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The impact of perinatal maternal stress on the maternal and infant gut and human milk microbiomes: A scoping review protocol

  • Niamh Ryan ,

    Roles Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Project administration, Validation, Visualization, Writing – original draft, Writing – review & editing

    122117697@umail.ucc.ie

    Affiliation School of Nursing and Midwifery, University College Cork, Wilton, Cork, Ireland

  • Patricia Leahy-Warren,

    Roles Conceptualization, Data curation, Formal analysis, Methodology, Supervision, Validation, Visualization, Writing – review & editing

    Affiliation School of Nursing and Midwifery, University College Cork, Wilton, Cork, Ireland

  • Helen Mulcahy,

    Roles Conceptualization, Methodology, Project administration, Supervision, Validation, Visualization, Writing – review & editing

    Affiliation School of Nursing and Midwifery, University College Cork, Wilton, Cork, Ireland

  • Siobhain O’Mahony,

    Roles Conceptualization, Data curation, Formal analysis, Methodology, Supervision, Validation, Visualization, Writing – review & editing

    Affiliation Department of Anatomy and Neuroscience, APC Microbiome Ireland, University College Cork, Ireland

  • Lloyd Philpott

    Roles Conceptualization, Data curation, Formal analysis, Methodology, Supervision, Validation, Visualization, Writing – review & editing

    Affiliation School of Nursing and Midwifery, University College Cork, Wilton, Cork, Ireland

Abstract

Objective

The objective of this scoping review is to review the research evidence regarding the impact of perinatal maternal stress on the maternal and infant gut and human milk microbiomes.

Introduction

Perinatal stress which refers to psychological stress experienced by individuals during pregnancy and the postpartum period is emerging as a public health concern. Early exposure of infants to perinatal maternal stress can potentially lead to metabolic, immune, and neurobehavioral disorders that extend into adulthood. The role of the gut and human milk microbiome in the microbiome-gut-brain axis as a mechanism of stress transfer has been previously reported. A transfer of colonised aberrant microbiota from mother to infant is proposed to predispose the infant to a pro- inflammatory microbiome with dysregulated metabolic process thereby initiating early risk of chronic diseases. The interplay of perinatal maternal stress and its relationship to the maternal and infant gut and human milk microbiome requires further systematic examination in the literature.

Inclusion criteria

This scoping review is an exploratory mapping review which will focus on the population of mothers and infants with the exploration of the key concepts of maternal stress and its impact on the maternal and infant gut and human milk microbiome in the context of the perinatal period. It will focus on the pregnancy and the post-natal period up to 6 months with infants who are exclusively breastfed.

Methods

This study will be guided by the Joanna Briggs Institute’s (JBI) methodology for scoping reviews along with use of the Prisma Scr reporting guideline. A comprehensive search will be conducted using the following databases, CINAHL Complete; MEDLINE; PsycINFO, Web of Science and Scopus. A search strategy with pre-defined inclusion and exclusion criteria will be used to retrieve peer reviewed data published in English from 2014 to present. Screening will involve a three-step process with screening tool checklists. Results will be presented in tabular and narrative summaries, covering thematic concepts and their relationships. This protocol is registered with Open Science Framework DOI 10.17605/OSF.IO/5SRMV.

Introduction

Maternal mental health in the perinatal period refers to the psychological well-being of women during pregnancy and the postnatal period [1]. It includes conditions such as depression, anxiety, and stress. Perinatal maternal stress in particular is a public health concern as studies worldwide are reporting a rising prevalence of between 5% - 93% [25]. Its rise reportedly influenced by societal pressures, social isolation, economic challenges, pregnancy, and birthing complications [6, 7].

Maternal mental health not only impacts the health of the mother, but it can also have long lasting implications for infant and child development [812]. In the past 30 years, a substantial body of evidence is building on Barker’s theory of the developmental origin of health and disease (DoHD) which demonstrated that adverse maternal conditions, such as stress during the first 1000 days of life can increase the risk of metabolic, immunologic, and neurobehavioral disorders in offspring [1322]. Given that perinatal maternal stress is a prevalent and modifiable factor that affects maternal, foetal and child health it requires focused attention in research and preventative health care.

There is growing researcher interest in how stress transfers from the mother to the infant and the role that the gut microbiome plays in the process [23, 24]. The gut microbiome, composed of trillions of microorganisms in the digestive tract, influences gut, immune and metabolic health [25, 26]. The balance of the gut microbiome is crucial for overall well-being, with disruptions linked to various health problems such as cardiometabolic diseases, digestive disorders, neurological disorders [25, 2733]. There is now evidence that both the gut and human milk microbiome is altered by many maternal factors such as maternal health, maternal body mass index, mode of delivery, and antibiotic use [3438]. This alteration or dysbiosis in the microbiome caused by aberrant microbiota is proposed to be transferred to the infant, predisposing them to a pro-inflammatory microbiome with dysregulated metabolic processes leading to adverse health conditions. Focusing on the influence of maternal stress, this review is interested in the brain gut axis (the two-way communication between the central nervous system and the gut microbiome and its impact on altering maternal and infant gut and human milk microbiomes. Limited research has focused on how maternal perinatal stress as a single variable affects the microbiomes, with no comprehensive review of existing evidence. Therefore, conducting a scoping review is timely and warranted to systematically map this research area. Seminal work by Arksey and O’Malley describes a scoping review as beneficial for examining the extent, range, and nature of research, while also identifying gaps in the evidence base [39]. This review also highlights the importance of perinatal stress for maternal and infant well-being. It emphasizes the necessity for clinician intervention and highlights research gaps. By tackling perinatal stress, immediate risks such as low birth weight and preterm delivery could be reduced, while also fostering stronger mother-child bonding [4042]. Furthermore, addressing maternal stress may mitigate negative behaviours like smoking and alcohol consumption thus further improving lifestyle [43, 44].Given the relative novelty of data in this topic, understanding the depth of evidence through mapping is crucial, as feasibility of a systematic review may be difficult due to a potential lack of research [45]. It is advised that a protocol is essential prior to a scoping review [46].

Review question

The review question was formulated using the Participant (P), Concept (C), Context (C) framework following JBI guidance [47] (Table 1). The review aims to provide an overview of the evidence to address the following question: What is the impact of perinatal maternal stress on the maternal and infant gut and human milk microbiomes? With the objective to; a) Identify the methods and tools used by researchers to measure stress and the microbiome(s), b) Identity if perinatal maternal stress has an impact on bacterial taxa in the microbiome(s), c) Identify if perinatal maternal stress has an impact on bacterial diversity of the microbiome(s).

Methods

The scoping review will be conducted following the guidelines for scoping reviews described by the JBI Manual for Evidence Synthesis and Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping review (PRISMA-ScR) [46, 47].

Study eligibility criteria

The inclusion exclusion criteria for this review will be based on the population-concept-context framework. (Fig 1) (Table 1) recommended by the Johanna Briggs Institute (JBI) [47].

Agreement among five researchers regarding inclusion and exclusion criteria at the start of the review process occurred, with each researcher agreeing with the final criteria. The eligibility criteria for this study are outlined in Table 2 where it is matched to population concepts and context.

Types of sources

This review will include primary peer reviewed papers that explored maternal stress, the human milk microbiome, and maternal and infant gut microbiome. Secondary analyses, such as systematic reviews will be included if they meet the inclusion criteria. Case reports, book chapters, guidelines, commentaries, editorials, letters to editors, and narrative reviews are excluded as these sources do not directly address the review question and pose challenges in data extraction. This review will not include grey literature due to the difficulty in retrieving and extracting the data, but also in evaluating its credibility due to the absence of standardized quality indicators or peer review processes [53]. The below Table 3 identifies final eligibility criteria for types and sources of evidence to be included in the protocol and full review.

Search strategy

The review will follow the three-step JBI process: To begin initial searches will be conducted in PubMed and CINAHL to identify relevant papers. Secondly text words, keywords, and index terms will be analysed from identified articles to develop a comprehensive search strategy for all databases (See S1 File). Finally, reference lists of identified articles will be searched for additional studies. Keywords and search terms will be peer-reviewed using PRESS guidance with a librarian. To ensure comprehensive results, there will be multiple searches, one for each concept (See S1 Table). All searches will use Boolean operators AND and OR in title (TI) and abstract searches (AB) with CINAHL Headings and Mesh headings used as appropriate. Information will be sourced from the following databases CINAHL Complete, Psych Info, PubMed, Web of Science and Scopus. The review will restrict analysis to English articles, however initial searches will include all languages to determine the number if any in other languages to avoid bias.

Source of evidence selection

Following the search, all included studies will be exported to Covidence, and all duplicates removed. Two reviewers (NR HM LP SOM PLW) will independently screen all papers in 2 stages: title and abstract screening, and full-text screening. Agreement from two reviewers will be required for an article to be excluded at the title-screening stage. The full text of selected papers will be assessed against the inclusion criteria by two reviewers. Reasons for exclusion of sources of evidence at full text that do not meet the inclusion criteria will be recorded and reported in the scoping review. Any conflicts in the screening stage will be resolved through the inclusion of a third reviewer. The results of the search will be presented in a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram [54] (Fig 2).

thumbnail
Fig 2. Prisma flow diagram.

*Consider, if feasible to do so, reporting the number of records identified from each database or register searched (rather than the total number across all databases/registers). **If automation tools were used, indicate how many records were excluded by a human and how many were excluded by automation tools. From: Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71. doi: 10.1136/bmj.n71. For more information, visit: http://www.prisma-statement.org/.

https://doi.org/10.1371/journal.pone.0304787.g002

Data extraction

Data will be extracted from papers included in the scoping review by two reviewers using a data extraction tool developed by the reviewer NR on Covidence (S2 File). Data extracted will include author’s name, year, and type of publication. The aims/purpose in relation to the concepts and objectives will be extracted along with methodology and methods, sample (e.g. maternal/ infant or both). Analysis of confounding variables will be noted along with statistical tests and key findings that relate to the scoping review question with limitations/quality issues noted. The extraction table will be piloted on two papers to ensure all relevant results are extracted and to improve transparency and consistency [39, 46].

Data analysis and presentation

The results will be presented in a narrative summary, along with tables and charts. Gaps in the evidence will be identified at this stage. Preferred Reporting Items for Systematic Reviews and Meta-analyses extension for Scoping review (PRISMA-ScR) will be completed along with presentation of results to ensure each element is covered within the scoping review (S3 File).

Supporting information

S2 File. Data extraction template for covidence.

https://doi.org/10.1371/journal.pone.0304787.s002

(DOCX)

Acknowledgments

This scoping review was produced by author Niamh Ryan NR as a contribution to her Doctoral degree.

References

  1. 1. World Health Organisation (WHO). 2021. [cited 2024 Mar 12]. Maternal health: fact sheet on Sustainable Development Goals (‎SDGs)‎: health targets. Available from: https://www.who.int/europe/publications/i/item/WHO-EURO-2017-2363-42118-58039.
  2. 2. Woods SM, Melville JL, Guo Y, Fan MY, Gavin A. Psychosocial stress during pregnancy. Am J Obstet Gynecol. 2010 Jan;202(1):61.e1–61.e7. pmid:19766975
  3. 3. Vijayaselvi DrR. Risk Factors for Stress During Antenatal Period Among Pregnant Women in Tertiary Care Hospital of Southern India. JOURNAL OF CLINICAL AND DIAGNOSTIC RESEARCH. 2015; pmid:26557568
  4. 4. Pope J, Olander EK, Leitao S, Meaney S, Matvienko-Sikar K. Prenatal stress, health, and health behaviours during the COVID-19 pandemic: An international survey. Women and Birth. 2022 May;35(3):272–9. pmid:33757750
  5. 5. Hannon S, Gartland D, Higgins A, Brown SJ, Carroll M, Begley C, et al. Maternal mental health in the first year postpartum in a large Irish population cohort: the MAMMI study. Arch Womens Ment Health. 2022 Jun 29;25(3):641–53. pmid:35488067
  6. 6. Gao Y, Tang X, Deng R, Liu J, Zhong X. Latent Trajectories and Risk Factors of Prenatal Stress, Anxiety, and Depression in Southwestern China—A Longitudinal Study. Int J Environ Res Public Health. 2023 Feb 21;20(5):3818. pmid:36900833
  7. 7. Kingston D, Tough S, Whitfield H. Prenatal and Postpartum Maternal Psychological Distress and Infant Development: A Systematic Review. Child Psychiatry Hum Dev. 2012 Oct 10;43(5):683–714. pmid:22407278
  8. 8. Kingston D, Tough S. Prenatal and Postnatal Maternal Mental Health and School-Age Child Development: A Systematic Review. Matern Child Health J. 2014 Sep 19;18(7):1728–41. pmid:24352625
  9. 9. Fransson E. Psychoneuroimmunology in the context of perinatal depression—Tools for improved clinical practice. Brain Behav Immun Health. 2021;17. pmid:34589817
  10. 10. Surkan PJ, Kennedy CE, Hurley KM, Black MM. Maternal depression and early childhood growth in developing countries: systematic review and meta-analysis. Bull World Health Organ. 2011 Aug 1;89(8):608–615E. pmid:21836759
  11. 11. Grigoriadis S, Graves L, Peer M, Mamisashvili L, Tomlinson G, Vigod SN, et al. Maternal Anxiety During Pregnancy and the Association With Adverse Perinatal Outcomes. J Clin Psychiatry. 2018 Sep 4;79(5).
  12. 12. Field T. Postnatal anxiety prevalence, predictors and effects on development: A narrative review. Infant Behav Dev. 2018 May 1;51:24–32. pmid:29544195
  13. 13. Barker DJP. The origins of the developmental origins theory. J Intern Med. 2007 May 10;261(5):412–7. pmid:17444880
  14. 14. Tate EB, Wood W, Liao Y, Dunton GF. Do stressed mothers have heavier children? A meta-analysis on the relationship between maternal stress and child body mass index. Obesity Reviews. 2015 May 1;16(5):351–61. pmid:25879393
  15. 15. Glover VO’Donnell KJ, O’Connor TG, Fisher J. Prenatal maternal stress, fetal programming, and mechanisms underlying later psychopathology—A global perspective. Dev Psychopathol. 2018;30(3):843–54. pmid:30068411
  16. 16. Veru F, Laplante DP, Luheshi G, King S. Prenatal maternal stress exposure and immune function in the offspring. Stress. 2014;17(2):133–48. pmid:24417382
  17. 17. Dunton GF, Chu D, Naya CH, Belcher BR, Mason TB. Longitudinal associations of maternal stress and child stress with child body mass index trajectory. Pediatr Obes. 2021 Mar 1;16(3). pmid:32881324
  18. 18. Sun Y, Xie R, Li L, Jin G, Zhou B, Huang H, et al. Prenatal Maternal Stress Exacerbates Experimental Colitis of Offspring in Adulthood. Front Immunol. 2021;12. pmid:34804005
  19. 19. Walsh K, McCormack CA, Webster R, Pinto A, Lee S, Feng T, et al. Maternal prenatal stress phenotypes associate with fetal neurodevelopment and birth outcomes. Proceedings of the National Academy of Sciences. 2019 Nov 26;116(48):23996–4005. pmid:31611411
  20. 20. Marques AHO’Connor TG, Roth C, Susser E, Bjørke-Monsen AL. The influence of maternal prenatal and early childhood nutrition and maternal prenatal stress on offspring immune system development and neurodevelopmental disorders. Front Neurosci. 2013;(7 JUL). pmid:23914151
  21. 21. Flanigan C, Sheikh A, DunnGalvin A, Brew BK, Almqvist C, Nwaru BI. Prenatal maternal psychosocial stress and offspring’s asthma and allergic disease: A systematic review and meta‐analysis. Clinical & Experimental Allergy. 2018 Apr 8;48(4):403–14. pmid:29331049
  22. 22. Van den Bergh BRH, van den Heuvel MI, Lahti M, Braeken M, de Rooij SR, Entringer S, et al. Prenatal developmental origins of behavior and mental health: The influence of maternal stress in pregnancy. Neurosci Biobehav Rev. 2020;117:26–64. pmid:28757456
  23. 23. Galley JD, Mashburn-Warren L, Blalock LC, Lauber CL, Carroll JE, Ross KM, et al. Maternal anxiety, depression and stress affects offspring gut microbiome diversity and bifidobacterial abundances. Brain Behav Immun. 2023;107:253–64. pmid:36240906
  24. 24. Rotem-Kohavi N, Keane J, Clarke G, Dinan TG, Cryan JF, McCarthy FP, et al. The microbiome-gut-brain axis: A new window to view the impact of prenatal stress on early neurodevelopment. Prenatal Stress and Child Development. 2021. 165–191 p.
  25. 25. Moloney RD, Desbonnet L, Clarke G, Dinan TG, Cryan JF. The microbiome: Stress, health and disease. Mammalian Genome. 2014;25(1–2):49–74. pmid:24281320
  26. 26. Gohir W, Ratcliffe EM, Sloboda DM. Of the bugs that shape us: maternal obesity, the gut microbiome, and long-term disease risk. Pediatr Res [Internet]. 2015 Jan;77(1–1):196–204. Available from: https://ucc.idm.oclc.org/login?URL=https://search.ebscohost.com/login.aspx?direct=true&db=rzh&AN=109704333&site=ehost-live. pmid:25314580
  27. 27. Hantsoo L, Zemel BS. Stress gets into the belly: Early life stress and the gut microbiome. Behavioural Brain Research. 2021 Sep;414:113474. pmid:34280457
  28. 28. Robertson RC, Manges AR, Finlay BB, Prendergast AJ. The Human Microbiome and Child Growth–First 1000 Days and Beyond. Trends Microbiol. 2019 Feb 1;27(2):131–47. pmid:30529020
  29. 29. Mafra D, Lobo JC, Barros AF, Koppe L, Vaziri ND, Fouque D. Role of altered intestinal microbiota in systemic inflammation and cardiovascular disease in chronic kidney disease. Future Microbiol. 2014;9(3):399–410. pmid:24762311
  30. 30. Zafar H, Saier MH. Gut Bacteroides species in health and disease. Gut Microbes. 2021 Jan 1;13(1).
  31. 31. Zheng D, Liwinski T, Elinav E. Interaction between microbiota and immunity in health and disease. Cell Res. 2020 Jun 20;30(6):492–506. pmid:32433595
  32. 32. Codagnone MG, Spichak S, O’Mahony SM, O’Leary OF, Clarke G, Stanton C, et al. Programming Bugs: Microbiota and the Developmental Origins of Brain Health and Disease. Biol Psychiatry. 2019;85(2):150–63. pmid:30064690
  33. 33. Mohammadkhah AI, Simpson EB, Patterson SG, Ferguson JF. Development of the Gut Microbiome in Children, and Lifetime Implications for Obesity and Cardiometabolic Disease. Children. 2018 Nov 27;5(12):160. pmid:30486462
  34. 34. Azad MB, Konya T, Maughan H, Guttman DS, Field CJ, Chari RS, et al. Gut microbiota of healthy Canadian infants: Profiles by mode of delivery and infant diet at 4 months. CMAJ Canadian Medical Association Journal. 2013 Mar 19;185(5):385–94. pmid:23401405
  35. 35. Forbes JD, Azad MB, Vehling L, Tun HM, Konya TB, Guttman DS, et al. Association of Exposure to Formula in the Hospital and Subsequent Infant Feeding Practices With Gut Microbiota and Risk of Overweight in the First Year of Life. JAMA Pediatr [Internet]. 2018 Jul;172(7):e181161–1. Available from: https://ucc.idm.oclc.org/login?URL=https://search.ebscohost.com/login.aspx?direct=true&db=rzh&AN=130539050&site=ehost-live. pmid:29868719
  36. 36. Mantziari A, Rautava S. Factors influencing the microbial composition of human milk. Semin Perinatol. 2021 Dec;45(8):151507. pmid:34736762
  37. 37. Lemas DJ, Yee S, Cacho N, Miller D, Cardel M, Gurka M, et al. Exploring the contribution of maternal antibiotics and breastfeeding to development of the infant microbiome and pediatric obesity. Semin Fetal Neonatal Med [Internet]. 2016 Dec;21(6):406–9. Available from: https://ucc.idm.oclc.org/login?URL=https://search.ebscohost.com/login.aspx?direct=true&db=rzh&AN=119482057&site=ehost-live. pmid:27424917
  38. 38. de Koff EM, van Baarle D, van Houten MA, Reyman M, Berbers GAM, van den Ham F, et al. Mode of delivery modulates the intestinal microbiota and impacts the response to vaccination. Nat Commun [Internet]. 2022 Nov 15;13(1):6638. Available from: https://www.nature.com/articles/s41467-022-34155-2. pmid:36380002
  39. 39. Arksey HO’Malley L. Scoping studies: Towards a methodological framework. International Journal of Social Research Methodology: Theory and Practice. 2005 Feb;8(1):19–32.
  40. 40. Littleton HL, Bye K, Buck K, Amacker A. Psychosocial stress during pregnancy and perinatal outcomes: a meta-analytic review. Journal of Psychosomatic Obstetrics & Gynecology. 2010 Nov 2;31(4):219–28. pmid:21039328
  41. 41. Van den Bergh BRH, Mulder EJH, Mennes M, Glover V. Antenatal maternal anxiety and stress and the neurobehavioural development of the fetus and child: links and possible mechanisms. A review. Neurosci Biobehav Rev. 2005 Apr;29(2):237–58.
  42. 42. McCarthy M, Houghton C, Matvienko-Sikar K. Women’s experiences and perceptions of anxiety and stress during the perinatal period: a systematic review and qualitative evidence synthesis. BMC Pregnancy Childbirth. 2021 Dec 6;21(1):811. pmid:34865642
  43. 43. Westerneng M, Witteveen AB, Warmelink JC, Spelten E, Honig A, de Cock P. Pregnancy-specific anxiety and its association with background characteristics and health-related behaviors in a low-risk population. Compr Psychiatry. 2017 May;75:6–13. pmid:28279817
  44. 44. Matvienko-Sikar K, Flannery C, Redsell S, Hayes C, Kearney PM, Huizink A. Effects of interventions for women and their partners to reduce or prevent stress and anxiety: A systematic review. Women and Birth. 2021 Mar;34(2):e97–117. pmid:32107141
  45. 45. Munn Z, Peters MDJ, Stern C, Tufanaru C, McArthur A, Aromataris E. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Med Res Methodol. 2018 Nov 19;18(1).
  46. 46. Peters MDJ, Godfrey C, McInerney P, Khalil H, Larsen P, Marnie C, et al. Best practice guidance and reporting items for the development of scoping review protocols. JBI Evid Synth. 2022 Apr 9;20(4):953–68. pmid:35102103
  47. 47. Peters MDJ, Marnie C, Tricco AC, Pollock D, Munn Z, Alexander L, et al. Updated methodological guidance for the conduct of scoping reviews. JBI Evid Synth. 2020 Oct;18(10):2119–26. pmid:33038124
  48. 48. Redpath N, Rackers HS, Kimmel MC. The Relationship Between Perinatal Mental Health and Stress: a Review of the Microbiome. Curr Psychiatry Rep. 2019;21(3).
  49. 49. Hantsoo L, Zemel BS. Stress gets into the belly: Early life stress and the gut microbiome. Behavioural Brain Research. 2021 Sep;414:113474. pmid:34280457
  50. 50. Linnér A, Almgren M. Epigenetic programming—The important first 1000 days. Acta Paediatrica, International Journal of Paediatrics. 2020;109(3):443–52.
  51. 51. Robertson RC, Manges AR, Finlay BB, Prendergast AJ. The Human Microbiome and Child Growth–First 1000 Days and Beyond. Trends Microbiol. 2019 Feb;27(2):131–47. pmid:30529020
  52. 52. Hu J, Aris IM, Lin PID, Rifas-Shiman SL, Perng W, Woo Baidal JA, et al. Longitudinal associations of modifiable risk factors in the first 1000 days with weight status and metabolic risk in early adolescence. American Journal of Clinical Nutrition. 2021 Jan 1;113(1):113–22. pmid:33184628
  53. 53. Adams RJ, Smart P, Huff AS. Shades of Grey: Guidelines for Working with the Grey Literature in Systematic Reviews for Management and Organizational Studies. International Journal of Management Reviews. 2017 Oct;19(4):432–54.
  54. 54. Tricco AC, Lillie E, Zarin W, O’Brien KK, Colquhoun H, Levac D, et al. PRISMA Extension for Scoping Reviews (PRISMA-ScR): Checklist and Explanation. Ann Intern Med. 2018 Oct 2;169(7):467–73. pmid:30178033