Flo Digital Contraceptive Study

NCT07630064 | Recruiting DMC FDA Device

• 1 other identifier: LH074
• Study Type: interventional
• Target: 3,800
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to learn if the Flo Digital Contraceptive (FDC) app can effectively prevent unintended pregnancy in women aged 18 years and older residing in the United States. The main questions it aims to answer are: What is the rate of unintended pregnancy in women aged 18-35 years using FDC as their sole method of contraception under typical-use conditions, measured using the Pearl Index? What is the cumulative probability of unintended pregnancy over 13 menstrual cycles for all participants, including those with regular and irregular cycles? Participants will: Use the Flo Digital Contraceptive app in 'prevent pregnancy' mode as their primary method of contraception for up to 13 menstrual cycles or 18 months, whichever comes first Wear an Apple Watch (Series 8 or later, or Ultra) while sleeping to collect nightly wrist temperature data, which the app uses to detect ovulation Log menstrual cycles, sexual activity, and any use of emergency contraception directly in the Flo app Complete monthly electronic surveys (ePROs) administered by the study team covering pregnancy status, adherence, safety, and experience Complete a baseline demographic survey at enrollment and an exit survey at the end of participation

Conditions

Contraception Use

Outcome Measures

Primary Outcomes (1)

• Typical-Use Pearl Index in Women Aged 18-35 Years with Regular Menstrual Cycles

  The Pearl Index (PI) is calculated as the number of unintended pregnancies per 100 woman-years of FDC exposure, assessed under typical-use conditions in women aged 18-35 years with regular menstrual cycles (21-35 days). An unintended pregnancy is defined as a documented positive pregnancy test occurring during active FDC use. Exposure time is calculated from the date of first FDC use (device activation) until confirmed pregnancy, intentional discontinuation, loss to follow-up, completion of 13 cycles, or study end, whichever occurs first. The PI is calculated with 95% exact Poisson confidence intervals. Effectiveness is concluded if the upper bound of the two-sided 95% CI is below the pre-specified clinically acceptable threshold of 10 pregnancies per 100 woman-years.

  Up to 13 menstrual cycles or 18 months from FDC activation, whichever occurs first.

Secondary Outcomes (7)

• Typical-Use Cumulative Pregnancy Probability Over 13 Cycles in Women Aged 18-35 Years (All Cycles)

  Up to 13 menstrual cycles or 18 months from FDC activation, whichever occurs first.

• Perfect-Use Pearl Index in Women Aged 18-35 Years with Regular Menstrual Cycles

  Up to 13 menstrual cycles or 18 months from FDC activation, whichever occurs first.

• Perfect-Use Cumulative Pregnancy Probability Over 13 Cycles in Women Aged 18-35 Years (All Cycles)

  Up to 13 menstrual cycles or 18 months from FDC activation, whichever occurs first.

• Typical-Use Pearl Index in the Full Intended-Use Population (Aged 18+) with Regular Menstrual Cycles

  Up to 13 menstrual cycles or 18 months from FDC activation, whichever occurs first.

• Typical-Use Cumulative Pregnancy Probability Over 13 Cycles in the Full Intended-Use Population (Aged 18+, All Cycles)

  Up to 13 menstrual cycles or 18 months from FDC activation, whichever occurs first.

Study Arms (1)

Single Arm Device Intervention

EXPERIMENTAL

Users exposed to the Flo Digital Contraceptive

Device: Flo Digital Contraceptive

Interventions

Flo Digital Contraceptive DEVICE

The Flo Digital Contraceptive (FDC) is a fertility awareness-based Software as a Medical Device (SaMD) integrated within the Flo Period \& Cycles Tracker app (iOS) in 'prevent pregnancy' mode. The FDC uses a proprietary machine-learning algorithm to classify each day of the user's menstrual cycle as either 'Not fertile' (unprotected intercourse permitted) or 'Use protection' (abstinence or barrier contraception required). Classifications are generated dynamically using menstrual cycle history and overnight wrist-skin temperature measured via Apple Watch (Series 8 or later, or Ultra), synchronized daily through Apple Health, with optional urinary LH test results as a supplementary input. Participants use FDC as their sole method of contraception for up to 13 menstrual cycles or 18 months from device activation, whichever occurs first.

Also known as: FDC

Single Arm Device Intervention

Eligibility Criteria

• Age: 18 Years+
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults with female reproductive organs aged ≥18 years
• Reside in the United States of America
• Have menstrual frequency (i.e., interval between first day of bleeding each cycle) between 16-90 days
• Sexually active, having vaginal sex with male partner(s) without known fertility problems AND where neither partner has a known, or is at high risk of, sexually transmitted infections (STIs).
• Desiring contraception, i.e., planning to prevent pregnancy and not currently trying or planning to conceive for at least 12 months, and up to 18 months. from enrollment
• Willing and able to use FDC as advised, including ability to:
• (1) Abstain from penile-vaginal intercourse on days indicated as "Use protection" OR
• (2) Use barrier methods (such as condoms) for penile-vaginal intercourse on days indicated as "Use protection"
• Possession of an iOS mobile device (version 16 or higher) with internet connectivity
• Sufficient English language proficiency and knowledge of English language required for correct use of the intervention and mobile device
• Willing to wear a functional Apple Watch capable of sensing wrist-skin temperature (Series 8 or later, Ultra) while sleeping, with it connected and sharing temperature data to the Flo application
• No known pregnancy at the time of enrollment
• Willing and able to provide valid consent

You may not qualify if:

• Current use of any contraceptive medication, implant or technique, including but not limited to:
• Oral contraceptive pills
• Hormonal implants, injections, vaginal rings or transdermal patches
• Intrauterine devices (copper and/or levonorgestrel)
• Surgical sterilization (tubal ligation, salpingectomy, intrafallopian tube coils)
• ≤12 weeks postpartum (second or third trimester pregnancy)\*
• \*Includes terminations of any pregnancy \>14 weeks OR have given birth \>12 weeks postpartum without return of at least one menses
• Postabortion (first trimester miscarriage, ectopic, termination) who have:
• History of cycles outside the 21-35 day range, OR
• Not had return of at least one menses following the abortion
• Currently lactating (breastfeeding, pumping or otherwise), regardless of interval since last pregnancy
• Had fewer than 9 menstrual cycles in the past 12 months
• Have received medical advice from a healthcare provider that pregnancy is medically contraindicated, irrespective of whether this is due to a medical condition or risk, or due to medication being taken, or other reason.
• Participants must be willing to NOT use condoms for penile-vaginal intercourse. Those who are unable or unwilling to restrict use of condoms for penile-vaginal intercourse for any reason, including but not limited to compromising health and/or safety of self or others will be excluded
• Note: Use of barrier contraceptive for sexual encounters that could not result in pregnancy, such as oral or anal sex, is not restricted

Sponsors & Collaborators

• Flo Health Inc.: lead
• Lindus Health: collaborator

Study Sites (1)

Lindus Health

Boston, Massachusetts, 02111, United States

RECRUITING

Study Officials

• Shannon Maclaughlan-David, MD, MS

  Lindus Health

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Collin Anderson, MPH

CONTACT

833-930-8220; collin.anderson@lindushealth.com

Keith Boland

CONTACT

(833) 930-8220

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 1, 2026
• First Posted: June 5, 2026
• Study Start: April 22, 2026
• Primary Completion (Estimated): January 10, 2028
• Study Completion (Estimated): January 10, 2028
• Last Updated: June 5, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)