Background and purpose: Low back pain (LBP) is a common and costly problem during pregnancy and assumes to be a part of normal pregnancy caused by normal physiological changes. Pregnancy-related LBP is one of the main reasons for disability, absence from work and responsible for huge direct and indirect economical impact.  This article Systematically reviews papers concerning the epidemiology and risk factors on LBP in pregnant women.  Materials and methods: MEDLINE, CINAHL, Rose-Net, OVID, and BIDS were searched for the period of 1985-2003, using the key words 'low back pain', 'epidemiology', 'pregnancy', 'risk factors'. In addition, references given in relevant publications were used. Results: Eighteen studies were identified. Eleven studies investigated epidemiology of LBP during pregnancy and the prevalence were reported >50% in 8 (73%) studies.  Ten studies were carried out on the epidemiology of LBP after pregnancy.  The prevalence of LBP were reported >40% in 6 (60%) studies.  Among different reported risk factors, previous LBP as well as younger age were the most important risk factors. Conclusion: Although there were some methodological flaws (e.g., small sample size of the study population, lack of clear classification and definition for LBP, different study design, different methods of study implementation, etc.) which precludes strong conclusion, it appears that LBP is one of the most common problem, during pregnancy and after delivery. It should also be noted that education and certain exercises can be beneficial to the pregnant women in the absence of medical complications.

Background: Successful clinical decisions are the outcome of a complex process. In making them, we draw on information from scientific evidences, our personal experience and external rules and constraints. Considering that the explosive increase in the amount and quality of the scientific evidence that has come from both the laboratory bench and the bedside, we may lack the time, motivation, and basic skills needed to find, critically appraise, and synthesize information. Fortunately, Systematic reviews help us and answer sharply defined clinical questions. This article deals with two questions; a: what is a Systematic review and, b: how should we organize it? Methods: We searched MEDLINE database with search terms of Systematic review and narrative review, restricted to English language, without time limitation. Then we selected those articles written by renowned experts. Results: There are two types of review articles: narrative review and Systematic review. Narrative review has been the conventional method for writing review articles; since it is subjective, it may be subject to error and bias; in areas where there is lack or paucity of evidence, the narrative review may still be the best writing method. Systematic review is the precise, Systematic and classified method of reviewing the existing data and evidences. It is objective, constructive and comprehensive and has much less error and bias than the narrative review.Conclusion: Systematic reviews are thus a vital link in the great chain of evidence that stretches from the laboratory bench to the bedside. It is absolutely essential for targeting these goals, for writing a Systematic review, a fully trained team with an expert leader and a precise protocol is essential.

Background: In the outbreak of infectious diseases, non-pharmacological intervention might be the only available protection tools. The aim of this Systematic review is to investigate whether it is or is not necessary to wear masks in new corona virus (COVID-19) outbreaks in the community. Methods: On February, 28, 2020, related databases were searched with the following keywords: "COVID-19"; "COVID 19"; 2019-nCoV; 2019-CoV; coronavirus; mask* and facemask. We updated the search in March 13, 2020. A total of 982 relevant reports were identified after removing duplicates. Of these, 71 references were screened based on titles and abstracts. After excluding unrelated studies, 36 studies were included in the full-text review and were assessed for eligibility. Finally, 3 articles met our inclusion criteria. Results: In three wards of hospital with more exposure to infected patients, wearing the N95 respirator while using regular disinfectants and hand hygiene, was a better way to prevent COVID-19 transmission from patients to nurses and physicians when compared to non-users of masks. Another study on family members with a history of travelling to Wuhan, showed that those who had worn a surgical mask only during the hospital visit, were infected. However, the 7 years old child of the family who wore a surgical mask, was not found to be infected by COVID-19. Finally, none of eleven healthcare workers who had unprotected exposure with confirmed cases were infected. Conclusion: Due to the newness of the COVID-19 virus, no clinical trials have been found regarding the use of the masks in the prevention of the disease, and the level of evidence were low.

In recent years, published Systematic reviews in the world and in Iran have been increasing. These studies are an important resource to answer evidence‑, based clinical questions and assist health policy‑, makers and students who want to identify evidence gaps in published research. Systematic review studies, with or without meta‑, analysis, synthesize all available evidence from studies focused on the same research question. In this study, the steps for a Systematic review such as research question design and identification, the search for qualified published studies, the extraction and synthesis of information that pertain to the research question, and interpretation of the results are presented in details. This will be helpful to all interested researchers.

Conjunctivitis is a commonly encountered condition in ophthalmology clinics throughout the world. In the management of suspected cases of conjunctivitis, alarming signs for more serious intraocular conditions, such as severe pain, decreased vision, and painful pupillary reaction, must be considered. Additionally, a thorough medical and ophthalmic history should be obtained and a thorough physical examination should be done in patients with atypical findings and chronic course. Concurrent physical exam findings with relevant history may reveal the presence of a systemic condition with involvement of the conjunctiva. Viral conjunctivitis remains to be the most common overall cause of conjunctivitis. Bacterial conjunctivitis is encountered less frequently and it is the second most common cause of infectious conjunctivitis. Allergic conjunctivitis is encountered in nearly half of the population and the findings include itching, mucoid discharge, chemosis, and eyelid edema. Long-term usage of eye drops with preservatives in a patient with conjunctival irritation and discharge points to the toxic conjunctivitis as the underlying etiology. Effective management of conjunctivitis includes timely diagnosis, appropriate differentiation of the various etiologies, and appropriate treatment.

review articles are divided by two categories including narrative and Systematic reviews. Systematic review assesses related studies using a scientific planned method to answer a relevant research question.The overall structure of a Systematic review is comprised of seeking and finding related studies, apprising them according to clear criteria, combining the results and presenting them obviously and succinctly. This type of review helps decision makers to decide correctly regard to a topic which has been examined in various studies. Systematic review needs achieving experience and having enough time and the authors should have sufficient authority on the topic. Relatively identical processes have been suggested by different authors that usually include formulating the research question, setting the research protocol, literature search, extracting data, quality assessment, data analysis and presenting the data, and results interpretation. Performing these stages needs to consider the protocol or plan that usually has developed by the authors before beginning the study and following it may avoid any bios and deviation from the research line.The sections that are in a research article such as abstract, introduction, methods, results and discussion should also be considered in a Systematic review article.