NCT04474223 · NYU Langone Health
Surveillance and Treatment to Prevent Fetal Atrioventricular Block Likely to Occur Quickly (STOP BLOQ)
What this study is about
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.
View original scientific description
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.
Interventions
DRUG
Dexamethasone
In mother in whom 2° AVB or AV interval \>170 ms has been diagnosed in the fetus: Dexamethasone 8 mg po/day for 10 days. Then dexamethasone 4 mg po/ day through 28 weeks 6 days gestational age (GA); then 3 mg/day from 29 wks 0 days to 29 wks 6 days GA; then 2 mg/day until delivery
DRUG
IVIG
In a mother in whom 2° AVB has been diagnosed in the fetus: One dose of IVIG \[1g/kg of maternal weight (max dose 70 g)\] at diagnosis of 2° AVB (within 12 hours of detection by mother via home monitoring and within 6 hours of confirmation by echocardiogram). A fetal AV interval \> 170 ms will not be treated with maternal IVIG, only dexamethasone.
Primary outcome measures
Percentage of 2° AVB subjects with NR (1:1 AV conduction) at birth
Time frame: up to 25 weeks post-enrollment
The presence of NR (normal rhythm) will be determined by electrocardiogram (ECG)
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Provision of signed and dated informed consent form 2. Stated willingness to comply with all study procedures and availability for the duration of the study 3. Be \<18 weeks pregnant at the time of enrollment 4. Titer of anti-Ro 52 or 60 antibodies ≥1,000 EU 5. Any positive titer of anti-Ro if a history of a previously affected child 6. Ability to take oral medication and be willing to adhere to the dexamethasone and IVIG protocols. 7. Ability to perform Doppler fetal heart rate and rhythm monitoring in the ambulatory setting, 8. Ability to send an audiotext message by cell phone therefore the participant will be informed that they need a phone with texting capabilities. Located within 6 hours drive of the participating pediatric cardiology site 9. Be ≥18 years of age
Exclusion criteria
- Multi-fetal pregnancy 2. Known allergic reactions to components of IVIG, or dexamethasone or maternal IgA deficiency 3. Fetal conduction system disease already present in t
Where
- Phoenix, Arizona
- Los Angeles, California
- Palo Alto, California
- San Francisco, California
- Aurora, Colorado
- New Haven, Connecticut
- Washington D.C., District of Columbia
- Lexington, Kentucky
- Louisville, Kentucky
- Ann Arbor, Michigan
- Minneapolis, Minnesota
- Rio Rancho, New Mexico
And 8 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
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Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
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Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Apr 6, 2026 · Source of record for eligibility and locations