An interventional study of Sparrow Link and Sparrow Link (Sham) in Heavy Menstrual Bleeding, sponsored by Spark Biomedical, Inc.. Recruiting at 1 site in United States. Open to female participants aged 14 Years to 45 Years. Per ClinicalTrials.gov, last updated 2026-10-20.
Sponsored by Spark Biomedical, Inc. · Not applicable, Interventional, and Treatment
The LUNA study is a prospective, randomized, double-blind, sham-controlled, decentralized clinical trial in participants with heavy menstrual bleeding of no known structural cause. The study includes two age-based cohorts: adolescents aged 14-21 and adults aged 22-45. Participants in both cohorts will be randomized to receive transcutaneous auricular neurostimulation (tAN), which targets the auricular branch of the vagus nerve (ABVN) and the auriculotemporal nerve (ATN), or sham stimulation. Participants will be enrolled into the study over the course of five menstrual cycles. All study activities will occur remotely and in addition to participants' typical treatment for HMB (as allowed by the eligibility criteria).
During the first two consecutive menstrual cycles (M1 - M2, "Baseline Phase"), no tAN treatment will be delivered. Participants will estimate blood loss using the Pictorial Bleeding Assessment Chart (PBAC), and menstrual cramp pain will be assessed with a Numerical Rating Scale (NRS), daily throughout the duration of the menstruation phase of their two baseline menstrual cycles. Menstrual symptoms will be assessed using the Cox Menstrual Symptom Scale (CMSS) and a general quality of life assessment will be conducted on the final day of menstruation using the RAND Short-Form 36 (RAND-36). Menstrual-related quality of life assessments will also be conducted on the final day of each menstruation using the Menstrual Bleeding Questionnaire (MBQ) in the adult cohort, and the adolescent version (aMBQ) in the adolescent cohort.
During the following three menstruations (M3 - M5, "Treatment Phase"), participants will self-administer one 2-hour sham or active tAN session daily, beginning Day 1 of menstruation through the final day of menstruation in each menstrual cycle. Blood loss (via the PBAC) and menstrual cramp pain (via the NRS) will be assessed daily throughout the duration of each menstruation. Quality of life will be assessed with the CMSS, RAND-36, and the MBQ (adults) or aMBQ (adolescents) on the final day of each menstruation. A device usability survey will be completed at the end of M3 and M5. Participants will exit the study after the final day of M5.
206 studies on the registry are indexed under Menorrhagia; 35 are open to participants now.
This study's planned enrollment of 80 is below the median of 95 across 149 interventional studies indexed under Menorrhagia.
Browse Menorrhagia studies →Spark Biomedical, Inc. is the lead sponsor of 13 studies on the registry; 3 are open to participants now.
Of its 8 completed or terminated interventional studies of FDA-regulated products, 1 (13%) have results posted.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
In the Treatment Phase (M3-M5), participants will self-administer one two-hour session of active transcutaneous auricular neurostimulation (tAN) each day of menstruation.
Device: Sparrow Link
In the Treatment Phase (M3-M5), participants will self-administer one two-hour session of sham transcutaneous auricular neurostimulation (tAN) each day of menstruation. Participants in the sham group will apply the earpiece and connect the cable to the Patient Controller. The device will be turned on, and appears to function identically to an active device, but will not deliver stimulation through the earpiece.
Device: Sparrow Link (Sham)
The Sparrow Link will be using the components of the Sparrow Ascent device: (FDA-cleared K230796) a wearable, battery-operated, neurostimulation system designed to transcutaneously stimulate nerves on and/or around the auricle.
Also known as: Transcutaneous Auricular Neurostimulation
Participants will have the earpiece applied and the cable connected to the Patient Controller, but tAN stimulation will not be turned on. The sham device has an identical appearance to the active device.
Also known as: Transcutaneous Auricular Neurostimulation (Sham)
Pictorial Bleeding Assessment Chart (PBAC)
The PBAC is a widely accepted tool for patients with HMB to account for menstrual blood loss. Menstrual blood loss is estimated through a selection of images of tampons, pads, clots, and flooding events. Users mark a tally next to the images that best match each the saturation level of the menstruation products they used that day. PBAC data will be recorded by the participants for each calendar day (00:00-23:59 local time). Day 1 is the calendar date on which a menstrual product is first used. This trial will utilize a modified version of the Higham PBAC, where a tally system will be added to each of the images.
Time frame: Daily throughout all five menstruations (up to 5 complete menstrual cycles - estimated 150 days)
Cox Menstrual Symptom Severity Scale (CMSS)
The CMSS measures menstrual distress and dysmenorrhea. The CMSS Severity subscale is an 18-item self-reported scale that measures severity of menstrual symptoms, including pain, nausea, emotions, etc. during menstruation. The CMSS will be used in this trial to retrospectively measure the frequency and severity of a participant's menstrual symptoms on the final day of each menstruation.
Time frame: Final day of each menstruation (up to 5 complete menstrual cycles - estimated 150 days)
Numerical Rating Scale (NRS)
The NRS measures menstrual pain daily on a scale of 0 to 10, with zero representing no pain and 10 representing the worst pain imaginable. This is a commonly used scale in studies of dysmenorrhea and other gynecological pain conditions. The NRS will be used in this trial to measure the severity of a participant's menstrual pain on each day of each menstruation.
Time frame: Daily throughout all five menstruations (up to 5 complete menstrual cycles - estimated 150 days)
RAND Short Form-36 (RAND-36)
The RAND-36 is a 36-item patient-reported questionnaire that assesses general quality of life. This questionnaire includes eight variables: physical functioning, social functioning, role limitations due to physical problems, role limitations due to emotional problems, mental health, energy and vitality, pain, and general perception of health. This questionnaire will be completed by the participant at the end of each menstruation.
Time frame: Final day of each menstruation (up to 5 complete menstrual cycles - estimated 150 days)
Menstrual Bleeding Questionnaire (MBQ)
The MBQ measures the impact of heavy menstrual bleeding on health-related quality of life in adult women. The MBQ is a 20-item self-reported scale that evaluates the frequency and severity of menstrual symptoms and their effects on physical, social, and emotional functioning, daily activities, and overall well-being. Responses are captured on Likert-type scales, with higher scores indicating greater symptom burden and functional impairment. The MBQ will be used in this trial to measure the severity of the adult cohort's menstrual pain on the final day of each menstruation.
Time frame: Final day of each menstruation (up to 5 complete menstrual cycles - estimated 150 days)
Adolescent Menstrual Bleeding Questionnaire (aMBQ)
The aMBQ measures HMB-related quality of life in adolescents. The aMBQ is a 19-item self-reported scale that evaluates symptom burden and its effects on school attendance and performance, extracurricular and social activities, physical functioning, and emotional well-being, using Likert-type responses with higher scores indicating greater impact. The aMBQ will be used in this trial to measure the severity of the adolescent cohort's menstrual pain on the final day of each menstruation.
Time frame: Final day of each menstruation (up to 5 complete menstrual cycles - estimated 150 days)
Device Usability Questionnaire
The Device Usability Questionnaire is a 16-item survey that includes both Likert-scale questions (ranging from Strongly Agree to Strongly Disagree) and open-ended free-text responses. It is designed to assess participants' overall satisfaction with the device and to evaluate how easily they were able to operate it using the provided instructions and support materials (Instruction for Use and Quick Start Guide).
Time frame: Final day of Menstruation 3 and Menstruation 5 (estimated 10 days per menstruation)
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Spark Biomedical, Inc.