we predict success?

OBJECTIVES: Laryngomalacia is the dynamic collapse of supraglottic structures during inspiration, leading to a variable degree of airway obstruction. Clinical symptoms appear in the first months of life and are usually mild and resolve by the age of 12-18 months. In severe cases, surgical intervention may be considered. The goal of the study was to review the clinical outcome of pediatric patients who underwent supraglottoplasty for laryngomalacia. MATERIAL AND METHODS: Clinical and demographic data were retrieved from medical records of children diagnosed with laryngomalacia by laryngo-bronchoscopy between 2013 and 2019. Indications, outcome and long-term follow-up were collected from children undergoing surgery. RESULTS: During the study period, 115 children were diagnosed with laryngomalacia. The median age at diagnosis was 3 months. Synchronous airway lesions were diagnosed in 20% of patients. Ten (8.7%) children underwent surgical treatment because of significant respiratory symptoms and/or failure to thrive. Three of them had comorbidities. All otherwise healthy children had significant respiratory and nutritional improvement after surgery while those with comorbidities had less successful outcomes. CONCLUSION: We conclude that in severe cases of laryngomalacia, supraglottoplasty has an important role to play in management. In children with comorbidities, the surgical results may be less successful. Therefore, we recommend that the decision to operate should be individualized, ensuring full disclosure to the family regarding the probable benefit along with the limitations of surgery.

Ibuprofen does not prevent postbronchoscopy fever in children undergoing broncho-alveolar lavage.

BACKGROUND: Fiber-optic bronchoscopy (FOB) of the lower airways is a routine examination performed for investigating varying respiratory complaints in children. A common side effect is a transient high fever on the day of the FOB. Such episodes are usually unrelated to an infectious process but may cause clinical uncertainty and parental anxiety. We have previously shown that a single dose of systemic dexamethasone significantly reduces the rate of fever postbronchoscopy (FPB). RESEARCH QUESTION: To prospectively analyze the effect of a prophylactic dose of ibuprofen upon the FPB. STUDY DESIGN AND METHODS: Children presenting for elective FOB and broncho-alveolar lavage (BAL) were randomized, in a double-blind fashion, to receive a single dose of ibuprofen syrup 10 mg/kg or placebo prior to the procedure. Parents were contacted the next day to record the presence or absence of fever. RESULTS: Sixty-one children were included in the final analysis. Thirty-one children were in the treatment group and 30 in the placebo group. FPB occurred in 40 children (65%). There was no difference in the rate of FPB between placebo (63%) and treatment (67%) groups (P = .717). Fifty (82%) children had a positive BAL culture. Among them, 38 had FPB (76%) compared with only 2 of 11 (18%) of those with negative culture (P = .00026, relative risk 4.18). About 80% of positive cultures grew Haemophilus influenza. There was no significant difference between the number of BALs with a positive culture between the treatment and placebo groups (87% vs 77%, P = .35). CONCLUSION: FPB occurs in around twothirds of children when BAL is performed. Fever occurred significantly more frequently when BAL culture is positive. A single standard dose of the nonsteroidal anti-inflammatory drug ibuprofen administered before a FOB does not prevent FPB.

Does birth season influence the odds for asthma? Large cohort analysis.

BACKGROUND AND OBJECTIVE: Few studies have examined the possibility of a link between birth season and the risk for asthma. Those studies that mainly focused on young children, reached different conclusions regarding both the existence of such a link and the season with the highest risk. The purpose of this study was to reinvestigate the relationship between birth season and asthma in a very large cohort, larger than in all previous studies, focusing on adolescents. METHODS: The medical records of consecutive 17-year-old conscripts, born between 1978 and 1999, undergoing medical evaluation before their military service, were reviewed. The prevalence of asthma among conscripts was calculated according to the season of birth. RESULTS: Data from 6 26 460 males and 4 54 104 females were collected. Asthma prevalence was 6.6% of the males and 5.8% of the females. Asthma prevalence was highest among those born in the summer and was approximately 9% higher in women and 6% higher in men than those born in the winter. Those born in the winter had the lowest prevalence of asthma. June was the birth month with the highest prevalence of asthma in both genders together with September among males. CONCLUSIONS: Being born in the summer, especially in June, is associated with an increased risk of asthma compared with a winter birth among Israeli army conscripts. Further research is required to determine the impact of the season of birth on the risk of asthma in higher risk populations.

Pleural-Based Intrathoracic Cystic Lymphangioma in an Infant Mimicking a Pneumonia.

Cystic lymphangioma is an uncommon benign tumor that occurs primarily in children in the cervical region. We report the first case of a pleural-based cystic lymphangioma in an infant. The patient was admitted for RUL pneumonia. Because of the persistence of the radiographic findings despite clinical improvement, a computed tomography (CT) and a magnetic resonance imaging (MRI) scan were performed. They showed a multiloculated cystic lesion in the superior posterior right hemithorax. A surgical procedure was performed with complete resection of the tumor. Histopathological examination showed a pleural-based intrathoracic multicystic lymphangioma. One year after the surgery, the patient feels well without any sign of recurrence.

The correlation of adenosine challenge test results with subsequent clinical course among young children with suspected asthma: a retrospective cohort study.

AIM: Our aim was to evaluate the correlation of Adenosine monophosphate challenge test (AMP-PCW) results with the patients' subsequent clinical course. METHODS: We performed a 6-year retrospective cohort study of young children with suspected asthma who underwent AMP-PCW test. RESULTS: Fifty four children were included in the study (median age, 50.5 months; range, 26-90). AMP-PCW was positive in 35 (65%) children. During the 3-year follow-up period, among 22 of 35 patients in the positive AMP-PCW group and among 17 of 19 in the negative AMP-PCW group-prophylactic therapy was not changed. Prophylactic therapy was initiated or its dose was escalated in 12 of 13 (92.3%) of the children with a positive AMP-PCW test compared to none of the children with a negative challenge test (P < 0.001). Prophylactic therapy was discontinued in only one (7.6%) of the children with a positive test as compared to two (100%) of the children with a negative test (P < 0.001). There were significantly fewer severe asthma exacerbations during a 3-year follow-up period after the challenge test as compared to the preceding 3-year period both in children with a positive (from 34 to 9 total events, P = 0.01) or a negative challenge test (from 16 to 0 events P = 0.01). The severity of airway hyper responsiveness was found to associate with the number of severe asthma exacerbations (P = 0.04) and with a diagnosis of asthma during the following 3 years (P = 0.02). CONCLUSIONS: AMP-PCW test results correlates with the subsequent clinical course of young children with suspected asthma performing the test.

Failure to conceive in women with CF is associated with pancreatic insufficiency and advancing age.

OBJECTIVE: The causes of subfertility in women with CF though multifactorial are not well described. Our aim in this study was to determine the prevalence and factors associated with female subfertility among women with CF. METHODS: A retrospective multinational study from 11 CF centers in 5 countries (Israel, France, Spain, Italy, UK) including women with CF was undertaken. Sub/infertility was defined as not achieving a spontaneous pregnancy after one year of unprotected sexual intercourse. Data including genetics, pancreatic insufficiency (PI), prevalence of diabetes (CFRD), lung function, nutritional status measured by body mass index (BMI), sputum bacterial colonization, and rate of pulmonary exacerbations were collected from patients' files. RESULTS: Out of 605 women, 241 attempted pregnancy. Of these, 84 (35%) had subfertility, and 67 of them eventually became pregnant. Females attempting conception were older but had better pulmonary function and nutrition compared to those who did not. In a multivariate analysis, PI (OR 1.9 [1.03-3.5], p = .04) and older age (OR 3.9 [2.1-7.3] p < .0001) were associated with subfertility. Lung function, BMI, CFRD, Presence of two class I-III mutations and number of exacerbations in the year prior to fertility attempts were not associated with subfertility. CONCLUSIONS: The prevalence of subfertility among women with CF (35%) is higher than the expected 5-15% subfertility in the general population. Older age and pancreatic insufficiency are associated with subfertility in women with CF.

Factors Associated with Positive Adenosine Challenge Test in Young Children with Suspected Asthma.

Background: To investigate the predictive factors associated with positive adenosine monophosphate challenge using the auscultation method (AMP-PCW) test results. Methods: This is a prospective study of young children with suspected asthma who underwent AMP-PCW test. Patients with a positive AMP-PCW test were compared with those with a negative AMP-PCW. A multivariate logistic regression model was performed to identify the independent determinants of positive AMP-PCW. Results: A total of 159 patients completed the AMP-PCW test. The median age was 53 months. In total, 54.0% of patients had a positive AMP-PCW. The prevalence of atopic dermatitis and family history of asthma and allergy were significantly higher among the positive AMP-PCW group (P = 0.04, P = 0.02, and P = 0.007, respectively), as were the prevalences of elevated immunoglobulin E (IgE), peripheral blood eosinophils percentage (P = 0.003, P < 0.001, respectively), and number of emergency department (ED) visits/hospitalizations before AMP-PCW test (P = 0.006). A significant inverse correlation exists between peripheral blood eosinophils percentage and serum IgE levels with the AMP end-point concentrations (r = -0.302, P = 0.001, and r = -0.312, P = 0.001, respectively). In multivariate logistic regression model, peripheral blood eosinophils percentage, IgE levels, and the number of ED visits/hospitalizations before the AMP-PCW test were found as independent predictors for positive AMP-PCW test result. Conclusions: Our results suggest that bronchial responsiveness to AMP-PCW is related to proxy markers of airway inflammation (elevated eosinophils and IgE levels) and clinical exacerbation of asthma before the test. This may support the role of AMP-PCW in detecting inflammatory changes and monitoring their trend among young children with suspected asthma.

Sex-linked difference in blood oxygen saturation.

BACKGROUND: It is not known whether SpO2 in healthy volunteers is affected by sex. OBJECTIVE: To evaluate whether there are differences in SpO2 between young healthy adult males and females and to evaluate whether the differences are already present at birth. METHODS: We studied two cohorts of patients. The first one consisted of young adult volunteers (105 males and 102 females). In these patients, SpO2 was measured as well as selected anthropometric variables (height, weight), vital signs (respiratory rate, pulse rate and body temperature) and obtained data on menstrual cycle phase of the female participants. For the second cohort, we reanalyzed data from a previous prospective study that was performed to compare SpO2 of newborns infants born at different altitudes (sea level or 760 m above sea level). MEASUREMENTS AND MAIN RESULTS: In young male adults, mean SpO2 was 97.1% ± 1.2% versus 98.6% ± 1.0% in females (P < .001). This difference remained significant (P = .002) after correction for BMI, BSA and age, variables that were significantly different between sexes in univariate analysis. The SpO2 in females was unaffected by menstrual phase. In contrast to findings in adults, there were no significant differences in SpO2 measurements in newborn infants attributable to sex. CONCLUSIONS: Healthy young female adults have a higher (1.5%) SpO2 than their male counterparts. This difference is not yet present at birth. Further studies are needed to determine the timing of sex-differences, and to better define the mechanism(s) behind this observation.