OvulaRing studies & clinical evidence (DOI, PubMed, PDFs)

Last updated: 28 Jan 2026

Here we compile studies, white papers and validations on OvulaRing.

Evidence at a glance

key messages

  • Best evidence: Peer-reviewed publications show that continuous intravaginal core temperature measurement (OvulaRing) can be used to identify and predict the fertile window.
  • Particularly relevant for: Women who want to have children and doctors/endocrinologists who want to improve cycle diagnostics and the classification of temperature data in a clinical context.
  • Key limitations: Not all sources are equally reliable: posters/abstracts are often less detailed than full texts, and white papers are manufacturer documents—they explain the method but are no substitute for independent efficacy studies.

Classification according to evidence

  1. Peer-reviewed studies (highest significance)
  2. Conference papers / Posters (early evidence, often only abstracts)
  3. Doctoral theses / academic dissertations (In-depth analysis, methodologically sound, but usually not subject to journal peer review)
  4. White papers / Manufacturer documents (Methodology & examples, not independent)
  5. Secondary sources / Reviews (Classification within the field; effectiveness not necessarily specific to OvulaRing)

Note: This overview is intended to provide transparency regarding sources and is not a substitute for medical advice.

Further reading

Want to understand the studies? Here you’ll find information on methodology, medical details and the key quality criteria.

OvulaRing: An overview of scientific publications

Are you looking for academic sources on OvulaRing? Here you’ll find all the key publications – clearly organised, with brief descriptions and direct links (DOI, PubMed, PDF).

Note: This list is a list of sources, not medical advice. Go directly to:

1) Peer-reviewed studies (core evidence)

  1. Nolte J et al. (2026)
    Optimising basal body temperature measurement for cycle diagnostics: a comparison of different methods in female recreational athletes – Frontiers in Sports and Active Living.
    DOI: 10.3389/fspor.2025.1732233
    Study summary: OvulaRing & Ovulation detection: 7 study takeaways for female athletes
    🔎 Focus: Comparison of methods for detecting ovulation/temperature shifts in physically active women: continuous intravaginal core temperature (OvulaRing) vs. sublingual/ear/rectal (both at 06:00 & upon waking). Result: intravaginal 24-hour CBT most robust; sublingual at a fixed time as a pragmatic alternative; ear/rectal with high variability.
    Links: Publisher’s website (Frontiers) · PDF
  2. Regidor PA et al. (2018)
    Identification and prediction of the fertile window … using a vaginal biosensor – Gynecological Endocrinology.
    DOI: 10.1080/09513590.2017.1390737
    🔎 Focus: Ovulation/fertility window detection & prediction using continuous intravaginal core temperature measurement (OvulaRing).
    Links: PubMed · Publisher’s website
  3. Ekhart D et al. (2018)
    Dynamics of core body temperature cycles in long-term measurements … in women – Chronobiology International.
    DOI: 10.1080/07420528.2017.1375942
    🔎 Focus: Long-term measurements of intravaginal core temperature under everyday conditions (sensor/physiology perspective).
    Links: PubMed · Publisher’s website
  4. Goeckenjan M et al. (2020)
    Continuous Body Temperature Monitoring to Improve the Diagnosis of Female Infertility – Obstetrics and Gynaecology.
    DOI: 10.1055/a-1191-7888
    🔎 Focus: Diagnostics in fertility clinics (comparison of clinical monitoring vs. algorithm vs. ‘lowest daily temperature’).
    Links: PubMed · Full text (PMC) · PDF (Thieme)
  5. Goeckenjan M et al. (Erratum, 2023 online / 2020 issue)
    Correction: Continuous Body Temperature Monitoring … – Obstetrics and Gynaecology.
    DOI: 10.1055/a-2154-8645
    🔎 Focus: Correction/Erratum to the above-mentioned article.
    Links: PubMed · Thieme
  6. Alexander H. (2015)
    OvulaRing – The Cyclofertilogram (CFG) for precise cycle and fertility diagnosis – Ärzteblatt Sachsen (12/2015).
    🔎 Focus: Practical overview (concept/application; not a traditional randomised study design).
    Links: PDF

2) Conference papers / posters (scientific abstracts)

  1. Alexander et al. (2014)
    Fertility monitoring using a vaginal biosensor (OvulaRing©) – Obstetrics and Gynaecology (conference paper).
    DOI: 10.1055/s-0034-1388603
    Links: Thieme
  2. Schiwek E. et al. (2014)
    Diagnosis of luteal insufficiency … using continuous temperature monitoring (e.g. OvulaRing) – Obstetrics and Gynaecology (conference paper).
    DOI: 10.1055/s-0034-1388017
    Links: Thieme
  3. Regidor PA & Alexander H. (2018)
    Identification and prediction of the fertile window … (OvulaRing®) – Obstetrics and Gynaecology (Poster, DGGG 2018).
    DOI: 10.1055/s-0038-1671278
    Links: Thieme

3) PhD thesis (details on CFG/score and methodology)

  1. Komár, Marta Alicja (2019/2020)
    Ovula Ring® – A new method of cycle diagnosis … Cyclofertilogram … CFG score – University of Leipzig (Dr. med.).
    🔎 Focus: Comprehensive review/analysis (highly relevant for a ‘deep dive’, but not a peer-reviewed journal publication).
    Links: DNB entry · PDF (Repository)

4) White papers / manufacturer documents (not peer-reviewed, but frequently cited)

  1. Alexander H. et al. (2019)
    Cycle diagnosis and treatment monitoring for those wishing to conceive using the OvulaRing, cyclofertilogram (CFG) and CFG score – VivoSensMedical (white paper).
    🔎 Focus: CFG score, examples, classification; useful as a description of the method – but not to be equated with independent research findings.
    Links: PDF (DE) · PDF (EN)
  2. Feldmann U. (2014)
    Time of ovulation – continuous measurement of core body temperature … – *Der Privatarzt Gynäkologie*, Issue 5, pp. 18–19.
    🔎 Note: This title is listed as a reference in OvulaRing/VivoSens documentation; a freely accessible full text is often difficult to find online.
    Links: View reference in the white paper

5) Secondary sources (reviews / context – ‘How is OvulaRing classified?’)

A) HCI / User understanding & uncertainty

  1. Schneider H. et al. (2019)
    Communicating Uncertainty in Fertility Prognosis – CHI ’19 (ACM).
    DOI: 10.1145/3290605.3300391
    🔎 Focus: How to present uncertainty in fertility prognoses in an understandable way (UI/UX research; not primarily clinical efficacy).
    Links: ACM · PDF

B) Medical overviews

  1. Freundl G., Gnoth C., Krahlisch M. (2016)
    Menstrual cycle computers and apps – Gynaecological Endocrinology 14, 93–104.
    DOI: 10.1007/s10304-016-0065-3
    🔎 Focus: Classification of cycle computers/apps; outlines opportunities & limitations (good context for quality criteria).
    Links: SpringerLink
  2. Thieme A., Kalischewski P. (2018)
    Myasthenia Gravis: Family Planning, Pregnancy and Delivery – Neurology International Open (Review).
    DOI: 10.1055/s-0043-122651
    🔎 Focus: Review on family planning/pregnancy in myasthenia gravis; OvulaRing is mentioned as a cycle monitoring option.
    Links: Thieme · PDF
  3. Lyzwinski L. et al. (2024)
    Innovative Approaches to Menstruation and Fertility Tracking Using Wearable Reproductive Health Technology – JMIR (Systematic Review).
    🔎 Fokus: Wearables & Evidenzlage im Überblick; OvulaRing wird im Kontext anderer Devices eingeordnet.
    Links: JMIR · PubMed
  4. Yu JL et al. (2022)
    Tracking of menstrual cycles and prediction of the fertile window … via BBT & heart rate as well as ML algorithms – Reproductive Biology and Endocrinology.
    DOI: 10.1186/s12958-022-00993-4
    🔎 Fokus: Wearables/Algorithmen-Kontext (ML-Ansätze); nennt OvulaRing als Beispiel im Feld.
    Links: SpringerLink · PubMed

A quick tip on how to interpret this (for critical readers)

  • The strongest evidence comes from the peer-reviewed core studies (listed under point 1 above).
  • Abstracts/posters are useful, but are usually less detailed than full texts.
  • White papers explain the Method/CFG score, but are not a substitute for independent efficacy studies.

Frequently asked questions about the evidence for OvulaRing

Here we answer the most common questions about the scientific evidence for OvulaRing – based on the most important publications.

Which study/publication provides the strongest evidence for OvulaRing?

The strongest direct evidence for OvulaRing (in the sense of “detecting and predicting the fertile window / ovulation”) comes from the peer‑reviewed study by Regidor et al. in Gynecological Endocrinology. It is the central publication because it explicitly addresses the determination of the fertile window using a vaginal biosensor and an algorithm, and evaluated a larger number of cycles.

What exactly did the OvulaRing studies evaluate?

The studies essentially look at two things:
1) Fertile window & ovulation timing: Regidor et al. examine whether an algorithm based on continuously measured core body temperature (intravaginal) can identify and/or predict the fertile window.

2) Diagnostics in cycle/ovulation disorders: Goeckenjan et al. compare continuous temperature monitoring (vaginal sensor) with standard cycle monitoring (e.g., ultrasound/hormones) and discuss how it can be used in clinical practice.

In addition, there is research that focuses less on “fertility” as a goal and more on the measurement method itself (chronobiology / long‑term temperature trajectories).

What conclusions do the OvulaRing studies come to?

Regidor et al. report (according to the abstract) that the system evaluation achieves a retrospective “accuracy” of 99.11% for detecting ovulation (based on a stated software validation error of 0.89%) and that, prospectively, an accuracy of 88.8% is reported for a window “3 days before ovulation, day of ovulation, 3 days after ovulation”. In addition, the paper describes how the algorithm derives the fertile window from continuous intravaginal core‑temperature measurement.

How well can OvulaRing determine the fertile days?

The most frequently cited metric comes from the study by Regidor et al.:
It reports a prospective accuracy of 88.8% for a 7‑day window around the day of ovulation
(3 days before, day of ovulation, 3 days after).

Important for a fair interpretation: “accuracy” here means how well the algorithm matches the ovulation/window reference point defined in the study design – it is not automatically the same as “contraceptive safety” (e.g., Pearl Index from large, independent real‑world studies).

Where else is OvulaRing used in research?

OvulaRing appears in research mainly in three contexts:

Chronobiology / core‑temperature rhythmicity:
Long‑term measurements of core temperature in everyday life (e.g., to analyze circadian patterns).

Digital health & wearables (reviews):
Systematic reviews on fertility wearables mention intravaginal temperature devices as a device class.

UX/HCI research:
Studies such as “Communicating Uncertainty in Fertility Prognosis” examine how predictions and uncertainty are presented understandably – i.e., less “whether it is correct” and more “how users interpret the statement”.