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1. AcceptedArticle Tricuspid regurgitation and abnormal isthmic flow: prenatal manifestations of
hyperthyroidism
A. Mendez1
, JL. Bigras1
, J. Deladoëy1
, F. Hoberhoffer1
,J. Dery2
, F. Audibert3
, MJ.
Raboisson1
1Department of Paediatrics, Sainte-Justine University Hospital Center, University of
Montreal, Montreal, Quebec, Canada; 2Department of Radiology, Sainte-Justine
University Hospital Center, University of Montreal, Montreal, Quebec, Canada;
3Department of Obstetrics and Gynecology, Sainte-Justine University Hospital Center,
University of Montreal, Montreal, Quebec, Canada
Corresponding author: Marie-Josée Raboisson, MD
Address: Division of Cardiology, CHU Sainte Justine, 3175 Chemin de la Côte Sainte
Catherine, Montréal, QC, Canada, H3T 1C5
e-mail: mjraboisson@gmail.com
Tel: 001 514 345 4931 ext 5403;
Fax: 001 514 345 4896
Short title : fetal heart and hyperthyroidism
Key words
hyperthyroidism, tricuspid regurgitation, fetal cardiomyopathy
Introduction
Fetal thyrotoxicosis is a rare but severe disease.1-2
Few cases of cardiac manifestations
have been reported in fetuses. We present 2 fetuses with moderate to severe tricuspid
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This article has been accepted for publication and undergone full peer review but has not
been through the copyediting, typesetting, pagination and proofreading process, which
may lead to differences between this version and the Version of Record. Please cite this
article as doi: 10.1002/uog.17359

2. AcceptedArticle regurgitation, right ventricular cardiomyopathy and abnormal isthmic flow due to
maternal Graves' disease.
Case report
The first fetus was referred at 30 weeks gestational age for tachycardia at 180
beats/min. The second was referred at 24 weeks GA for cardiomegaly and pericardial
effusion (figure 1). His cardiac rate was normal (150 beats/min). Both fetuses had dilated
and hypertrophied right ventricle, moderate to severe tricuspid regurgitation and
dilatation of the superior vena cava (figure 1). Aortic isthmic flow was abnormal for both
fetuses. The first fetus had a retrograde flow at the end of the systole and no antegrade
flow during mid and end diastole. The second fetus had a retrograde flow at end systole
and during all the diastole (figure 2B-2C)3
. The aortic isthmus was also hypoplastic in the
second fetus. The first mother had been treated previously for Graves´ disease with
radioiodine and propylthiouracile. The fetus was diagnosed with Graves´
hyperthyroidism secondary to circulating maternal thyroid stimulating antibodies. A
thyrotoxic goiter measured at 21mm was diagnosed in the second fetus. The mother
was treated years ago for thyrotoxicosis and was lost to follow up. After 3 weeks of
maternal treatment with methimazole, tricuspid regurgitation and right cardiomyopathy
improved and further echocardiographic studies were normal for the 2 patients.
Discussion
Fetal thyrotoxicosis is mostly secondary to maternal Graves´ disease and results from
trans-placental transfer of maternal thyroid stimulating hormone receptor antibodies
which stimulate the fetal thyroid. Even women with a euthyroid status can keep high
levels of antibodies.4
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3. AcceptedArticle In our 2 patients, thyroid goiter behaves like a low resistance territory :part of left
ventricular flow is directed to the thyroid with lower antegrade flow in the aortic isthmus
and increased retrograde flow coming from the ductus arteriosus and the right ventricle.
Hypoplasia of the aortic isthmus may be secondary to this lower antegrade flow. Thyroid
hyper-vascularisation also causes an increased venous return in the superior vena cava
which is dilated. The right ventricular pre load is also enhanced with right ventricular
overload leading to hypertrophy and dilatation. Tricuspid regurgitation may result from
right ventricular enlargement and remodeling.
Conclusion
Prognosis of moderate or severe tricuspid regurgitation in fetuses is poor. 5
We believe
that, in cases of unexplained tricuspid regurgitation associated with right heart failure
and modification of the aortic isthmic flow, it may be important to consider fetal
hyperthyroidism. Research of cardiovascular and hemodynamic modifications should
probably be part of the screening for fetuses at risk for hyperthyroidism.
DISCLOSURE
None
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4. AcceptedArticle Legen
Figure
transv
(cardi
level o
nds
e 1 :tricuspid
versal view. O
io thoracic ra
of the right at
regurgitatio
On the left, m
tio 67%) with
trium and ve
n and cardiom
moderate tricu
h right chamb
ntricle (arrow
megaly Fetus
uspid regurgit
bers enlargem
ws).
s 24 weeks ge
tation (TR). O
ment and mild
estational age
On the right, c
d pericardial e
e, thoracic
ardiomegaly
effusion at thee
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5. AcceptedArticle
Figure
anteg
fetus
anteg
retrog
e 2 :isthmic b
grade in systo
1, 30 weeks g
grade flow is o
grade flow an
blood flow. 2A
le and diasto
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only seen in e
nd retrograde
A : normal Do
le except for
ge. During sys
early diastole
e flow through
oppler at 25 w
a brief revers
stole, the rev
. 2C : fetus 2,
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weeks gestati
se flow at the
verse flow is in
24 weeks ge
e.
onal age. The
e end of the s
ncreased and
estational age
e flow is
systole. 2B :
d the
e, end systolicc
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6. AcceptedArticle
REFERENCES
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4. Batra CM. Fetal and neonatal thyrotoxicosis. Indian J Endocrinol Metab 2013; 17 (Suppl
1): S50‐4.
5. Lasa JJ, Tian ZY, Guo R, Rychik J.Perinatal course of Ebstein's anomaly and tricuspid valve
dysplasia in the fetus.Prenat Diagn. 2012 Mar;32(3):245‐51.
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