infertility is an important health problem , with an estimated prevalence of 48.5 million couples worldwide ( 1 ) . although infertility is mostly common in aging populations and in urban areas where women have their first child at an older age , the burden of infertility and its social consequences are predominantly found in developing and transitional countries ( 2 ) . in response to the increasing rates of infertility , rapid progress in reproductive medicine and research has been largely attributed to significant developments and novel technologies in the treatment and care of infertile couples in the world ( 3 ) . in this context , assisted reproductive technologies ( arts ) have been widely recommended as successful and common treatments in most countries . arts include a wide range of treatments or procedures involving in vitro handling of human oocytes , sperms or embryos for establishing a pregnancy(4 ) . in vitro fertilization ( ivf ) and its extended technologies , such as intracytoplasmic sperm injection ( icsi ) , pre - implantation genetic diagnosis ( pgd ) , and cryotechnology , are among the most common arts worldwide . it is estimated that more than half a million ivf cycles are performed annually in the european countries , resulting in 100,000 new - borns ( 3 , 5 , 6 ) . the total number of successful ivf and icsi births worldwide was reported as 5 million cases in 2012 ( 7 ) . with respect to worldwide recognition and increased demands for art services , high quality research and key publications are still required to develop these technologies in developing countries . although the number of journals and publications in the field of reproductive medicine has increased dramatically in recent years ( 3 , 8) , much regional and country variation is in progress . global research on arts has been highly concentrated among the world s richest countries while developing countries have indicated the least contribution to the research on arts and reproductive technologies ( 9 , 10 ) . as research on arts has been distributed disproportionately among countries , further investigations are needed to explore these patterns between and within countries . indeed , previous analyses have identified trends and the geographical distribution in the field of clinical reproductive medicine ( 3 , 9 , 11 ) . collaboration networks ( 12 ) and the most cited articles ( 8 , 13 , 14 ) have also been investigated to some extent . although research is the key driver for developing arts in communities , it has remained neglected or ranked low on national research priorities in developing countries ( 15 ) . therefore , national evaluations are required to evaluate the research productivity and its attributes for the purpose of making research policies and priorities within countries . in an attempt to address these challenges , the present study aimed to provide detailed information on global research publications on arts between 1998 and 2014 in the medline database . further analysis has been made to compare the research performance between the leading countries in the field using bibliometric techniques . the present study illustrates the patterns of global research on infertility involving different technologies implemented for the purpose of treatment and care of infertile couples . it also helps obtain a comprehensive and up - to - date perspective of this field to better understand the contribution of international scientists to the global art research . the present study s findings tend to help policymakers evaluate the research performance of scientists within and across borders . in march 2015 , the medline database was searched for research publications indexed under the medical subject heading ( mesh )  reproductive techniques , assisted ( including the following mesh headings : in vitro fertilization ; intracytoplasmic sperm injections ; cryopreservation ; and ovulation induction ) , with the following expressions in the fields of title or abstract : intrauterine insemination ; sperm donation ; embryo / egg donation and surrogate mothers . the number of research publications in the medline database was recorded for each individual year , from 1998 to 2014 , and for each country . the affiliation of the corresponding author was used to identify affiliation of a research publication to a country . the first year used for the search was 1998 to ensure the ability to retrieve reliable data on authors and countries affiliations from the medline database . the following countries were arbitrarily selected for data retrieval : united states , united kingdom , france , germany , canada , italy , japan ( g7 countries ) , brazil , russia , india , china ( bric countries ) , egypt , turkey , israel and iran . data for the global burden of infertility were extracted from the who disability - adjusted life - year ( daly ) estimates for 2012 . the semantic word mapping technique was implemented to identify major domains using vosviewer software ( version 16.0 ) . in total , 96,739 articles were published in the medline database between 1998 and 2014 . trends in global research publications on arts have shown that art and cryopreservation experienced dramatic growth in the number of publications . the absolute number of research publications for each art from 1998 to 2014 ranged from 71 ( sperm donation ) to 20277 ( art ) , with a median of 2451 . the top techniques according to the absolute number of publications were art ( 20277 ) , ivf ( 11209 ) , cryopreservation ( 11623 ) , ovulation induction ( 4352 ) , and icsi ( 2960 ) . the major research domains of selected countries in the field of arts are illustrated in figure 1 . in this graph , the absolute number of research publications for each country from 1998 to 2014 ranged from 75 ( russia ) to 11674 ( us ) , with a median of 2024 . the top five countries according to the absolute number of publications were the us ( 16453 publications ) , the uk ( 5427 publications ) , japan ( 4805 ) , china ( 4660 ) and france ( 3795 ) . according to these data , the us is the major producer of art research in the world , having many more publications than other countries . figure 2 illustrates the distribution of the global burden of infertility and the share of research publications for selected countries . in this graph in total , 96,739 articles were published in the medline database between 1998 and 2014 . trends in global research publications on arts have shown that art and cryopreservation experienced dramatic growth in the number of publications . the absolute number of research publications for each art from 1998 to 2014 ranged from 71 ( sperm donation ) to 20277 ( art ) , with a median of 2451 . the top techniques according to the absolute number of publications were art ( 20277 ) , ivf ( 11209 ) , cryopreservation ( 11623 ) , ovulation induction ( 4352 ) , and icsi ( 2960 ) . the major research domains of selected countries in the field of arts are illustrated in figure 1 . in this graph , the absolute number of research publications for each country from 1998 to 2014 ranged from 75 ( russia ) to 11674 ( us ) , with a median of 2024 . the top five countries according to the absolute number of publications were the us ( 16453 publications ) , the uk ( 5427 publications ) , japan ( 4805 ) , china ( 4660 ) and france ( 3795 ) . according to these data , the us is the major producer of art research in the world , having many more publications than other countries . figure 2 illustrates the distribution of the global burden of infertility and the share of research publications for selected countries . in this graph the evaluation of the research literature in the art field indicated regional and country variations . global research on arts was geographically distributed and highly concentrated among the world s richest countries , particularly the us , the uk and japan . further inspection of data indicated the major semantic clusters of research literature published by selected countries . according to our findings , this trend was previously observed in similar investigations ( 3 , 11 , 16 ) . however , this growth followed different patterns within different art domains , as art , ivf and cryopreservation indicated significant progress over the years . our findings indicated that cryopreservation and ivf were the most productive research domains among arts . preliminary investigations suggested that art and ivf are the most cited research domains among reproductive medicine literature ( 3 ) . these technologies , which enable scientists and physicians to use frozen stored sperm , oocytes , embryos , and testicular and ovarian tissues , are also among the most common and successful treatments in the world . the broad provision of these technologies has potentially increased the chance of extended research on these domains . although art and ivf research literature indicated upward trends over the years , a detailed analysis revealed the global shift from developing new infertility interventions towards more in - depth analysis of the health implications for mothers and their children ( 3 ) . however , further analysis is required to investigate the characteristics of other arts , such as egg or sperm donation , that are potentially restricted in some countries due to legal and social issues , particularly in developing and transitional countries . our analysis also indicated the share of g7 and brics in the global art research . these findings are consistent with early evidence suggesting that g7 countries are the major sources of art research in the world ( 16 ) . the highest level of research productivity has been reported by the united states , with a 21.82% share of the global output . the united kingdom ranked second with 9.78% , followed by italy ( 7.98% ) , turkey ( 5.19% ) and china ( 4.33% ) ( 16 ) . this study has revealed many regional and country variations in the research literature published in the medline database . previous studies have indicated significant variations among the rich countries , especially in europe , in art research output due to legal restrictions affecting the practice of arts in some countries ( 17 , 18 ) . these restrictions have not only influenced the type of research performed , but also the amount of research data published ( 11 ) . other empirical studies have also suggested the availability of financial funding as a key driver of art research in the world ( 11 ) . for most developing countries , although optimal utilization of ivf has been estimated to be around 1500 cycles per one million people per year , the provision of such services has declined significantly in developing countries ( 15 ) . indeed , the contribution of developing countries to global art research has remained limited due to the lack of infrastructures and financial resources . in addition , infertility prevention , treatment and care have been neglected , ranking low on the research priorities , particularly in developing countries ( 15 ) . first , with current methodology , every publication is affiliated with a single ( the corresponding ) author . however , in the case of international collaborations , different countries are involved . searching other databases such as scopus or web of science may lead to different results . however , mesh headings are only available through the medline and pubmed interfaces . in summary , global research on arts has been geographically distributed and highly concentrated among the world s richest countries . further investigations into the causes and characteristics of less common arts research are required to foster art research in developing countries .