Introduction

In the US, more than 2 million women reach menopause annually [1]. Of these women, nearly 50% will experience a constellation of symptoms as a result of declining estrogen levels in the vaginal epithelium and lower urinary tract, defined as genitourinary syndrome of menopause (GSM) by the International Society for the Study of Women’s Sexual Health and The North American Menopause Society [1, 2]. Symptoms of GSM may include vaginal dryness, dyspareunia, recurrent urinary tract infections, and urinary frequency and urgency [2, 3]. They may significantly impact the quality of life of menopausal and post-menopausal women [1]. Additionally, despite its high prevalence among women, GSM remains largely underdiagnosed and undertreated [4].

In 2016, the International Menopause Society (IMS) updated its guidelines on menopausal hormone therapy (MHT), emphasizing its role in GSM management [5]. Vaginal estrogen therapy is available in various formulations (cream, tablets, drug-eluting ring), allowing patients to select the option that best suits their preferences [6]. As this treatment option is increasingly prescribed, it is important to understand the patterns of how patients seek information for vaginal estrogen therapy. The objective of this study is to examine the correlation between public interest in vaginal estrogen, as reflected in Google search trends, and published medical literature on vaginal estrogen. The study aims to contextualize the relationship between scientific discourse and public interest in vaginal estrogen.

Materials and methods

Google trends

A retrospective analysis of Google Trends data was conducted to examine search interest in the term “vaginal estrogen” from 2017 to 2023. Search volume for this term was controlled by the inclusion of commonly searched words, namely “weather”, to account for temporal changes in the use of the Google search engine overall [7]. The rationale for selecting “weather” as a control term was based on its consistently high and stable search frequency across time, a method previously validated in similar epidemiological analyses [8]. The relative search volume was normalized as arbitrary units (au.) and was represented graphically. A time series analysis was conducted using a 6-month simple moving average to smooth short-term fluctuations and highlight broader trends in search interest. This smoothing was applied in Microsoft Excel after exporting the normalized data from the Google Trends platform. We also used Excel’s line fitting function to calculate the R² value, providing a basic measure of the strength of the linear trend in search interest over time. No additional statistical modeling or formal hypothesis testing was conducted, and the graphical analysis was intended to provide a descriptive visualization of temporal patterns in public interest related to vaginal estrogen.

PubMed

Search volume trends were compared to publication trends for journal articles indexed in PubMed using the Mesh term “vaginal estrogen.” The user’s left-hand side of the search engine provides a visualization of the number of articles published in PubMed every year, along with other advanced filter options. This data was adjusted appropriately to cover only the study timeline of 2017–2023, and the number of publications per year was recorded in a table and later graphed for a visual representation.

Google scholar insights

To gain insights into how vaginal estrogen is discussed in the scientific community, a literature review was conducted. The Google Scholar engine was used as it provided more direct and efficient data on citation value compared to PubMed literature. This second engine also provided a wider network of academic resources. Thus, utilizing the Google Scholar query engine, the ten most-cited articles published between 2017 and 2023 were identified using citation metrics (Table 1). These articles were isolated by conducting a restricted search of the term “vaginal estrogen” in the titles of articles published within the aforementioned time frame. The search was open to all types of articles, ranging from original articles to systematic reviews. The only criteria for inclusion/exclusion included the usage of the search term “vaginal estrogen” in the title and the year of article publication. We analyzed these studies for their objectives, findings, and relevance based on the abstracts. We organized the relevant literature in order from most cited to least cited for the top ten cited papers published between 2017 and 2023. To evaluate how the study topic aligns with broader scientific and public interests, the findings from key manuscripts were summarized to highlight prevailing trends in this treatment usage. These trends were then encapsulated into a single phrase that reflects the ongoing relevance and impact of the research.

Table 1 Ten most cited papers on vaginal estrogen during the 2017–2023 period.
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Results

Google trends

Google search interest in “vaginal estrogen” showed an overall increasing trend from 2017–2023, with a strong positive correlation (R² = 0.72, Fig. 1). Over the course of six years, there were no discernable patterns in regard to seasons, with instead a relatively consistent increasing trend. This general trend suggests growing public curiosity or concern regarding the use of vaginal estrogen, possibly reflecting heightened awareness or shifts in clinical recommendations during this time. Google Trends provides data on the subregions with the most search interest– the subregion with the highest interest in the country during this time was Maine.

Fig. 1
figure 1

Average monthly Google Trends searches for vaginal estrogen spanning from 2017–2023 in normalized au.

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PubMed

PubMed results indicated an increasing trend from 2017–2023 (Fig. 2).

Fig. 2
figure 2

Number of publications on “Vaginal Estrogen” found through PubMed annually from 2017–2023.

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Google scholar insights

Bibliographical analysis reveals that out of the top ten most cited papers on vaginal estrogen, nine of them came from the US [9,10,11,12,13,14,15,16,17] and one from Brazil [18]. Among these papers, the most mentioned and affiliated institutions included Brigham and Women’s Hospital of Harvard Medical School [9,10,11], UCLA [9, 11], and Stanford [11, 12]. JoAnn E. Manson is mentioned as a senior author in three studies [9,10,11], and no other senior author appears more than once within the top ten citations. In terms of funding, three studies received NIH grants mainly from institutes focused on cancer, aging, heart/lung diseases, and women’s health.

Discussion

The findings of the current study reveal a rising public interest in vaginal estrogen over the past six years, reflected in Google Trends data, [Fig. 1]. Additionally, the positive trend in the number of publications on “vaginal estrogen” demonstrates an overall increase in literature on the subject over the past six years [Fig. 2]. While these trends do not establish causation, the data suggests a concurrent rise in interest in this treatment method from the public and within the scientific community [Fig. 1, Fig. 2]. The increased awareness of vaginal estrogen therapy may be due to its low complication rate when compared to other menopausal treatments [11]. Vaginal estrogen allows clinicians to offer a range of approaches to address the symptoms of GSM including vaginal dryness, dyspareunia, and recurrent UTIs, ultimately improving their quality of life [2, 19]. Notably, with Google Search Trends, Maine had the highest proportion of search interest over the six years in the country compared to other states, potentially revealing interest in vaginal estrogen from less economically affluent regions [20]. Currently, Maine ranks 26th nationally for per capita personal income, which is considered a generally weak economic standing in the US [20]. Regions with less affluence may also have less access to healthcare, relying more on publicly accessible data to understand new medications or symptoms [21]. However, Maine’s slowly increasing Real Gross Domestic Product (GDP) may also contribute to its participation in more medical curiosity through increased economic participation [22].

The search for the top ten cited papers also provides insight into the rise of the popularity of vaginal estrogen since 2017. For 65 years up to 2016, there were a total of 192 articles published featuring “vaginal estrogen” in their title. While within the 6-year span between 2017–2023, 131 articles were released. This highlights that around 40% of the literature on this topic has emerged in recent years, reflecting the nearly doubling of work on vaginal estrogen. This surge in popularity may be attributed to recent studies demonstrating that low-dose vaginal estrogen is an effective treatment for GSM, with evidence indicating no increased risk of breast cancer recurrence or endometrial cancer [23]. This aligns with a growing effort to challenge the FDA’s black box warning on vaginal estrogen products [23]. Additionally, Crandall et al. [11], which was the most cited study, found that postmenopausal women on vaginal estrogen therapy did not have an increased risk of coronary heart disease, fracture, all-cause mortality, and other global index events compared to non vaginal estrogen therapy users. Based on our study, we predict that vaginal estrogen’s popularity will continue to increase in academia and among the public. The systematic review by Pinkerton et al [10] emphasizes that although distinct types of vaginal estrogen formulations – such as (creams, tablets, and rings) are effective, GSM remains an undertreated condition.

Simultaneously, three of the ten papers received funding that was supportive of the research, allowing for larger cohort data collection and more advanced studies such as mechanistic tissue studies [9, 11, 15]. Additionally, although the majority of studies took place in the US and in US institutions, there are efforts from around the world such as in Brazil that are contributing to the relevance of vaginal estrogen research [18]. One senior author, JoAnn E. Manson, was mentioned in three of the ten papers, with no other senior author appearing more than once [9,10,11]. This provides insight into a pattern of which researchers publish more often, and in general, whether these researchers are more interested in women’s health subjects, which are notable motivations to consider as a reader.

Google Trends is a powerful tool for collecting real-time data, has a wide reach across the nation spanning searches, and acts as a relevant indicator of public awareness and curiosity. Some limitations to consider with Google Trends in data analysis, however, are that although it reveals public interest and “hot spots” with a high concentration of searches in certain regions of the country, it does not provide detailed demographic information for further analysis. This highlights potential demographic and socioeconomic biases in the search engine that do not take into consideration the differences in digital literacy, demographic information of the searchers, and the level of digital literacy amongst users. This may contribute to selection bias in the study as well, as data was pulled only from those with Internet access and simultaneous use of the Google Engine, as opposed to competing search tools such as Yahoo, Bing, etc.

Additionally, with PubMed literature, it is difficult to tell whether the timing of conducted studies and external searches by researchers for their work may have influenced the fluctuations in Google Trends interest over the past six years. The growth rate of academic publications appears to outpace public search interest. While vaginal estrogen research has expanded significantly, Google Trends data suggests a more modest increase in public engagement. This discrepancy may indicate challenges in accessing information, persistent stigma around vaginal health or hormone therapy, or a lag in public response to scientific progress.

Conclusion

The study demonstrates a noteworthy connection between the rising medical recommendations for vaginal estrogen in the management of GSM symptoms, the growing search interest for the term “vaginal estrogen” on Google, and the rising publication of scientific literature on menopausal treatment for women. This underscores that greater clinical endorsement of vaginal estrogen may contribute to public engagement, though further research is needed to determine whether academic discourse directly influences public interest, or vice versa. Additionally, it highlights how developments in scientific research may contribute to the legitimacy of a treatment option and a more confident prescription of it.

The correlation between increasing publication rates and public interest in GSM suggests a shared rise in awareness. Future research should examine the breakdown of how social media may influence public interest through research engines like Altmetric, and whether these increased search trends translate into higher prescription rates and improved patient outcomes. Additionally, the cost-effectiveness of vaginal estrogen in comparison to other estrogen and menopausal therapies should be explored, as well as its accessibility across diverse demographics in the US, ensuring equitable access for all postmenopausal women.