Surveillance and Treatment to Prevent Fetal Atrioventricular Block Likely to Occur Quickly (STOP BLOQ)
Public ClinicalTrials.gov record NCT04474223. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.
Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.
Brief summary
Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.
Fetal complete (i.e., third degree, 3°) atrioventricular block (AVB), identified in the 2nd trimester of pregnancy in an otherwise normally developing heart, is almost universally associated with maternal anti-Ro autoantibodies and results in death in a fifth of cases. To date treatment of 3° AVB has been ineffective in restoring normal rhythm (NR) which may be because current surveillance is limited to once- weekly fetal echocardiograms. It is hypothesized that there may be a vital transition period of several hours in which incomplete block (2° AVB) may be successfully treated avoiding fully advanced irreversible 3° AVB. To optimize the likelihood of timely detection of the transition period this study comprises three steps: 1) to risk stratify for high titer anti-Ro antibodies, which are necessary but not sufficient to develop fetal AVB; 2) to empower mothers to identify 2° AVB by using fetal heart rate and rhythm monitoring (FHRM) at home, and 3) to rapidly treat mothers who detect an abnormality by monitoring with an urgent echocardiogram that confirms 2° AVB with the hope of reversing 2° AVB before it becomes permanent (3° AVB). In addition, it will be determined if FHRM reduces the need for weekly echoes. Although mothers with low titer anti-Ro will not be continued in Step 2 and therefore not followed by FHRM, birth ECGs will be collected to confirm that low titer antibodies do not confer risk. It is anticipated that this study will provide an evidenced based surveillance strategy for those mothers at high risk of having a child with 3° AVB.
Study identification
- NCT ID
- NCT04474223
- Recruitment status
- Active, not recruiting
- Study type
- Interventional
- Phase
- Phase 3
- Enrollment
- 1,300 participants
Conditions and interventions
Conditions
Eligibility (public fields only)
- Age range
- 18 Years and older
- Sex
- Female
- Healthy volunteers
- Healthy volunteers not accepted
This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.
Study timeline
- Start date
- Aug 1, 2020 (Actual)
- Primary completion
- Dec 31, 2028 (Estimated)
- Completion
- Jun 30, 2029 (Estimated)
- Last update posted
- Aug 25, 2026
2020 – 2029
United States locations
- U.S. sites
- 23
- U.S. states
- 17
- U.S. cities
- 20
| Facility | City | State | ZIP | Site status |
|---|---|---|---|---|
| Phoenix Children's Hospital/Dignity Health | Phoenix | Arizona | 85016 | — |
| University of California - Los Angeles (UCLA) | Los Angeles | California | 90095 | — |
| Stanford University | Palo Alto | California | 94305 | — |
| University of California-San Francisco | San Francisco | California | 94143 | — |
| University of Colorado, Denver (UCD) | Aurora | Colorado | 80204 | — |
| Yale University School of Medicine | New Haven | Connecticut | 06510 | — |
| Children's National Medical Center/George Washington University | Washington D.C. | District of Columbia | 20010 | — |
| University of Kentucky / Kentucky Children's Hospital | Lexington | Kentucky | 40536 | — |
| University of Louisville / Norton Children's Hospital | Louisville | Kentucky | 40202 | — |
| University of Michigan / C. S. Mott Children's Hospital | Ann Arbor | Michigan | 48109 | — |
| Children's Hospital of Minnesota | Minneapolis | Minnesota | 55404 | — |
| Perinatal Associates of New Mexico | Rio Rancho | New Mexico | 87124 | — |
| NYU Langone Health | New York | New York | 10016 | — |
| Mount Sinai | New York | New York | 10029 | — |
| Columbia University Medical Center | New York | New York | 10032 | — |
| UH Rainbow Babies / Children's Hospital | Cleveland | Ohio | 44106 | — |
| Cleveland Clinic Lerner College of Medicine | Cleveland | Ohio | 44195 | — |
| Vanderbilt University Medical Center | Nashville | Tennessee | 37232 | — |
| Baylor College of Medicine | Houston | Texas | 77030 | — |
| University of Utah Health | Salt Lake City | Utah | 84102 | — |
| University of Vermont Children's Hospital | Burlington | Vermont | 05401 | — |
| Eastern Virginia Medical School (EVMS) | Norfolk | Virginia | 23507 | — |
| Seattle Children's Hospital | Seattle | Washington | 98105 | — |
Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.
Non-U.S. locations
This page focuses on the U.S. directory. The official record also lists 1 non-U.S. site.
About this trial record page
- What this page shows
- Public field values for ClinicalTrials.gov record NCT04474223, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
- What this page does not do
- No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
- Where the data comes from
- Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
- Last refresh
- Last update posted Aug 25, 2026 · Synced Oct 26, 2026
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Open the official record
The complete public registry record, listed eligibility criteria, and available contact information for NCT04474223 live on ClinicalTrials.gov.