A cycle study is a longitudinal diary: bleeding days, symptoms, ovulation test results and, often, a wearable temperature signal, tracked across several cycles per participant. Capture runs the daily phone diary, the clinic visits and the consent in one study. Build and test it free, no credit card.
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Daily cycle diary on the phone (demo)
Participant 004-0031 · Cycle 2, day 14
Today
Bleeding
BLEEDUrinary LH test
LHTESTCramps
CRAMPSMood
MOODCycle day
CYCDAYCounted from the logged first day of bleeding
14What a cycle tracking study needs from its software
The study data
Cycle research spans very different questions: how well a wearable temperature signal detects the post-ovulation shift, how symptoms vary across the cycle, how a supplement or contraceptive affects cycle regularity, and how conditions such as endometriosis or polycystic ovary syndrome show up in daily life. The common ingredients are the same. A participant logs bleeding days, symptoms and sometimes basal body temperature or an ovulation test each day. Published method studies often use the urinary luteinising hormone (LH) surge as the ovulation reference, and compare it against morning basal temperature or a sleeping wrist or ring skin temperature, usually over a few cycles per participant. Menstruation diaries then confirm the cycle boundaries.
The data-quality risk is gaps. A missed diary day in a daily design is a missing observation, and missing days cluster around the very events the study cares about, such as the days around ovulation or the first days of bleeding. Capture lets you set reminders and a completion window on a daily task, and a compliance view shows which participants are slipping so the team can reach them before a cycle is lost. See ePRO compliance reminders by SMS and email and digital patient diary for clinical studies.
The cycle clock is the second risk. Cycle day is anchored to the first day of bleeding, and participants may log it late or revise it. Because Capture keeps a field-level audit trail with the old value, new value and reason for any change, a corrected bleeding start is visible rather than silently overwriting the cycle structure. Design the diary so bleeding is a required daily field, and decide in the data management plan how a cycle is defined, for example the days between two first-bleeding days, so analysts build it the same way.
Capture connects wearables through native OAuth: the study team enables a device per study and can mark it required, the participant connects their own account through the vendor sign-in from a link in the study, and data then syncs automatically, with last-sync time, a Sync now action and disconnect. An Oura-style ring is the device established in the product; which other devices are configured is checked per study before you promise a design. The full pattern is in EDC for wearable device studies and best EDC for wearable data, and consent for sharing device data is covered by the wearable data sharing consent template. Urinary LH tests are participant-read, so the diary records the result as a choice and, if your protocol requires, a photo reference kept in the system it names. Hormone assays from the clinic belong on a laboratory form.
Protocol to build
| Protocol element | What the data looks like | Where it lives in Capture |
|---|---|---|
| Eligibility | Cycle regularity, contraception, age, conditions | Eligibility screening template with edit checks |
| Consent | Participant signature, sensitive-data and device-sharing consent | eConsent; wearable data sharing consent template |
| Daily bleeding and symptoms | Choice and scale answers each day | Daily phone diary with reminders; see pain diary and mood tracker for layouts |
| Ovulation test results | Negative or positive each day of the window | Choice field in the daily diary |
| Temperature signal | Continuous or nightly device values | Native OAuth wearable sync where the device is configured |
| Sleep | Sleep quality across the cycle | Sleep diary |
| Clinic visits | Blood, scan, anthropometrics at timed visits | Vital signs and lab results templates |
| Adverse events | Product- or device-related events | Adverse event form |
Scale and questionnaire wording is yours to supply. Licensed instruments stay with your study documents; Capture does not supply or verify instrument licences.
Create the daily task, add reminders, enter sample cycles and watch the compliance view. Free sandbox, no credit card.
Privacy and consent
Cycle data is among the most sensitive health information a study can hold, and participants are right to ask where it lives and who can see it. Capture hosts data in the EU (Frankfurt) or the USA (N. Virginia) so residency can match your ethics approval; applies AES-256 encryption at rest and TLS in transit; and segregates PII, so site coordinators see participant names while researchers work with coded IDs, enforced by row-level security at the database layer. What those terms do and do not mean is set out in GDPR-compliant clinical trial software and HIPAA-compliant clinical trial software.
Consent should be specific about what is collected and shared: daily diary answers, test results, wearable data and any clinic samples. Capture eConsent supports an on-screen participant signature with an email one-time code and investigator countersignature, and each signature is linked by hash to the exact document content. Your ethics committee approves the wording; the wearable data sharing consent template is a layout to start from. Participants can also disconnect a device themselves, which should be explained in the consent text.
Not every cycle study is a trial. Observational and prospective designs fit the same tools, and the sister pages are EDC for endometriosis, PCOS and fertility trials for clinical programmes and ecological momentary assessment software for repeated in-the-moment sampling. Where a published method claim matters, use the primary literature for the study, not marketing claims, and remember that a consumer cycle-prediction app is a different thing from a research instrument with an audit trail and consent.
Build sequence
A practical order of work for a research team.
Write down how a cycle starts and ends, how many cycles each participant contributes and what counts as a usable cycle.
Upload the protocol or describe the form and let the AI draft questions for you to review. Nothing is saved until a person reviews it.
Set the daily diary with reminders and a completion window, plus any weekly or cycle-phase questionnaires.
Add timed visits for samples and measurements, and enable the wearable per study if the protocol uses one.
Enter sample data for every day of a cycle, trigger the checks and read the audit trail.
Approved forms lock for live use. Real participants start the paid live phase.
Before first participant
How cycle start, end and usable cycles are defined for analysis.
Wording for sensitive data and device sharing reviewed by the ethics committee.
Time of day, completion window and what staff do when diaries lapse.
Which wearable is used and that its sync is configured for the study.
CSV or Excel with the data dictionary opened in the statistics package.
Yes. A daily task opens from a secure link in the phone browser, with reminders and a completion window you control. There is no app to install.
Capture supports native OAuth wearable sync, where the participant connects their own account and data syncs automatically. An Oura-style ring is the established device; confirm any other device for your study before relying on it.
Cycle day is counted from the logged first day of bleeding. Capture records the dates and the audit trail; your data management plan should state how a cycle is bounded so analysis is consistent.
Data is hosted in the EU (Frankfurt) or USA (N. Virginia), encrypted at rest and in transit, with PII segregation and role-based access. See the security page for details.
Yes. Timed visits use eCRF forms, such as vital signs and laboratory results, in the same study as the daily diary.
The sandbox is free with every feature, no credit card and no time limit. You pay only once you go live with real participants. Pricing is not published on the site, so ask for terms for your study via the demo page or the pricing page.
Keep exploring
EDC for wearable device studies
Native OAuth sync pattern.
EDC for endometriosis, PCOS and fertility trials
Clinical programmes.
Ecological momentary assessment software
Repeated in-the-moment sampling.
Wearable data sharing consent
Consent layout for device data.
Security
Hosting, encryption and access controls.
ePRO software
Daily diaries and questionnaires.
Free sandbox with every feature. No credit card, and you pay only when you go live.