Evidence-based Medicine in Obstetrics and Gynaecology

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Evidence‐based Medicine in Obstetrics and Gynaecology


Siladitya Bhattacharya1 and Arri Coomarasamy2


1 School of Medicine and Dentistry, University of Aberdeen, Aberdeen, UK


2 Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK


Clinical care constantly challenges health professionals to ensure that techniques for diagnosis, prognosis and treatment are up to date and consistent with best practice. Given the exponential rise in the numbers of scientific publications, doctors increasingly face the double challenge of keeping up with the latest information and choosing the best tests or treatments based on sound evidence from appropriately conducted research.


One way of doing this successfully is to practice evidence‐based medicine (EBM). EBM is the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients [1]. It involves integrating clinical experience and skill with the best available external clinical evidence and awareness of an individual patient’s situation and preferences in making clinical decisions about their care.


In this chapter we explore all three components and show that EBM is not the preserve of non‐clinical researchers but that it is feasible to incorporate EBM within everyday practice by busy clinicians who devote their scarce reading time to selective, efficient, patient‐driven searching, appraisal and incorporation of the best available evidence. Clinical decisions should be integrated with individual clinical expertise in deciding whether and how it matches the patient’s clinical state, predicament and preferences, and thus whether it should be applied. Evidence‐based guidelines, however, cannot compensate for poor clinical skills in eliciting a diagnosis or interpreting a test result or performing a procedure.


Practical evidence‐based medicine


Any clinic consultation throws up a number of questions. For example, in a woman presenting with pelvic pain, what investigations are useful? If endometriosis is diagnosed, what is the best treatment which is consistent with the woman’s circumstances and preferences? Similarly, if no cause can be found what is the most effective way of dealing with the symptom of pain? The key principles underpinning the practice of EBM in this and other similar situations are captured in the five As: Ask, Acquire, Appraise, Apply and Audit.


Ask: framing a structured question


The first step in the practice of EBM is to transform an overarching clinical question, for example what is the best way to manage a particular case, into a series of focused answerable questions in a manner which facilitates a systematic enquiry. A standard approach is to use five components – population, intervention, comparison, outcome and design (PICOD) – to refine the question and enable a literature search to be carried out. Table 70.1 shows examples of how to frame similar questions. Although this approach may appear to be stilted, it merely disarticulates the steps of decision‐making which most clinicians accomplish intuitively and rapidly in everyday practice.


Table 70.1 Framing a structured question




























Component Question in Obstetrics Question in Gynaecology
Population Overweight or obese pregnant women Women with heavy menstrual bleeding
Intervention Antenatal intervention comprising exercise and/or diet Endometrial ablation
Comparator Usual antenatal care Levonorgestrel Intrauterine System
Outcome Large for gestational age baby ( wt > 90th centile) Improved quality of life
Design Randomised trial Randomised trial

Acquire: searching the literature


A structured detailed literature search can be cumbersome and time‐consuming, something that systematic reviewers and information scientists are well aware of. For busy clinicians there are significant advantages to a hierarchical approach to literature searches, starting with known repositories of clinical practice guidelines and evidence‐based reviews rather than primary research data (Fig. 70.1). However, it is important that the methods used by guidelines, systematic reviews and individual studies are robust and reflect the nature of the clinical questions. Guidelines and evidence summaries in obstetrics and gynaecology are regularly produced and updated by a number of organizations including professional bodies such as the Royal Colleges and professional societies as well as national organizations such as the National Institute of Health and Care Excellence (NICE) in the UK, and in some conditions by international bodies such as the World Health Organization (WHO).

Flow chart with boxes linked by arrows from guidelines and evidence summaries to systematic reviews and to primary research studies. Each has arrows pointing to appraise, adapt to local requirement and implement.

Figure 70.1 Searching the literature for evidence.


If high‐quality evidence‐based guidelines are unavailable, the next step is to search for good‐quality systematic reviews relevant to the questions at hand. If none is found, the next step is to seek primary research papers whose methodologies need to reflect the clinical question. For example, for effectiveness of interventions such as medical or surgical treatments or more complex interventions, the appropriate studies are randomized trials. Either cohort or case–control studies might be appropriate for investigating the aetiology of clinical conditions, while cohort studies are suitable for assessing prognosis. Test accuracy is often evaluated by cross‐sectional studies in which new tests are compared against a gold standard.


A list of some relevant sources of guidelines and evidence‐based summaries is shown in Table 70.2. The Cochrane Library and the Centre for Reviews and Dissemination (CRD) databases, including Database of Abstracts of Reviews of Effects (DARE), NHS Economic Evaluation Database (NHS EED) and Health Technology Assessment (HTA) Database), undertake high‐quality evidence synthesis exercises in a number of topics including obstetrics and gynaecology. In addition, publications databases such as Medline and PubMed are also sources of many systematic reviews. PubMed contains a systematic review filter called PubMed clinical queries, while Medline has the indexing time ‘reviews, systematic’ as a ‘publication type’. If no systematic reviews can be found, it is necessary to search for primary studies of relevance.


Table 70.2 Sources of some guidelines and evidence based summaries in obstetrics and gynaecology

















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Sep 7, 2020 | Posted by in GYNECOLOGY | Comments Off on Evidence-based Medicine in Obstetrics and Gynaecology

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Royal College of Obstetricians & Gynaecologists https://www.rcog.org.uk/guidelines
National Institute for Health and Care Excellence (NICE) https://www.nice.org.uk/guidance/published?
American College of Obstetricians and Gynaecologists http://www.acog.org/Resources‐And‐Publications
International Federation of Gynaecology and Obstetrics http://www.figo.org/publications‐resources
NHS National Library for Health