Spectrally flat mid-infrared supercontinuum pumped by a high power 2 µm noise-like pulse.

We demonstrate spectrally flat high-power mid-infrared supercontinuum (MIR SC) generation with record-breaking power of 33.1 W and power conversion efficiency of 75.06%. It is pumped by a 2 µm master oscillator power amplifier system consisting of a figure-8 mode-locked noise-like pulse seed laser and dual-stage Tm-doped fiber amplifiers with repetition rate of 4.08 MHz. Through cascading a piece of ZBLAN fiber with 13.5 µm large core diameter by direct-low-loss fusion splicing, SCs with spectral ranges of 1.9-3.68 µm, 1.9-3.84 µm, 1.9-4.02 µm and average powers of 33.1 W, 29.8 W, 25.9 W are generated. To the best of our knowledge, all of them have achieved the highest output power under the same condition of MIR spectrum range. This high-power all-fiber MIR SC laser system has relatively simple architecture, high efficiency and flat spectrum, demonstrating the advantages of 2 µm noise-like pulse pump in high-power MIR SC generation.

Efficacy of cataract surgeries performed during blindness prevention programs in Chongqing, China: a multicenter prospective study.

OBJECTIVE: To determine the efficacy of cataract surgeries in blindness prevention programs in Chongqing. METHODS: During February-December 2019, we prospectively enrolled 487 patients (592 eyes) undergoing cataract surgery during blindness prevention programs in 6 Chongqing district/county hospitals (experimental group) and 481 patients (609 eyes) undergoing cataract surgery in the First Affiliated Hospital of Chongqing Medical University (controls). Uncorrected visual acuity (UCVA), refractive status, best corrected visual acuity (BCVA), slit lamp examination, and visual function/quality of life (VF-QOL) questionnaire scores were evaluated preoperatively, and at 1 and 6 months postoperatively. RESULTS: In the experimental group, UCVA, BCVA, and VF-QOL scores at 1 and 6 months were better than the preoperative values (P < 0.05), but lower than the control-group values (P < 0.05). Rates of good UCVA and BCVA outcomes (≤ 0.5 logMAR) in the experimental group were 76.2% and 87.6%, respectively, at 1 month and 68.9% and 83.1%, respectively, at 6 months. Most eyes in the experimental (82.1%) and control (89.5%) groups had refractive errors within ± 1 D at 1 month. At 6 months, posterior capsule opacification (PCO) was more common in the experimental group (20.9% vs. 15.0%, P < 0.05). At 6 months, the main causes of visual impairment (UCVA > 0.5 logMAR) in the experimental group were uncorrected refractive errors (33.0%), PCO (29.5%), and fundus diseases (33.9%). CONCLUSION: Cataract surgeries in blindness prevention programs in Chongqing significantly improved visual acuity, VF, and QOL, but underperformed compared to surgeries in the tertiary teaching hospital.

2.1 µm, 1.52 µJ square-wave noise-like pulse from an all-fiber figure-of-9 Ho-doped oscillator and single-stage amplifier.

A 2.1 µm, high energy square-wave noise-like pulse (NLP) in an all-fiber Ho-doped fiber laser is proposed, which consists of an oscillator and a single-stage amplifier. In the figure-of-9 oscillator, mode-locking is achieved based on the nonlinear amplifying loop mirror, employing a long gain fiber to provide sufficient gain in 2.1 µm band and optimizing the cavity length to obtain maximum pulse energy output. With appropriate pump power and polarization state, the oscillator emits a 175.1 nJ square-wave NLP with center wavelength of 2102.2 nm and spike width of 540 fs. The 3-dB spectral width and pulse envelope width are 11.2 nm and 6.95 ns, respectively. The single-stage amplifier employs a bi-directional pump scheme. After amplification, 5.8 W NLP with a slope efficiency of 56.8% is obtained. The pulse energy of NLP is scaled to 1.52 µJ, which is the highest pulse energy of NLP at 2.1 µm to the best of our knowledge. The obtained high-energy square-wave NLP-fiber laser has great potential in mid-infrared laser generation.

Hectowatt-level GHz burst-mode all-fiber laser based on dissipative soliton resonance.

We demonstrate a high power Yb-doped burst-mode all-fiber laser system operating at GHz intra-burst repetition rate. To our knowledge, it is the first report utilizing dissipative soliton resonance (DSR) to generate tunable burst-mode rectangular pulses. Due to the tunable duration and the rapid rise/fall time for DSR pulses, a 1-10 ns adjustable burst pulse duration is achieved. The intra-burst with sinusoidal waveform can be tuned from 0.8 GHz to 1.5 GHz and actively modulated by an electro-optic modulator (EOM). Amplified by a three-stage Yb-doped fiber amplifier (YDFA), the output power achieves 304 W at 10 ns of burst duration, and the maximum peak power reaches over 50 kW at 2 ns of burst duration. This laser system is anticipated to be applied to generate high power arbitrary microwave signal.

Effect of ambient temperature on outpatient admission for osteoarthritis and rheumatoid arthritis in a subtropical Chinese city.

BACKGROUND: Current findings on the impact of weather conditions on osteoarthritis (OA) and rheumatoid arthritis (RA) are sparse and not conclusive. This study aimed to investigate the relationship between temperature change and OA/RA admission. METHODS: Daily OA/RA admission, meteorological data and pollutants from 1 January 2014 to 31 December 2017 in Hefei, China, were collected. We quantified the relationship between ambient temperature and OA/RA admission using a distributed lag nonlinear model (DLNM). Stratified analyses by gender and age were also examined. RESULTS: Temperature decrease was significantly associated with RA admission (25th percentile of temperature versus 50th percentile of temperature), with the acute and largest effect at current days lag (RR: 1.057, 95%CI: 1.005-1.111). However, no significant association between temperature and OA admission was observed. When conducting subgroup analyses by individual characteristics, we found that females and patients aged 41-65 years were more vulnerable to temperature decrease than males, patients aged 0-40 and ≧66 years, respectively. CONCLUSIONS: This study suggested that temperature decrease was a risk factor for increases in RA admission. Females and patients aged 41-65 years were particularly vulnerable to the effect of temperature decrease.

Pulse evolution and multi-pulse state of coherently coupled polarization domain walls in a fiber ring laser.

Pulse evolution and multi-pulse state of coherently coupled polarization domain walls (PDW) is experimentally demonstrated in a novel fiber ring laser. Versatile pulse shapes benefit by wide range moving of PDW in the weakly birefringent fiber. The 8.6 m short-cavity structure is more compact and accessible based on a 976 nm pump with nearly zero negative dispersion (-0.0002 ps2). Besides, multi-pulse patterns such as PDW splitting, harmonic mode-locking, and periodic soliton collision are also observed under larger net negative dispersion (-3.09 ps2) and 151m-longer cavity. This is the first demonstration of coherently coupled PDW in a fiber laser using a bandpass filter and the formation of coherently coupled PDW is ascribed to the BPF's force filtering.

Novel coronavirus (SARS-CoV-2) infection in a renal transplant recipient: Case report.

An ongoing outbreak of pneumonia associated with the severe acute respiratory coronavirus 2 (SARS-CoV-2) started in Wuhan, China, with cases now confirmed in multiple countries. The clinical course of patients remains to be fully characterized, clinical presentation ranges from asymptomatic infection to acute respiratory distress syndrome and acute renal failure, and no pharmacological therapies of proven efficacy yet exist. We report a case of SARS-CoV-2 infection in a renal transplant recipient with excellent outcome. This case states the importance of close monitoring of the concentration of cyclosporine in patients treated with lopinavir/ritonavir; the routine treatment of corticosteroid can be continued. This is a rare report of SARS-CoV-2 infection in a renal transplant recipient. Further data are needed to achieve better understanding of the impact of immunosuppressive therapy on the clinical presentation, severity, and outcome of SARS-CoV-2 infections in solid organ transplant recipients.

Durational effect of particulate matter air pollution wave on hospital admissions for schizophrenia.

BACKGROUND: Short-term exposure to high level of ambient particulate matters (PM) concentrations has been linked with increased hospital admissions (HA) for schizophrenia. However, evidence is inconclusive about the added effect of multi-day exposure to high-level PM concentration on schizophrenia. This study aims to evaluate the durational effect of PM air pollution wave on schizophrenia. METHOD: Data on daily HA for schizophrenia, PM (PM2.5 and PM10) and meteorological variables over the period of 2014-2017 was collected in Jining, Shandong, China. Air pollution wave of PM was defined as ≥2 or ≥3 or ≥4 consecutive days with PM concentration ≥90th or ≥92.5th or ≥95th or ≥97.5th percentiles, respectively. A time-series Poisson regression model with duration as the variable of interest was used to evaluate the associations of PM air pollution wave with HA for schizophrenia. RESULTS: A total of 14650 hospital admissions for schizophrenia were identified. Under various air pollution wave definitions, both PM2.5 and PM10 had significant adverse effects on schizophrenia HA. PM2.5 wave defined as ≥2 consecutive days with concentration ≥90th, ≥92.5th, ≥95th and ≥97.5th percentile was associated with 4.8% (2.0%-7.6%), 4.9% (1.9%-7.9%), 5.5% (2.0%-9.2%), and 7.6% (2.9%-12.6%) increase of HA for schizophrenia at lag 6. PM2.5 waves defined as ≥3 consecutive days with concentration ≥90th, ≥92.5th, ≥95th and ≥97.5th percentile respectively corresponded to 5.0% (2.3%-7.8%), 5.1% (1.9%-8.4%), 6.9% (3.0%-10.8%) and 12.0% (5.3%-19.1%) increases in HA for schizophrenia at lag 6. The most significant associations were observed on the sixth day in different lag models. CONCLUSIONS: PM air pollution wave was associated with increased risk of hospital admissions for schizophrenia, with stronger associations among married and female patients.

Switchable generation of a sub-200 fs dissipative soliton and a noise-like pulse in a normal-dispersion Tm-doped mode-locked fiber laser.

We report on the switchable generation of a dissipative soliton (DS) pulse and a noise-like pulse (NLP) in an all-fiberized Tm-doped fiber laser in the normal-dispersion region. Mode-locking operation is achieved through a nonlinear polarization rotation component, and the cavity dispersion is compensated using ultra-high numerical aperture (UHNA4) fiber that is easy to integrate and low in cost. At a pump threshold of 510 mW, DS operation can first be achieved without additional filter. The 3 dB spectrum bandwidth of the DS pulse is greater than 50 nm, and the duration of the de-chirped pulse is 193 fs. By increasing the pump power to 880 mW, the mode-locking state can evolve into NLP operation with proper cavity polarization state. The 3 dB spectrum bandwidth and duration of de-chirped coherence spike are 105.6 nm and 121 fs, respectively. Meanwhile, ultra-broadband NLP (over 150 nm considering 3 dB spectrum width) can also be observed with the appropriate cavity parameters. All the proposed pulse patterns present good capacity for achieving narrow pulse width and withstanding high pulse energy.

Impact of temperature variability on childhood allergic rhinitis in a subtropical city of China.

BACKGROUND: Many studies have shown an association of childhood respiratory diseases with short-term temperature variability such as diurnal temperature range (DTR) and temperature change between two neighboring days (TCN). However, the impact of temperature variability on allergic rhinitis (AR) has not been investigated so far. This study sought to evaluate the short-term effect of temperature variability (i.e., TCN and DTR) on AR, as well as to identify vulnerable subpopulations. METHOD: We collected daily data on emergency room visits and outpatients for AR and weather variables in Hefei, China during 2014-2016. A distributed lag non-linear model that controlled for long-term trend and seasonality, mean temperature, relative humidity, day of week was used to fit the associations of AR with DTR and TCN. Stratified analyses by age, sex and occupation were also performed. RESULTS: During the study period, there were a total of 53,538 cases and the average values of DTR and TCN were 8.4 °C (range: 1.0 °C to 21.2 °C) and 0 °C (range: - 12.2 °C to 5.9 °C), respectively. While we did not observe an adverse effect of DTR on AR, TCN was significantly associated with increased risk of AR. Specifically, a large temperature drop between two adjacent days (3.8 °C, 5th percentile of TCN) has a delayed and short-lasting effect on AR, with the estimated relative risk of 1.02 (95% confidence interval: 1.01 to 1.04) at lag 12. Moreover, boys and children older than 15 years seemed to be more vulnerable to the effect of TCN. CONCLUSIONS: This study provided evidence of an adverse effect of large temperature drops between two adjacent days on childhood AR. Attention paid to boys and older children may help prevent AR attacks.

The short-term association between air pollution and childhood asthma hospital admissions in urban areas of Hefei City in China: A time-series study.

BACKGROUND: The impacts of air pollution on asthma attacks have become a hotspot. Previous studies mainly focused on the developed countries or cities. There have been very limited studies in less-developed region to quantify the effects of air pollutants on asthma admissions in children. This study aims to assess the short-term impact of air pollutants on asthma hospital admissions for children in Hefei, China. METHODS: Poisson generalized linear regression combined with distributed lag non-linear model (DLNM) were applied to investigate the effects of air pollutants on daily childhood hospital admissions of asthma from 2015 to 2016, controlling for meteorological factors. Subgroup analyses by sex and age were performed. RESULTS: There were a total of 17,227 asthma admissions during 2015-2016. We found positive correlations between childhood asthma hospital visits and concentrations of NO2, O3, PM10 and PM2.5. Significantly, NO2 exhibited robust positive correlations with cumulative effects 1.551 (95% CI: 1.306-1.841, lag0-3 days) in single-pollutant model and 1.580 (95% CI: 1.315-1.899, lag0-3 days) in multiple-pollutant model. CONCLUSIONS: Air pollutants had adverse effects on childhood asthma. NO2 presented the greatest effect, followed by PM2.5. Results will be important for health authority and guardians to realize the severity of air pollution on the increased risk of asthma, so as to develop relevant strategies and health interventions to meet the challenges of childhood asthma and reduce air pollution.

Risk effects of high and low relative humidity on allergic rhinitis: Time series study.

BACKGROUND: The relationship between environmental factors and allergic rhinitis (AR) has become a focal point recently. However, few studies have investigated the adverse effects of both high relative humidity (RH) and low relative humidity. Moreover, the laged effect and disease burden of RH on AR were also neglected. OBJECTIVES: To explore the association of both high and low RH on daily AR hospital outpatients, and to quantify the corresponding disease burden attributable to RH. METHODS: In our study, we define 95th as high RH and 5th as low RH. A distributed lag non-linear model (DLNM) combined with a Poisson generalized linear regression model were applied to analyze the relationship between RH and hospital outpatients for AR. All patients were retrieved from Anhui Provincial Children's Hospital (n = 37,221) from January 2015 to December 2016. Daily meteorological and air pollutant data were collected by Hefei Meteorological Bureau and Environmental Protection Agency. Subgroup analyses were conducted by gender and occupational groups. RESULTS: Acute adverse effects of high and low RH on AR were explored respectively, with an increase of daily AR outpatients when encountered high and low RH. The low RH presented a risk effect at current day and lasted up to the eighth day. However, high RH began to appear a risk effect on the fourth day. Notably, the fraction of hospital outpatients attributable to low RH was 5.22% (95% CI: 1.92%, 8.33%) and high RH was 4.07% (95% CI: 1.13%, 7.30%) in the backward perspective. Additionally, male and students apparent to be more sensitive to the effects of low RH. CONCLUSION: This study suggests that both high and low RH are potential trigger for AR hospital outpatients in Hefei, China. Our studies might offer valuable messages to health practitioners and useful direction to decisions-makers respectively.

Self-organized structures of bound states in a 2 µm dispersion-managed mode-locked fiber laser.

We report on the experimental generation of various self-organized structures of bound states in a near zero-dispersion mode-locked fiber laser. When the pump power is fixed at 492 mW, appropriately adjusting polarization controllers, the switching of the cavity feedback results in the evolution from the single pulse to the dispersion-managed soliton (i.e., stretched-pulse) pair. With the increase of pump power, bound states composed of more than two pulses can also be observed. Our results of the self-organized structures might enlarge the data-carrying capacity of current fiber-optical communication systems and benefit the investigation of nonlinear dynamics of bound states in fiber lasers at 2 µm.

Observation of sub-400fs, wavelength-switchable stretched pulse and bound-state pulse in Tm-doped fiber laser.

We report on the experimental observation of wavelength-switchable stretched pulse and bound-state pulse in a dispersion-managed Tm-doped laser. At a pump power of 572 mW, a stretched pulse with a pulse duration of 389 fs can be first obtained at 1961 nm. By increasing the pump power and appropriately adjusting the cavity polarization state, the mode-locking wavelength can be switched from 1961 nm to 1980 nm caused by the birefringence filtering effect based on nonlinear polarization rotation, and the corresponding pulse duration is 371 fs. Meanwhile, loosely bound states of two pulses and three pules at 1980 nm can be observed with appropriate cavity parameters.

Sequence analysis-based characterization and identification of neurovirulence-associated variants of 36 EV71 strains from China.

Enterovirus 71 (EV71) is the main pathogen of hand-foot-mouth disease (HFMD) and causes several neurological complications. As new strains of EV71 are constantly discovered, it is important to understand the genomic characteristics of the viruses and the mechanism of virulence. Herein, we isolated five strains of EV71 from HFMD patients with or without neurovirulence and sequenced their whole genomes. We then performed whole genome sequence analysis of totally 36 EV71 strains. The phylogenetic analysis of the VP1 region revealed all five isolated strains are clustered into C4a of C4 subgenotype. In addition, by comparing the complete genome sequences of 36 strains, 253 variable amino acid positions were found, 14 of which were identified to be associated with neurovirulence (P < 0.05). Moreover, a similar pattern of amino acid variants combination was identified in four strains without neurovirulence, indicating this type of variant pattern might be associated with avirulence. The strains with neurovirulence appeared to be distinguished from those without neurovirulence by the variants in VP1 and P2 regions, implying VP1 and P2 are the important regions associated with neurovirulence. Indeed, 3-D modeling of VP1 and P2 regions of non-neurovirulent and neurovirulent strains revealed that the different variants resulted in different protein structures and amino acid composition of ligand binding site, which might account for their difference in neurovirulence. In summary, our study reveals 14 variable amino acid positions of VP1, P2 and P3 regions are related to the virulence and that mutations in the capsid proteins of EV71 might contribute to neurovirulence.

Impact of short-term temperature variability on emergency hospital admissions for schizophrenia stratified by season of birth.

Diurnal temperature range (DTR) and temperature change between neighboring days (TCN) are important meteorological indicators closely associated with global climate change. However, up to date, there have been no studies addressing the impacts of both DTR and TCN on emergency hospital admissions for schizophrenia. We conducted a time-series analysis to assess the relationship between temperature variability and daily schizophrenia onset in Hefei, an inland city in southeast China. Daily meteorological data and emergency hospital admissions for schizophrenia from 2005 to 2014 in Hefei were collected. After stratifying by season of birth, Poisson generalized linear regression combined with distributed lag nonlinear model (DLNM) was used to examine the relationship between temperature variability and schizophrenia, adjusting for long-term trend and seasonality, mean temperature, and relative humidity. Our analysis revealed that extreme temperature variability may increase the risk for schizophrenia onset among patients born in spring, while no such association was found in patients born in summer and autumn. In patients born in spring, the relative risks of extremely high DTR comparing the 95th and 99th percentiles with the reference (50th, 10 °C) at 3-day lag were 1.078 (95 % confidence interval (CI) 1.025-1.135) and 1.159 (95 % CI 1.050-1.279), respectively. For TCN effects, only comparing 99th percentile with reference (50th, 0.7 °C) was significantly associated with emergency hospital admissions for schizophrenia (relative risk (RR) 1.111, 95 % CI 1.002-1.231). This study suggested that exposure to extreme temperature variability in short-term may trigger later days of schizophrenia onset for patients born in spring, which may have important implications for developing intervention strategies to prevent large temperature variability exposure.

Impact of weather factors on hand, foot and mouth disease, and its role in short-term incidence trend forecast in Huainan City, Anhui Province.

Hand, foot, and mouth disease (HFMD) is one of the most common communicable diseases in China, and current climate change had been recognized as a significant contributor. Nevertheless, no reliable models have been put forward to predict the dynamics of HFMD cases based on short-term weather variations. The present study aimed to examine the association between weather factors and HFMD, and to explore the accuracy of seasonal auto-regressive integrated moving average (SARIMA) model with local weather conditions in forecasting HFMD. Weather and HFMD data from 2009 to 2014 in Huainan, China, were used. Poisson regression model combined with a distributed lag non-linear model (DLNM) was applied to examine the relationship between weather factors and HFMD. The forecasting model for HFMD was performed by using the SARIMA model. The results showed that temperature rise was significantly associated with an elevated risk of HFMD. Yet, no correlations between relative humidity, barometric pressure and rainfall, and HFMD were observed. SARIMA models with temperature variable fitted HFMD data better than the model without it (sR 2 increased, while the BIC decreased), and the SARIMA (0, 1, 1)(0, 1, 0)52 offered the best fit for HFMD data. In addition, compared with females and nursery children, males and scattered children may be more suitable for using SARIMA model to predict the number of HFMD cases and it has high precision. In conclusion, high temperature could increase the risk of contracting HFMD. SARIMA model with temperature variable can effectively improve its forecast accuracy, which can provide valuable information for the policy makers and public health to construct a best-fitting model and optimize HFMD prevention.

Impacts of temperature change on ambulance dispatches and seasonal effect modification.

Ambulance dispatch is a proxy of acute health outcomes, and growing epidemiological evidence documented its relation to extreme temperature events. Research, however, on short-term temperature change and ambulance dispatches is scarce. We aimed to investigate the effect of short-term temperature change on ambulance dispatches and potential modification by season. Daily data on ambulance dispatch and weather factors were collected in Huainan, a Chinese inland city from December 2011 through December 2013. A Poison generalized linear regression model combined with distributed lag nonlinear model was constructed to examine the association of temperature change between neighboring days (TCN) with ambulance dispatches. The effect modification by season was also examined. There were 48,700 ambulance attendances during the study period. A statistically significant association of TCN with ambulance dispatches was observed. Temperature rise between neighboring days (TCN > 0) was associated with elevated adverse risk of ambulance dispatches, and the effects appeared to be acute (lag0, on the current day) and could last for at least a week, while temperature drop between neighboring days (TCN < 0) had a protective effect. For a 1 °C increase of TCN at lag0 and lag06 (on the 7-day moving average), the risk of ambulance dispatches increased by 2 % (95 % CI 1-3 %) and 7 (95 % CI 1-13 %), respectively. Extreme TCN increase (95th percentile, 3.3 °C vs. 0 °C) at lag0 and lag05 was accompanied by 6 (95 % CI 3-8 %) and 27 % (95 % CI 12-44 %) increase in ambulance dispatches. Ambulance dispatches were more vulnerable to extremely great temperature rise in summer and autumn. TCN was adopted for the first time to quantify the impact of short-term temperature change on ambulance dispatches. Temperature drop between neighboring days (TCN < 0) had a protective effect on ambulance dispatches, while temperature rise between neighboring days (TCN > 0) could acutely trigger the increase in ambulance dispatches, and TCN effect differs by season.

Asthma and Risk of Stroke: A Systematic Review and Meta-analysis.

BACKGROUND: Several studies have suggested that asthma is associated with an increased risk of stroke. However, the results are inconsistent. The aim of this study is to investigate the relation of asthma and the risk of stroke through a systematic review and meta-analysis of published research. METHODS: Pertinent studies were identified by a search of the PubMed and the Web of Science databases to June 2015. Study-specific hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled using fixed-effect or random-effect models when appropriate. Associations were tested in subgroups representing different participants and study characteristics. Publication bias was assessed with Egger's test. RESULTS: Five articles comprising 524,637 participants and 6031 stroke cases were eligible for inclusion. Asthma was associated significantly with increased risk of stroke, and the pooled HR was 1.32 (95% CI: 1.13, 1.54, I(2)=80.4%). Subgroup analyses revealed that the association between asthma and stroke risk was stronger among female patients (HR = 1.42, 95% CI: 1.15-1.76) and prospective cohort study design (HR = 1.52, 95% CI: 1.21-1.91). CONCLUSION: Asthma is associated with a significantly increased risk of stroke. This finding may have clinical and public health importance.

Prenatal antibiotic use and risk of childhood wheeze/asthma: A meta-analysis.

BACKGROUND: Existing body of knowledge suggests that antibiotic use during pregnancy was inconsistently associated with childhood wheeze/asthma. The aim of this study was to determine whether exposure to antibiotic during pregnancy could increase the risk for childhood wheeze/asthma using a comprehensive meta-analysis. METHODS: PubMed, MEDLINE, and China National Knowledge Infrastructure (CNKI) were systematically searched for studies up to September 10, 2014, and additional studies were found by searching reference lists of relevant articles. For this meta-analysis, cohort studies and case-control studies assessing the association between antibiotic use during pregnancy and risk of childhood wheeze/asthma were included. Extracted data were mainly pooled using random-effects model. Study quality was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). RESULTS: Ten studies were identified in final analysis. Pooling analysis of these studies showed an OR of 1.20 (95% CI, 1.13-1.27) for wheeze/asthma. After excluding case-control studies and prospective studies without achieving high scores on the NOS, the pooled OR was 1.18 (95% CI, 1.11-1.26). We found the risk of antibiotic use and pooled ORs of wheeze/asthma were 1.09 (95% CI, 0.92-1.29) for the first trimester, 1.14 (95% CI, 1.01-1.29) for the second trimester, and 1.33 (95% CI, 1.11-1.60) for the third trimester, respectively. CONCLUSIONS: This meta-analysis suggests that antibiotic exposure during pregnancy may increase the risk of wheeze/asthma in childhood. Besides, the risk of developing wheeze/asthma in childhood was marked during last two trimesters of pregnancy. Future studies of large-size and prospective cohorts which adequately address concerns for confounder bias are needed to examine the relationship between antibiotic use and risk of childhood asthma.