Worldwide research productivity in emergency contraception: a bibliometric analysis

Background The main goal of this study was to assess worldwide research activity in emergency contraception (EC) using bibliometric indicators. Methods Data in SciVerse Scopus were searched for documents pertaining to emergency contraception. Data obtained were then exported to Microsoft Excel and analyzed using Statistical Package for Social Sciences. Results A total of 2142 documents were published about EC worldwide. Documents were written in 27 different languages and were published from 78 countries. Publications in EC started on late 1960s. Total number of citations for published EC documents was 30154 while median citation per document was six. The h-index of the retrieved documents was 58. The leading country in EC research was United States of America with a total of 559 documents (26.10%). One hundred and ninety five (9.10%) documents were published in Contraception journal. The leading institution in EC research and publications was Princeton University (50; 2.33%) followed by University of California, San Francisco (34; 1.59%). Conclusions The present data revealed that there is a worldwide increasing interest in EC research. Willingness of health policy makers to make EC accessible to the public will determine the future of EC research activity and future of EC as a contraceptive method.


Background
Contraception-related research has gained a lot of attention in the past few decades. The growth of population, rights of women to choose the time of motherhood, high prevalence of HIV disease, as well as the strong religious and political debate about abortion has created more attention and research momentum toward contraception science [1][2][3][4]. Furthermore, the economical and emotional burden of high rates of unintended pregnancies (UP) had drawn more attention and interest in novel and practical contraceptive methods. Historically speaking, women tried several behavioral and traditional contraceptive methods to avoid UP [5]. Currently there are several different natural, hormonal, mechanical and surgical methods for contraception that made a significant worldwide reduction in UP and illegal abortion [6][7][8]. However, despite the great advancement in contraception science and technology, no contraceptive method is 100% effective in preventing pregnancy all the time [9][10][11]. Furthermore, women might have sexual intercourse at unexpected times or they might be forced to have sex such as in rape situations. A practical contraceptive choice for women in such situations is the use of emergency contraceptive (EC) method. There are two main types of EC methods; emergency contraceptive pills (or called morning-after pill) and Intra Uterine Devices (IUD) that are sometimes used for the purpose of EC [12][13][14][15]. Emergency contraceptive pills are available as combined estrogen and progestin pills or progestin-only (levonorgestrel) pills, or antiprogestin (ulipristal acetate or mifepristone) pills [16][17][18][19]. In early 1970s, Dr. Albert Yuzpe was the first to prescribe birth control pills for emergency contraception [20]. In 1998, the FDA approved the marketing of the first EC product. One year later, the FDA approved the first progestin-only EC named Plan B® [21,22].
Many review articles have been published about different types of contraceptive methods including emergency contraception [23][24][25]. However, scanning the literature showed no bibliometric studies about any type of contraceptive methods had been published. In contrast, hundreds of bibliometric studies in various medical fields and from different parts of the world had been published. Therefore, the goal of this bibliometric study was to assess the quantity and quality of EC-related research worldwide. Such a study will give insight into the current state of EC field. Furthermore, this study will provide baseline data for future similar projects in the field of contraception bibliometrics. So, in this study, we will give researchers in the in reproductive and family planning field an informative description of published literature about EC.

Search strategy
SciVerse Scopus, developed by Elsevier, was searched for data pertaining to EC. The choice of Scopus database was based on the fact that it is one of the largest available databases. In this study, title search strategy was applied. All subject areas in Scopus search engine including health sciences, social sciences, life sciences and physical sciences, were selected. The date range of the study was all years up to December 31st 2012. This time interval was selected to account for the time delay between the date an article is published and the date it appears within the Scopus database. Articles published after December 31st, 2012 were not consistently present within the database compared to earlier published articles., therefore articles after this date were excluded from statistical analysis. The key words used in the search query were those pertaining to emergency contraception. These key words were made after extensive review of published literature about emergency contraception. We used the following keywords: emergency contraception or postcoital contraception or morning-after-pill or emergency contraceptive pills or emergency hormonal contraception or postcoitus or post-coital contraceptive or Yuzpe or Plan B or Ulipristal acetate or levonorgestrel or intrauterine or IUD. These key words must be within articles that have the following phrase within Title/Abstract/keywords: "emergency contraception". The key words or phrases used in search engine were related to emergency contraception. These key words were present in recent review articles about emergency contraception. Documents that were published as erratum were excluded. Scopus search engine has a function that gives a summary of the types of published documents. The authors did not do a manual search for erratum documents; rather, it was given by Scopus database itself.

Indices of research productivity
Data were presented as rank order using the standard competition ranking (SCR). Only the ten top-ranked items were presented. The h-index, a marker of quality, was also presented. The h-index is the number of articles (h) that have received at least h citations [26]. Quality indicators considered for the top-ten ranked journals were the journal impact factor (IF) which was evaluated using the Journal Citation Report (JCR; Web of Knowledge) 2012 science edition by Thomson Reuters (New York, NY, USA) while the second indicator was the SCImago Journal Rank (SJR) indicator (Available at: http://www.scimagojr. com/SCImagoJournalRank.pdf).

Ethical approval
The Institutional Review Board (IRB) at An-Najah National University considers that such study does not require an IRB application and approval since no human subjects are involved.

Statistical analysis
Data from Scopus were exported to Microsoft Excel® and then transferred to the Statistical Package for Social Sciences, Version 15 (SPSS; SPSS Inc., Chicago, IL, USA) program for analysis. Categorical variables were expressed as Frequency and percentages. Categorical variables include document type, top 10 countries, institutions, authors and journals.

Discussion
Appropriate use of contraceptive methods requires an understanding of how scientific research about efficacy and safety of various contraceptive methods has progressed. One method to assess past and current status of a  particular medicine or procedure is to assess research output. As planned motherhood is now a pre-requisite for successful pregnancy and maternal health, emergency contraception has become more of a necessity for women [37][38][39]. Our study investigated research productivity about emergency contraception up until the year 2012 using Scopus as a search engine and as a source database. The total number of emergency contraception documents retrieved and analyzed using the methodology stated was 2142. This number represents a close approximation of worldwide research productivity in the field but definitely does not represent 100% of global publications about emergency contraception. Scopus is considered a trustful and powerful search engine with citation analysis. However, not all journals are indexed in Scopus and therefore publications pertaining to emergency contraception in these un-indexed journals were not counted. Nevertheless, this study and up to the author's best knowledge is the first to do a bibliometric analysis of worldwide contraceptionrelated research. The finding that the hindexed of published emergency contraception documents is 58 indicates that there is a large audience of these published documents and citation in the regard is relatively high.
There is a debate about the use of h-index as a marker of research quality. The h-index is commonly used instead of other simple bibliometric indicators like total number of papers or total number of citations. The h-index simultaneously measures the quality and quantity of scientific output. However, h-index measured using different databases can give different values and therefore each database has pros and cons when measuring the h-index [40][41][42]. Our study showed that several non-academic institutions, particularly non-profit organization, ranked among top 10 in emergency contraception research indicating that emergency contraception is a an issue of increasing interest from a demographic and family planning point of view. In addition, debate about emergency contraception and its potential abortion effect gave further momentum to research in this field. Some academic institutions have run an online website for emergency contraception awareness and directions [43]. Other institutions, like Population Council in Mexico, have dedicated their efforts to improve reproductive health through high-quality research in family planning, pregnancy-related problems including women's rights to safe and legal abortion [43]. Of the top cited documents in emergency contraception, it was clear that research groups in Edinbrugh, UK and Geneva, Switzerland have produced highly citable documents in EC field.
Our study further showed that although the prevalence of UP, HIV and sexual assaults that included rape incidences were high in Africa during civil wars, the EC research in Africa remained low [44][45][46][47][48]. South Africa has some research contribution in EC research that addresses awareness and services pertaining to emergency contraception [49][50][51][52][53]. In contrast to other world regions, EC research is limited in Arab Muslim countries in the Middle East. A  study indicated that awareness of women in Arab world regarding emergency contraception methods was very low [54]. Another study indicated that in contrast to English EC website users, the users of Arabic EC web sites were interested in the different aspects of EC than English website users [55]. The authors of the study suggested that there is a need for creating culturally specific EC website content for health education [55]. The future of emergency contraception seems promising given the upward increase in research output in the field. In the past 2 decades, the number of documents in EC has increased 20 folds. The popularity and future market and clinical use of EC seems to depend on various factors including religious and political debate in addition to safety and efficacy reports. Several studies have suggested that making EC methods available will positively affect the population growth and will make the future of such method more convincing [56,57]. Definitely, the arguments concerning the mechanism of action of emergency contraception, particularly those pertaining to mifepristone, ulipristal acetate and levonorgestrel which act by inhibiting ovulation rather than implantation will overcome many religious barriers for use of EC [58]. The time course and clinical experience with emergency contraception in the past 30 years or so have shown a good safety profile of emergency contraception given to women a second chance to terminate an unwanted pregnancy [59]. Our study has few limitations that need to be listed. First of all, we used Scopus database and therefore documents published in non-Scopus-indexed journals were not included. Another limitation is that some articles did not contain the selected key words has been excluded. Therefore, the number of publications analysed in this study might not represent 100% of EC-based worldwide research activity. It should also be noted that the research output for certain institutes could have been under-estimated due to different English spelling in different articles. Therefore, such institutes might have two or more institute's profiles in Scopus because their names were written differently in different documents. Finally, some documents might be counted twice especially those presented as conference material and then published as original research articles.

Conclusion
The present data reveal a good bulk and rising trend of research activity about emergency contraception. As expected, the quantity of EC research activity was skewed toward USA and European countries. However, centres in Latin America and India have made good contribution to research in EC. Research activity and use of EC can be improved by increasing awareness and acceptability of such method among women and health policy makers.