Home Monitoring for Fetal Heart Rhythm During Anti-Ro Pregnancies

Area of Science:

• Maternal-fetal medicine
• Cardiology
• Immunology

Background:

• Fetal atrioventricular block (AVB) affects 2-4% of anti-Ro antibody-positive pregnancies, often developing rapidly (<24 hours).
• Standard surveillance methods rarely detect AVB early enough for effective intervention.

Purpose of the Study:

• To evaluate the effectiveness of twice-daily home fetal heart rate and rhythm monitoring (FHRM) combined with surveillance echocardiography in anti-Ro pregnancies.
• To determine if FHRM can detect AVB early enough for timely treatment.

Main Methods:

• A prospective observational study involving 315 anti-Ro pregnant women across 16 international centers.
• Participants performed twice-daily home FHRM and weekly/biweekly surveillance fetal echocardiograms between 18-26 weeks gestation.
• Diagnostic echocardiograms were performed for abnormal FHRM; cardiac function and intervals were assessed.

Main Results:

• 87% of mothers completed the monitoring protocol, with 1,752 fetal echocardiograms generated.
• Abnormal FHRM was detected in 6.7% of mothers, leading to diagnosis of AVB in 3 fetuses.
• Treatment within 12 hours of abnormal FHRM in second-degree AVB cases restored sinus rhythm; no AVB was missed by home FHRM.

Conclusions:

• Home FHRM effectively identifies the rapid progression from normal rhythm to AVB in anti-Ro pregnancies.
• This monitoring strategy defines a critical time window for successful therapeutic intervention.