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Liu Y, Yang Y, Zhao C, Liu M, Xu D, Wu H, Lei J, Deng Y, Xie W, Huang J, Wu S, Zhang Y, Zhang H, He Y, Peng Z, Wang Y, Shen H, Wang Q, Zhang Y, Yan D, Wang L, Ma X. An immune window of opportunity to prevent spontaneous abortion: prepregnancy peripheral leukocytes and subsets were associated with a decreased risk of spontaneous abortion. Hum Reprod 2024; 39:326-334. [PMID: 38166353 DOI: 10.1093/humrep/dead261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 11/17/2023] [Indexed: 01/04/2024] Open
Abstract
STUDY QUESTION Do prepregnancy peripheral leukocytes (PPLs) and their subsets influence the risk of spontaneous abortion (SAB)? SUMMARY ANSWER PPLs and their subsets are associated with the risk of SAB. WHAT IS KNOWN ALREADY Compelling studies have revealed the crucial role of maternal peripheral leukocytes in embryo implantation and pregnancy maintenance. Adaptive changes are made by PPLs and their subsets after conception. STUDY DESIGN, SIZE, DURATION This population-based retrospective cohort study was based on data from the National Free Pre-pregnancy Check-up Project (NFPCP) in mainland China. Couples preparing for pregnancy within the next six months were provided with free prepregnancy health examinations and counseling services for reproductive health. The current study was based on 1 310 494 female NFPCP participants aged 20-49 who became pregnant in 2016. After sequentially excluding 235 456 participants lost to follow-up, with multiple births, and who failed to complete blood tests, a total of 1 075 038 participants were included in the primary analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS PPLs and their subset counts and ratios were measured. The main outcome was SAB. A multivariable logistic regression model was used to estimate the odds ratio (OR) and 95% CI of SAB associated with PPLs and their subsets, and restricted cubic spline (RCS) was used to estimate the nonlinear exposure-response relationship. MAIN RESULTS AND ROLE OF CHANCE Of the included pregnant participants, a total of 35 529 SAB events (3.30%) were recorded. Compared to participants with reference values of PPLs, the ORs (95% CIs) of leukopenia and leukocytosis for SAB were 1.14 (1.09-1.20) and 0.74 (0.69-0.79), respectively. The RCS result revealed a monotonous decreasing trend (Pnonlinear < 0.05). Similar relationships were observed for the neutrophil count and ratio, monocyte count, and middle-sized cell count and ratio. The lymphocyte ratio showed a positive and nonlinear relationship with the risk of SAB (Pnonlinear < 0.05). Both eosinophils and basophils showed positive relationships with the risk of SAB (eosinophil Pnonlinear > 0.05 and basophil Pnonlinear < 0.05). LIMITATIONS, REASONS FOR CAUTION Chemical abortion events and the cause of SAB were not collected at follow-up. Whether women with abnormal PPLs had recovered during periconception was not determined. WIDER IMPLICATIONS OF THE FINDINGS PPLs and their subsets are associated with the risk of SAB. Leukopenia and neutropenia screening in women preparing for pregnancy and developing a feasible PPL stimulation approach should be emphasized to utilize the immune window of opportunity to prevent SAB. STUDY FUNDING/COMPETING INTEREST(S) This study was approved by the Institutional Research Review Board of the National Health and Family Planning Commission. This study was supported by the National Key Research and Development Program of China (grants 2021YFC2700705 [Y.Y.] and 2016YFC100307 [X.M.]) and the National Natural Science Foundation of China (grant no. 82003472 [L.W.]). The funding source was not involved in the study design, data collection, analysis and interpretation of the data, writing the report, or the decision to submit this article for publication. No competing interests. TRIAL REGISTRATION NUMBER N/A.
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Affiliation(s)
- Youhong Liu
- Institute of Epidemiology and Statistics, School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Ying Yang
- National Research Institute for Family Planning, Beijing, China
- National Human Genetic Resources Centre, Beijing, China
- Graduate School of Peking Union Medical College, Beijing, China
| | - Chuanyu Zhao
- National Research Institute for Family Planning, Beijing, China
- National Human Genetic Resources Centre, Beijing, China
- Graduate School of Peking Union Medical College, Beijing, China
| | - Meiya Liu
- Institute of Epidemiology and Statistics, School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Die Xu
- Institute of Epidemiology and Statistics, School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Hanbin Wu
- National Research Institute for Family Planning, Beijing, China
- National Human Genetic Resources Centre, Beijing, China
| | - Jueming Lei
- National Research Institute for Family Planning, Beijing, China
- National Human Genetic Resources Centre, Beijing, China
| | - Yuzhi Deng
- National Research Institute for Family Planning, Beijing, China
- National Human Genetic Resources Centre, Beijing, China
| | - Wenlu Xie
- Institute of Epidemiology and Statistics, School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Jiaxin Huang
- Institute of Epidemiology and Statistics, School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Siyu Wu
- Institute of Epidemiology and Statistics, School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Ya Zhang
- National Research Institute for Family Planning, Beijing, China
| | - Hongguang Zhang
- National Research Institute for Family Planning, Beijing, China
| | - Yuan He
- National Research Institute for Family Planning, Beijing, China
| | - Zuoqi Peng
- National Research Institute for Family Planning, Beijing, China
| | - Yuanyuan Wang
- National Research Institute for Family Planning, Beijing, China
| | - Haiping Shen
- Department of Maternal and Child Health, National Health Commission of the PRC, Beijing, China
| | - Qiaomei Wang
- Department of Maternal and Child Health, National Health Commission of the PRC, Beijing, China
| | - Yiping Zhang
- Department of Maternal and Child Health, National Health Commission of the PRC, Beijing, China
| | - Donghai Yan
- Department of Maternal and Child Health, National Health Commission of the PRC, Beijing, China
| | - Long Wang
- Institute of Epidemiology and Statistics, School of Public Health, Lanzhou University, Lanzhou, Gansu, China
| | - Xu Ma
- National Research Institute for Family Planning, Beijing, China
- National Human Genetic Resources Centre, Beijing, China
- Graduate School of Peking Union Medical College, Beijing, China
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Nealon J, Derqui N, de Courville C, Biering-Sørensen T, Cowling BJ, Nair H, Chaves SS. Looking back on 50 years of literature to understand the potential impact of influenza on extrapulmonary medical outcomes. Open Forum Infect Dis 2022; 9:ofac352. [PMID: 35937650 PMCID: PMC9350618 DOI: 10.1093/ofid/ofac352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/20/2022] [Indexed: 11/30/2022] Open
Abstract
We conducted a scoping review of the epidemiological literature from the past 50 years to document the contribution of influenza virus infection to extrapulmonary clinical outcomes. We identified 99 publications reporting 243 associations using many study designs, exposure and outcome definitions, and methods. Laboratory confirmation of influenza was used in only 28 (12%) estimates, mostly in case-control and self-controlled case series study designs. We identified 50 individual clinical conditions associated with influenza. The most numerous estimates were of cardiocirculatory diseases, neurological/neuromuscular diseases, and fetal/newborn disorders, with myocardial infarction the most common individual outcome. Due to heterogeneity, we could not generate summary estimates of effect size, but of 130 relative effect estimates, 105 (81%) indicated an elevated risk of extrapulmonary outcome with influenza exposure. The literature is indicative of systemic complications of influenza virus infection, the requirement for more effective influenza control, and a need for robust confirmatory studies.
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Affiliation(s)
- Joshua Nealon
- Sanofi , Lyon , France
- School of Public Health, The University of Hong Kong , Hong Kong Special Administrative Region , China
| | - Nieves Derqui
- Sanofi , Lyon , France
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London , UK
| | | | - Tor Biering-Sørensen
- Department of Cardiology, Copenhagen University Hospital - Herlev and Gentofte , Copenhagen , Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Benjamin J Cowling
- School of Public Health, The University of Hong Kong , Hong Kong Special Administrative Region , China
| | - Harish Nair
- Usher Institute, The University of Edinburgh , Scotland , UK
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Roberts NF, Sprague AE, Taljaard M, Fell DB, Ray JG. Maternal-Newborn Health System Changes and Outcomes in Ontario Canada during Wave 1 of the COVID-19 Pandemic - A Retrospective Study. JOURNAL OF OBSTETRICS AND GYNAECOLOGY CANADA 2021; 44:664-674. [PMID: 34973435 PMCID: PMC8716144 DOI: 10.1016/j.jogc.2021.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To determine the population-level impact of COVID-19 pandemic-related obstetric practice changes on maternal and newborn outcomes. METHODS Segmented regression analysis examined changes that occurred 240 weeks pre-pandemic through the first 32 weeks of the pandemic using data from Ontario's Better Outcomes Registry & Network. Outcomes included birth location, length of stay, labour analgesia, mode of delivery, preterm birth, and stillbirth. Immediate and gradual effects were modelled with terms representing changes in intercepts and slopes, corresponding to the start of the pandemic. RESULTS There were 799 893 eligible pregnant individuals included in the analysis; 705 767 delivered in the pre-pandemic period and 94,126 during the pandemic wave 1 period. Significant immediate decreases were observed for hospital births (relative risk [RR] 0.99; 95% CI 0.98-0.99), length of stay (median change -3.29 h; 95% CI -3.81 to -2.77), use of nitrous oxide (RR 0.11; 95% CI 0.09-0.13) and general anesthesia (RR 0.69; 95% CI 0.58- 0.81), and trial of labour after cesarean (RR 0.89; 95% CI 0.83-0.96). Conversely, there were significant immediate increases in home births (RR 1.35; 95% CI 1.21-1.51), and use of epidural (RR 1.02; 95% CI 1.01-1.04) and regional anesthesia (RR 1.01; 95% CI 1.01-1.02). There were no significant immediate changes for any other outcomes, including preterm birth (RR 0.99; 95% CI 0.93-1.05) and stillbirth (RR 1.11; 95% CI 0.87-1.42). CONCLUSION Provincial health system changes implemented at the start of the pandemic resulted in immediate clinical practice changes but no significant increases in adverse outcomes.
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Affiliation(s)
- Nicole F Roberts
- Better Outcomes Registry & Network (BORN) Ontario, Centre for Practice Changing Research, 401 Smyth Rd, Ottawa, ON K1H 8L1.
| | - Ann E Sprague
- Better Outcomes Registry & Network Ontario; Children's Hospital of Eastern Ontario (CHEO) Research Institute 401 Smyth Rd, Ottawa, ON K1H 8L1
| | - Monica Taljaard
- Ottawa Hospital Research Institute, Clinical Epidemiology Program; School of Epidemiology and Public Health, University of Ottawa 451 Smyth Rd, Ottawa, ON K1H 8L1
| | - Deshayne B Fell
- Children's Hospital of Eastern Ontario (CHEO) Research Institute; School of Epidemiology and Public Health, University of Ottawa 401 Smyth Rd, Ottawa, ON K1H 8L1
| | - Joel G Ray
- Department of Obstetrics and Gynecology, St. Michael's Hospital 36 Queen St E, Toronto, ON M5B 1W8
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Brillo E, Tosto V, Giardina I, Buonomo E. Maternal tetanus, diphtheria, and acellular pertussis (Tdap) and influenza immunization: an overview. J Matern Fetal Neonatal Med 2019; 34:3415-3444. [PMID: 31645152 DOI: 10.1080/14767058.2019.1680633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Maternal tetanus, diphtheria, and acellular pertussis (Tdap) and influenza immunization for women during pregnancy (the so-called "maternal immunization") has been introduced in several countries, and recently also in Italy, to protect mother and fetus during pregnancy, infant in his first months of life and mother during postpartum period. However, very low vaccination coverage rates have been reached due to several variables. METHODS A literature search was conducted on PubMed and Embase, including any experimental or observational studies, to assesses existing evidence on the effectiveness, efficacy, safety and optimal timing of administration of Tdap and influenza immunization in pregnancy for mothers and their infants. The search was finalized in August 2019. RESULTS Reviewing the literature, we identified only a few studies that, among several maternal and infant outcomes, found sporadic significant associations with maternal influenza immunization and even less with Tdap immunization. Moreover, most of the authors of these studies explained these findings as a result of residual confounding effect. The effectiveness of maternal influenza immunization is more complicated to prove than the effectiveness of Tdap immunization because of several reasons. Not all nations recommend and offer vaccines in the same weeks of pregnancy and this one manifests the complexity in defining the best timing for Tdap or influenza immunization. CONCLUSIONS The safety of maternal Tdap or influenza immunization is supported by the evidence so far, however, regular surveillance should be maintained, especially with regard to the influenza vaccine that changes in formulation each year. There is a need to optimize the timing of vaccination in pregnancy and to have a national system of detection of maternal immunization in each country.
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Affiliation(s)
- Eleonora Brillo
- Center for Research in Perinatal and Reproductive Medicine, University of Perugia, Perugia, Italy.,Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy
| | - Valentina Tosto
- Department of Obstetrics and Gynecology, University Hospital of Perugia, Perugia, Italy
| | - Irene Giardina
- Center for Research in Perinatal and Reproductive Medicine, University of Perugia, Perugia, Italy.,Department of Obstetrics and Gynecology, University Hospital of Perugia, Perugia, Italy
| | - Ersilia Buonomo
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy
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Dorélien A. The Effects of In Utero Exposure to Influenza on Birth and Infant Outcomes in the US. POPULATION AND DEVELOPMENT REVIEW 2019; 45:489-523. [PMID: 31582859 PMCID: PMC6767066 DOI: 10.1111/padr.12232] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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Rolfes MA, Vonglokham P, Khanthamaly V, Chitry B, Pholsena V, Chitranondh V, Mirza SA, Moen A, Bresee JS, Xeuatvongsa A, Olsen SJ. Measurement of birth outcomes in analyses of the impact of maternal influenza vaccination. Influenza Other Respir Viruses 2019; 13:547-555. [PMID: 31424627 PMCID: PMC6800304 DOI: 10.1111/irv.12673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/19/2019] [Accepted: 07/23/2019] [Indexed: 11/29/2022] Open
Abstract
Background The estimated association of maternal influenza vaccination and birth outcomes may be sensitive to methods used to define preterm birth or small‐for‐gestational age (SGA). Methods In a cohort of pregnant women in Lao People's Democratic Republic, we estimated gestational age from: (a) date of last menstrual period (LMP), (b) any prenatal ultrasound, (c) first trimester ultrasound, (d) Ballard Score at delivery, and (e) an algorithm combining LMP and ultrasound. Infants were classified as SGA at birth using a Canadian, global, and equation‐based growth reference. We estimated the association of maternal influenza vaccination and birth outcomes, by influenza activity, using multivariable log‐binomial regression and Cox proportional hazards regression with vaccination as a time‐varying exposure. Results The frequency of preterm birth in the cohort varied by method to estimate gestational age, from 5% using Ballard Score to 15% using any ultrasound. Using LMP, any ultrasound, or the algorithm, we found statistically significant reductions in preterm birth among vaccinated women during periods of high influenza activity and statistically significant increases in SGA, using a Canadian growth reference. We did not find statistically significant associations with SGA when using global or equation‐based growth references. Conclusions The association of maternal influenza vaccination and birth outcomes was most affected by the choice of a growth reference used to define SGA at birth. The association with pre‐term birth was present and consistent across multiple statistical approaches. Future studies of birth outcomes, specifically SGA, should carefully consider the potential for bias introduced by measurement choice.
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Affiliation(s)
- Melissa A Rolfes
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Viengphone Khanthamaly
- Influenza Program, U.S. CDC-Lao PDR, American Embassy, Vientiane, Lao People's Democratic Republic
| | - Bounlap Chitry
- Mother and Child Hospital, Vientiane, Lao People's Democratic Republic
| | | | - Visith Chitranondh
- Luang Prabang Provincial Hospital, Luang Prabang, Lao People's Democratic Republic
| | - Sara A Mirza
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Ann Moen
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Joseph S Bresee
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Sonja J Olsen
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
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7
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Trushakova S, Kisteneva L, Guglieri-López B, Mukasheva E, Kruzhkova I, Mira-Iglesias A, Krasnoslobodtsev K, Morozova E, Kolobukhina L, Puig-Barberà J, Burtseva E. Epidemiology of influenza in pregnant women hospitalized with respiratory illness in Moscow, 2012/2013-2015/2016: a hospital-based active surveillance study. BMC Pregnancy Childbirth 2019; 19:72. [PMID: 30770729 PMCID: PMC6377748 DOI: 10.1186/s12884-019-2192-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 01/15/2019] [Indexed: 12/18/2022] Open
Abstract
Background To better understand the impact of seasonal influenza in pregnant women we analyzed data collected during four seasons at a hospital for acute respiratory infection that specializes in treating pregnant women. Methods This was a single-center active surveillance study of women 15–44 years of age hospitalized for acute respiratory diseases between 2012/2013 and 2015/2016 in Moscow, Russian Federation. Women had to have been hospitalized within 7 days of the onset of symptoms. Swabs were taken within 48 h of admission, and influenza was detected by reverse transcription-polymerase chain reaction. Results During the four seasons, of the 1992 hospitalized women 1748 were pregnant. Laboratory-confirmed influenza was detected more frequently in pregnant women (825/1748; 47.2%) than non-pregnant women (58/244; 23.8%) (OR for influenza = 2.87 [95% CI, 2.10–3.92]; p < 0.001). This pattern was homogenous across seasons (p = 0.112 by test of homogeneity of equal odds). Influenza A(H1N1)pdm09 was the dominant strain in 2012/2013, A(H3N2) in 2013/2014, B/Yamagata lineage and A(H3N2) in 2014/2015, and A(H1N1)pdm09 in 2015/2016. Influenza-positive pregnant admissions went to the hospital sooner than influenza-negative pregnant admissions (p < 0.001). The risk of influenza increased by 2% with each year of age and was higher in women with underlying conditions (OR = 1.52 [95% CI, 1.16 to 1.99]). Pregnant women positive for influenza were homogeneously distributed by trimester (p = 0.37 for homogeneity; p = 0.49 for trend). Frequencies of stillbirth, delivery, preterm delivery, and caesarean delivery did not significantly differ between influenza-positive and influenza-negative hospitalized pregnant women or between subtypes/lineages. Conclusions Pregnant women are at increased risk for hospitalization due to influenza irrespective of season, circulating viruses, or trimester. Electronic supplementary material The online version of this article (10.1186/s12884-019-2192-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Svetlana Trushakova
- Ministry of Health of the Russian Federation, FSBI "N.F. Gamaleya NRCEM", 16, Gamaleya str, Moscow, Russia Moscow, 123098, Russian Federation.
| | - Lidiya Kisteneva
- Ministry of Health of the Russian Federation, FSBI "N.F. Gamaleya NRCEM", 16, Gamaleya str, Moscow, Russia Moscow, 123098, Russian Federation
| | - Beatriz Guglieri-López
- Fundación para el Fomento de la Investigación Sanitaria y Biomédica (FISABIO) de la Comunidad Valenciana, Avda Catalunya 21, 46020, Valencia, Spain
| | - Evgenia Mukasheva
- Ministry of Health of the Russian Federation, FSBI "N.F. Gamaleya NRCEM", 16, Gamaleya str, Moscow, Russia Moscow, 123098, Russian Federation
| | - Irina Kruzhkova
- Ministry of Health of the Russian Federation, FSBI "N.F. Gamaleya NRCEM", 16, Gamaleya str, Moscow, Russia Moscow, 123098, Russian Federation
| | - Ainara Mira-Iglesias
- Fundación para el Fomento de la Investigación Sanitaria y Biomédica (FISABIO) de la Comunidad Valenciana, Avda Catalunya 21, 46020, Valencia, Spain
| | - Kirill Krasnoslobodtsev
- Fundación para el Fomento de la Investigación Sanitaria y Biomédica (FISABIO) de la Comunidad Valenciana, Avda Catalunya 21, 46020, Valencia, Spain
| | - Ekaterina Morozova
- Fundación para el Fomento de la Investigación Sanitaria y Biomédica (FISABIO) de la Comunidad Valenciana, Avda Catalunya 21, 46020, Valencia, Spain
| | - Ludmila Kolobukhina
- Ministry of Health of the Russian Federation, FSBI "N.F. Gamaleya NRCEM", 16, Gamaleya str, Moscow, Russia Moscow, 123098, Russian Federation
| | - Joan Puig-Barberà
- Fundación para el Fomento de la Investigación Sanitaria y Biomédica (FISABIO) de la Comunidad Valenciana, Avda Catalunya 21, 46020, Valencia, Spain
| | - Elena Burtseva
- Ministry of Health of the Russian Federation, FSBI "N.F. Gamaleya NRCEM", 16, Gamaleya str, Moscow, Russia Moscow, 123098, Russian Federation
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Rasmussen IS, Mortensen LH, Krause TG, Nybo Andersen AM. The association between seasonal influenza-like illness cases and foetal death: a time series analysis. Epidemiol Infect 2018; 147:e61. [PMID: 30501687 PMCID: PMC6518601 DOI: 10.1017/s0950268818003254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 10/09/2018] [Accepted: 11/05/2018] [Indexed: 11/07/2022] Open
Abstract
It has been reported that foetal death follows a seasonal pattern. Influenza virus infection has been postulated as one possible contributor to this seasonal variation. This ecological study explored the temporal association between the influenza activity and the frequency of foetal death. Time series analysis was conducted using weekly influenza-like illness consultation proportions from the Danish sentinel surveillance system and weekly proportions of spontaneous abortions and stillbirths from hospital registers from 1994 to 2009. The association was examined in an autoregressive (AR) integrated (I) moving average (MA) model and subsequently analysed with cross-correlation functions. Our findings confirmed the well-known seasonality in influenza, but also seasonality in spontaneous abortion. No clear pattern of seasonality was found for stillbirths, although the analysis exposed dependency between observations. One final AR integrated MA model was identified for the influenza-like illness (ILI) series. We found no statistically significant relationship between weekly influenza-like illness consultation proportions and weekly spontaneous abortion proportions (five lags: P = 0.52; 11 lags: P = 0.91) or weekly stillbirths (five lags: P = 0.93; 11 lags: P = 0.40). Exposure to circulating influenza during pregnancy was not associated with rates of spontaneous abortions or stillbirths. Seasonal variations in spontaneous abortion were confirmed and this phenomenon needs further investigation.
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Affiliation(s)
- I. S. Rasmussen
- Section of Epidemiology, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Microbiology, Herlev and Gentofte Hospital, University of Copenhagen, Herlev, Denmark
| | - L. H. Mortensen
- Section of Epidemiology, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
- Methods and Analysis, Statistics Denmark, Copenhagen, Denmark
| | - T. G. Krause
- Department of Infectious Disease Epidemiology and Prevention, Statens Serum Institut, Copenhagen, Denmark
| | - A-M. Nybo Andersen
- Section of Epidemiology, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
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Liu WY, Yu ZB, Qiu HY, Wang JB, Chen XY, Chen K. Association between ambient air pollutants and preterm birth in Ningbo, China: a time-series study. BMC Pediatr 2018; 18:305. [PMID: 30236089 PMCID: PMC6147039 DOI: 10.1186/s12887-018-1282-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 09/12/2018] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Exposure to air pollutants has been related to preterm birth, but little evidence can be available for PM2.5, O3 and CO in China. This study aimed to investigate the short-term effect of exposure to air pollutants on risk preterm birth during 2014-2016 in Ningbo, China. METHODS We conducted a time-series study to evaluate the associations between daily preterm birth and major air pollutants (including PM2.5, PM10, SO2, NO2, O3 and CO) in Ningbo during 2014-2016. A General Additive Model extend Poisson regression was used to evaluate the relationship between preterm birth and air pollution with adjustment for time-trend, meteorological factors and day of the week (DOW). We also conducted a subgroup analysis by season and age. RESULTS In this study, a total of 37,389 birth occurred between 2014 and 2016 from the Electronic Medical Records System of Ningbo Women and Children's Hospital, of which 5428 were verified as preterm birth. The single pollutant model suggested that lag effect of PM2.5, PM10, NO2 reached a peak at day 3 before delivery and day 6 for SO2, and no relationships were observed for O3 and preterm birth. Excess risks (95% confidence intervals) for an increase of IQR of air pollutant concentrations were 4.84 (95% CI: 1.77, 8.00) for PM2.5, 3.56 (95% CI: 0.07, 7.17) for PM10, 3.65 (95% CI: 0.86, 6.51) for SO2, 6.49 (95% CI: 1.86, 11.34) for NO2, - 0.90 (95% CI: -4.76, 3.11) for O3, and 3.36 (95% CI: 0.50, 6.30) for CO. Sensitivity analyses by exclusion of maternal age < 18 or > 35 years did not materially alter our results. CONCLUSIONS This study indicates that short-term exposure to air pollutants (including PM2.5, PM10, SO2, NO2) are positively associated with risk of preterm birth in Ningbo, China.
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Affiliation(s)
- Wen-Yuan Liu
- Key laboratory of maternal-fetal medicine, Ningbo Women and Children’s Hospital, Ningbo, 315012 China
| | - Zhe-Bin Yu
- Department of Epidemiology and Biostatistics, School of Public Health, Zhejiang University, Hangzhou, 310058 China
- Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058 China
| | - Hai-Yan Qiu
- Key laboratory of maternal-fetal medicine, Ningbo Women and Children’s Hospital, Ningbo, 315012 China
| | - Jian-Bing Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Zhejiang University, Hangzhou, 310058 China
- Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058 China
| | - Xue-Yu Chen
- Department of Epidemiology and Biostatistics, School of Public Health, Zhejiang University, Hangzhou, 310058 China
| | - Kun Chen
- Department of Epidemiology and Biostatistics, School of Public Health, Zhejiang University, Hangzhou, 310058 China
- Research Center for Air Pollution and Health, Zhejiang University, Hangzhou, 310058 China
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The Relationship Between 2009 Pandemic H1N1 Influenza During Pregnancy and Preterm Birth: A Population-based Cohort Study. Epidemiology 2018; 29:107-116. [PMID: 28930786 DOI: 10.1097/ede.0000000000000753] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Previous studies of maternal influenza illness and preterm birth have yielded inconsistent results. Our objective was to assess the association between 2009 pandemic H1N1 (pH1N1) influenza during pregnancy and preterm birth in a large obstetrical population. METHODS We linked a province-wide birth registry with health administrative databases to identify influenza-coded hospitalizations, emergency department visits, or physician visits among pregnant women during the 2009 H1N1 pandemic (our proxy for clinical pH1N1 influenza illness). Using Cox regression, we estimated adjusted hazard ratios (aHR) for preterm birth and spontaneous preterm birth treating influenza as a time-varying exposure. RESULTS Among 192,082 women with a singleton live birth, 2,925 (1.5%) had an influenza-coded health care encounter during the 2009 H1N1 pandemic. Compared with unexposed pregnancy time, there was no association between exposure to the pandemic, with or without clinical influenza illness, and preterm birth (no pH1N1 diagnosis: aHR = 1.0; 95% confidence interval [CI] = 0.98, 1.1; pH1N1 diagnosis: aHR = 1.0; 95% CI = 0.88, 1.2). Among women with preexisting medical conditions, influenza was associated with increased preterm birth (aHR = 1.5; 95% CI = 1.1, 2.2) and spontaneous preterm birth (aHR = 1.7; 95% CI = 1.1, 2.6), and these associations were strongest in the third trimester and when data were analyzed to allow for a transient acute effect of influenza. CONCLUSIONS In the general obstetrical population, there was no association between pH1N1 influenza illness and preterm birth, but women with preexisting medical conditions known to increase the risk of influenza-associated morbidity were at elevated risk.
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Hutcheon JA, Savitz DA. Invited Commentary: Influenza, Influenza Immunization, and Pregnancy-It's About Time. Am J Epidemiol 2016; 184:187-91. [PMID: 27449413 DOI: 10.1093/aje/kww042] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 03/31/2016] [Indexed: 11/14/2022] Open
Abstract
Immunization of pregnant women against influenza has the potential to reduce adverse fetal outcomes by reducing prenatal exposure to influenza illness. However, as touched on by Fell et al. (Am J Epidemiol. 2016;184(3):163-175) and Vazquez-Benitez et al. (Am J Epidemiol. 2016;184(3):176-186) in this issue of the Journal, observational studies in which the causal effect of maternal influenza illness and influenza immunization on fetal health are evaluated are prone to bias because of the complex temporal nature of influenza illness seasonality, influenza immunization schedules, and gestation itself. Immortal time bias is introduced by an "anytime-in-pregnancy" exposure definition because the shortened pregnancy duration associated with many adverse fetal outcomes limits the opportunity to become exposed, whereas including follow-up time during which pregnancies are no longer at risk of an adverse outcome (e.g., gestational time after 37 weeks in studies of preterm birth) can lead to overestimation of any true benefits of immunization (or harms from influenza illness). We present a framework to avoid time-related biases in the study of influenza illness and immunization in pregnancy and advise that investigations of fetal benefit from maternal influenza immunization should only be undertaken when information is available on the calendar time of influenza virus circulation and the gestational age at which maternal influenza immunization occurred.
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