El human papilloma virus (HPV) It is implicated in most cases of cervical cancer, which is why virus detection tests are a key part of screening programs. Even so, Not all women participate in these reviews by fear of paindiscomfort, stigma or simply lack of information, something that is also observed in Spain and other European countries.
Given this context, a team from Zhongnan Hospital of Wuhan University has focused on a less invasive alternative: a test to detect HPV in menstrual blood collected during menstruation with a small, special compress. The study was published in the medical journal The BMJThis suggests that this approach could become a complementary approach to increase access to screeningespecially among those who avoid gynecological consultations.
A massive study with more than 3.000 women
The trial was conducted in the Chinese province of Hubei and included 3.068 women between 20 and 54 years old, all with regular menstrual cycles, recruited in four urban and three rural areas between September 2021 and January 2025. This is a large community study, designed to directly compare the new technique with the conventional cervical sampling.
Each participant submitted three types of samples to analyzeFirst, menstrual blood collected with a mini sanitary pad (a small sterile cotton insert attached to the absorbent area of ​​a standard sanitary pad), considered the index test. Second, a cervical sample obtained by a healthcare professional as a reference for comparison. Finally, an additional cervical sample was taken for further processing in the laboratory.
To facilitate participation, women were able to use a mobile application integrated into WeChat, called Early Testwhere they could consult the results and receive advice from healthcare professionals. This technological integration, according to the authors, It sped up response times and improved communication, something that could be extrapolated to European health systems with widespread mobile phone penetration.
At the heart of the study was the comparison between menstrual blood and cervical samples in the detection of high-grade precancerous lesions, known as CIN2+ and CIN3+which often require treatment to prevent progression to cervical cancer.
How the test works and what it actually measures
The new technique consists of analyzing the HPV genetic material (DNA or RNA) present in menstrual blood that leaks from the cervix and genital tract. As with other samples, such as cytology or vaginal self-samples, the goal is to identify the presence of the virus before it causes significant cellular changes.
The researchers established the following as the main indicators: sensitivity and specificity of the test. Sensitivity reflects how many people with the disease are actually detected by the test, while specificity indicates how many healthy people are correctly identified as negative, avoiding false positives.
The samples obtained with the minicompress (known in the study as Minipad) showed a 94,7% sensitivity for detecting CIN2+ lesionsThis figure is practically equivalent to that observed with cervical samples taken by professionals, which reached 92,1%. In other words, the menstrual blood test It was not far behind when it came to finding high-grade injuries.
With regards to specificityThe performance was slightly lower for menstrual blood: 89,1% compared to 90% of the cervical sampleHowever, the piece of information that offers the most reassurance to patients is the negative predictive value (the probability that a negative result actually means absence of disease), was virtually identical for both methods, settling around 99,9%.
El positive predictive valueThat is, the probability that a positive result corresponds to a true CIN2+ lesion also remained very similar: 9,9% in the case of menstrual blood versus 10,4% in the cervical sampleSimilarly, the need for referral to further examinations such as colposcopy was comparable, with approximately 10 referrals for each high-grade lesion detected in both groups.
Potential advantages: convenience and access to screening
Beyond the figures, one of the main strengths of this proposal is its non-invasive and home-basedThe possibility of using a specific sanitary pad during menstruation and sending it to the laboratory could help many women who currently avoid screening, whether in Spain, other European countries, or in less resource-constrained settings, to get tested. encourage participation in screening programs.
In the publication, the lead author, Zheng HuShe emphasizes that this strategy would make it easier for women collect the sample at home without the need for a gynecological examinationFor those who feel embarrassment, fear of pain, or distrust of the healthcare environment, this option is presented as an intermediate path between doing nothing and going to a consultation.
The study results support the idea that menstrual blood can act, like other cervicovaginal fluids or urine, as vehicle of cells and viral particles from the genital tractTherefore, the analysis of this fluid opens the door to expanding the range of screening methods without the need for gynecological instruments.
Another point the authors emphasize is the technological integrationThe combination of home sample collection with a mobile app to receive results and medical advice could fit well with the reality of many European systems, where digital tools are increasingly used to manage appointments, reminders and test results.
According to the Wuhan team, the data obtained in this cohort support the possibility that, in the future, HPV tests based on menstrual blood could be more effective. are integrated into the screening guidelines of cervical cancer as an alternative or even as a substitute in certain contexts, provided that new studies confirm these findings.
What the experts in Spain think
Although the Chinese group's conclusions are optimistic, The European scientific community urges cautionSeveral specialists in gynecologic oncology and HPV screening, consulted by scientific media, consider the work an interesting contribution, but agree that there is still does not justify immediate changes to screening programs current.
To Marta del Pino, gynecologist at the Gynecological Oncology Unit of the Hospital ClÃnic of Barcelona and scientific coordinator of ICGON, the research demonstrates that HPV detection from menstrual samples using mini-pads offers a sensitivity very similar to that of cervical sampling conventional in the identification of CIN2+ lesions. Furthermore, it highlights that the high negative predictive value provides a high clinical confidence upon receiving a negative result.
However, Del Pino insists that this test cannot be interpreted as a immediate replacement of current screening protocolsAmong the limitations, it notes that the study only includes women who menstruate regularly and uses a prototype device not available on the marketIt also notes that not all participants with negative results underwent biopsy, which may introduce verification bias and to seemingly inflate the test performance.
Another point the specialist highlights is that, when collecting material from genital tractThe test could detect HPV infections located outside the cervix, which would increase the number of false positivesIn the general population, he adds, the positive predictive value of any HPV-based strategy is limited, so Not all positive results imply the existence of a precancerous lesion.
Along these lines, Del Pino emphasizes that before considering a real incorporation into clinical practice, it would be necessary implementation studies in diverse contexts, direct comparisons with other self-collection methods already available (such as vaginal self-sampling) and analysis of cost-effectiveness and healthcare organizationIn other words, we would need to see how this method fits into the established systems in countries like Spain.
Doubts, drawbacks and limitations of the method
The prudent view is not exclusive. Xavier Bosch, emeritus researcher at the Catalan Institute of Oncology (ICO) and IDIBELL, also sees the work as pioneering but still experimentalIn their view, the key lies in determining whether menstrual blood offers performance truly comparable to that of HPV DNA tests on established samples, such as cytology, vaginal self-samples, or urine, or whether it simply It adds complexity without providing a clear benefit..
Bosch points out that one of the remaining technical challenges is to demonstrate the presence of blood. It does not interfere with the measurement of viral markersThis is a problem that already caused headaches in the first PCR tests. From their perspective, the field of HPV screening now has reliable and widely validated toolsTherefore, incorporating menstrual blood could generate more noise than advantages if a clear added value is not demonstrated.
He seems more skeptical Pluvio CoronadoProfessor of Obstetrics and Gynecology at the Complutense University of Madrid and head of section at the San Carlos Clinical Hospital. Although he acknowledges that the idea is innovative, he believes it has low probability of mass implementation in population screening programs.
Coronado points out several important practical limitations. To begin with, this type of test requires the presence of menstrual bloodWhile screening programs generally extend to age 65, an age after which many women no longer menstruate. Also, remember that use of hormonal intrauterine devices (such as Mirena and others) and long-acting contraceptives cause a considerable number of women to stop menstruating regularly.
Furthermore, the method cannot be applied in pregnant womenwhich also require specific monitoring, and that the healthcare system is already geared towards vaginal self-sampling as a non-invasive strategy with a performance very similar to that of professional collection. Coronado recalls that a similar approach was attempted with urine samples and that, in practice, It did not end up becoming established as a standard screening option.
How does it fit with current screening options in Europe?
In Spain and much of Europe, cervical cancer screening relies primarily on two tools: the cervical cytology and molecular tests of direct detection of HPV DNAMany programs already consider the possibility of women undergoing a procedure. vaginal self-sampling at homewhich is then analyzed in the laboratory using highly sensitive PCR techniques.
These strategies have a extensive evaluation track record and are supported by international guidelines. The main objective is to identify the presence of high-risk HPV types, such as genotypes 16 and 18which are most frequently associated with cervical cancer and other anogenital tumors. In Spain, the average prevalence of HPV infection in women is around 14,3%reaching figures close to 29% in the 18-25 age groupThis illustrates the importance of maintaining well-organized screening programs.
In this context, urine has also been studied as a possible alternative sample, although the results are more variable and, in many studies, the specificity is somewhat lower than in tests based on cervical samples or vaginal self-samples. For now, most recommendations consider urine a promising but still developing option.
The proposal regarding menstrual blood would therefore be added to a growing catalog of potential screening methodsHowever, in order for it to occupy a stable place in European protocols, it would have to demonstrate clear advantages in terms of participation, diagnostic accuracy, cost-effectiveness, and logistics compared to the alternatives already implemented.
Furthermore, practical issues such as the manufacturing and distribution of the mini-towel type device, the collection and transport of samples, the standardization of laboratory procedures and the coordination with existing care circuits in public health systems.
For now, the main value of this study lies in open a new avenue of research This could be especially interesting in settings where women face significant barriers to physically attending consultations, but without immediately displacing screening methods that have already proven effective in reducing cervical cancer mortality.
Taken together, the Chinese research provides solid data on the feasibility of detecting HPV using menstrual blood and suggests that the performance is comparable to that of the traditional cervical intakewith an attractive profile of comfort and accessibility. However, the specialists consulted in Spain point out that, although the approach seems promising and could add options in specific cases, more is still needed. further studies, international validation, and real-world analysis before this test can be considered as a routine part of screening programs in Europe.
