Rapid qualitative review of ethical issues surrounding healthcare for pregnant women or women of reproductive age in epidemic outbreaks

How often is the placenta included in human pregnancy research? A rapid systematic review of the literature

Background: The placenta is a complex organ that plays a vital role not only in nutrient transfer but also in directing maternal and fetal physiological processes across pregnancy. Due to its multi-functionality, assessing the placenta can provide critical information about maternal and child health and risks of adverse outcomes. Objective: We aimed to quantify the percentage of human pregnancy studies that include placenta data. Methods: We conducted a rapid review of pregnancy studies conducted in the US that were published as original research in PubMed in 2018. Human studies conducted during the second trimester, third trimester, or labor and/or delivery were eligible. The systematic search produced 1,448 publications. After screening and full article review, 290 studies met all eligibility criteria. We then extracted data on study design, reporting of placenta data, time and type of data collection, and study objective categorization. Results: In total, 32% of studies were randomized controlled trials; the remaining were observational studies. Only 14% included placenta data of any kind. A total of 10% included placenta data during pregnancy and 7% included data after delivery; only 2% included both. Most data during pregnancy were collected by ultrasound and most data on the delivered placenta were from pathology exams. Study objectives were focused on maternal and/or infant outcomes (99.7%), while only one study had a placenta outcome. Conclusion: Based on this rapid review, a small proportion of pregnancy studies use placenta data in research. The placenta, an essential component of understanding healthy or adverse outcomes, deserves much more attention in pregnancy research.

Errors in search strategies used in systematic reviews and their effects on information retrieval

OBJECTIVES

Errors in search strategies negatively affect the quality and validity of systematic reviews. The primary objective of this study was to evaluate searches performed in MEDLINE/PubMed to identify errors and determine their effects on information retrieval.

METHODS

A PubMed search was conducted using the systematic review filter to identify articles that were published in January of 2018. Systematic reviews or meta-analyses were selected from a systematic search for literature containing reproducible and explicit search strategies in MEDLINE/PubMed. Data were extracted from these studies related to ten types of errors and to the terms and phrases search modes.

RESULTS

The study included 137 systematic reviews in which the number of search strategies containing some type of error was very high (92.7%). Errors that affected recall were the most frequent (78.1%), and the most common search errors involved missing terms in both natural language and controlled language and those related to Medical Subject Headings (MeSH) search terms and the non-retrieval of their more specific terms.

CONCLUSIONS

To improve the quality of searches and avoid errors, it is essential to plan the search strategy carefully, which includes consulting the MeSH database to identify the concepts and choose all appropriate terms, both descriptors and synonyms, and combining search techniques in the free-text and controlled-language fields, truncating the terms appropriately to retrieve all their variants.