This document summarizes a study examining heart defects in fetuses with Turner's syndrome. The study found that among 53 fetuses with a 45X karyotype: - A cardiac abnormality was detected in 62% of fetuses, much higher than rates reported postnatally. - The most common defects were coarctation of the aorta (45% of fetuses) and hypoplastic left heart syndrome (13% of fetuses). - Termination of pregnancy occurred in 85% of fetuses, while spontaneous fetal loss occurred in 6 cases. Two fetuses with a mosaic karyotype survived to birth.

1. Ultrasound Obstet Gynecol 2003; 22: 264–267
Published online 9 June 2003 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/uog.151
Turner’s syndrome in fetal life
E. SURERUS, I. C. HUGGON and L. D. ALLAN
Fetal Cardiology Unit, Harris Birthright Research Centre for Fetal Medicine, King’s College, London, UK
KEYWORDS: cardiac defects; echocardiography; fetus; first trimester; karyotype; Turner’s syndrome
ABSTRACT
Objective To compare the incidence and type of heart
disease found in association with 45X karyotype in fetal
life with postnatal life and to examine the outcome after
fetal diagnosis.
Methods Fifty-three fetuses with a 45X karyotype were
examined echocardiographically over a 4-year period
between 1999 and 2002. Of these, 47 were referred
because of increased nuchal translucency (NT).
Results A cardiac abnormality was detected in 33/53
(62.2%) fetuses. The most common diagnosis was
coarctation of the aorta in 24/53 (45.3%) fetuses,
followed by the hypoplastic left heart syndrome (HLHS)
in 7/53 (13.2%) fetuses. The mean NT was significantly
higher in fetuses with a heart defect than in those with
normal echocardiography. Termination of pregnancy was
carried out in 45/53 (84.9%) fetuses and intrauterine
death occurred in six cases. Two of four fetuses with a
mosaic karyotype are currently alive.
Conclusion Turner’s syndrome is associated with a
higher incidence of heart defects detected prenatally
when compared to postnatal reports. The commonest
associated heart defects detected prenatally are HLHS and
coarctation of the aorta, in contrast to postnatal life where
a bicuspid aortic valve is the most common diagnosis. The
typical intrauterine presentation of Turner’s syndrome
with a markedly increased NT or with hydrops and
with a typical 45X karyotype has an extremely poor
prognosis for intrauterine survival. Copyright  2003
ISUOG. Published by John Wiley & Sons, Ltd.
INTRODUCTION
Turner’s syndrome is a well-recognized clinical entity
in children and adults, which includes cardiovascular
abnormalities, webbing of the neck, short stature and
ovarian dysfunction. It is characteristically associated
with monosomy of the X chromosome on karyotyping,
but nearly half of the cases recognized postnatally have
other X chromosome anomalies, such as mosaicism, ring
formation or deletions1,2
. Structural heart disease is a
feature of Turner’s syndrome, occurring in 15–30% of
those presenting in postnatal life2–5. The most frequent
cardiac abnormalities are a bicuspid aortic valve, which
occurs in 14–19% of cases, or coarctation of the aorta in
around 4–10% of cases. More severe left heart disease,
including the hypoplastic left heart syndrome (HLHS),
is also reported6. The prognosis for girls presenting
with Turner’s syndrome beyond the neonatal period is
generally good with appropriate treatment. In particular,
intellectual development is usually normal. The endocrine
deficiencies can usually be overcome by supplementation7
.
In fetal life there is a typical group of obstetric
ultrasound findings associated with Turner’s syndrome,
including cystic hygroma and fetal hydrops, which are
most commonly found up to 21 weeks’ gestation8–10.
In addition, a 45X karyotype is commonly identified
at chorionic villus sampling (CVS) after the detection
of increased nuchal translucency (NT) at the 11–14-
week scan. Usually, the NT in Turner’s syndrome is
markedly increased above the normal range11, and may
be associated with additional features of fluid retention.
The prognosis following presentation in this fashion
appears to be very much worse than that associated
with postnatal presentation of Turner’s syndrome. There
is a known high rate of spontaneous fetal loss in utero,
with a suggested incidence of at least 80% of fetuses with
Turner’s syndrome dying between 10 weeks’ gestation
and term12, with some authors reporting a mortality of
99% from the first trimester8
. Presentation with hydrops
may itself predict fetal loss10,13
.
The objective of this study was to compare the incidence
and type of heart disease found in association with 45X
karyotype in fetal life with that reported in postnatal life
and to document the outcome after fetal diagnosis.
Correspondence to: Prof. L. D. Allan, Harris Birthright Research Centre, 3rd Floor Jubilee Wing, King’s College Hospital, Denmark Hill,
London SE5 9RS, UK (e-mail: la48@columbia.edu)
Accepted: 27 March 2003
Copyright  2003 ISUOG. Published by John Wiley & Sons, Ltd. ORIGINAL PAPER

2. Fetal Turner’s syndrome 265
METHODS
A retrospective search of our database between February
1999 and July 2002 identified 78 cases of Turner’s
syndrome after karyotyping at the Harris Birthright
Research Centre for Fetal Medicine. Of these, 61 cases
had been examined echocardiographically by abdominal
ultrasound. In eight cases the echocardiographic images
were not diagnostic, leaving 53 cases to be analyzed in
this study. Fifty-two patients had fetal echocardiography
prior to invasive testing for fetal karyotype and one after
a 45X karyotype had been detected. The ultrasound
examination was performed using an Acuson Aspen
(Acuson, Mountain View, CA, USA) with a C7 7-MHz
probe. Of these 53 cases, 47 were referred because of
increased NT > 4 mm, which is our arbitrary cut-off for
early specialized fetal cardiac evaluation. The gestational
age of this group ranged between 11 and 14 (mean, 12)
weeks. A further five cases were referred because of fetal
hydrops between 15 and 20 (mean, 18) weeks, and in
the remaining case echocardiography was performed in
a fetus in which the NT was 1.5 mm but a mosaic 45X
karyotype was detected at CVS for a previous history of
trisomy 18.
RESULTS
The diagnosis of cardiac normality or abnormality was
made at the first visit in 51 fetuses. In two fetuses, diag-
nostic images were not achieved at 11 and 12 weeks but
were obtained at 13 and 15 weeks, respectively. Of the 53
cases, 49 were 45X karyotype and four had mosaicism for
45X. The gestational age at diagnosis was < 14 weeks in
47/53 cases. A cardiac abnormality was detected in 33/53
(62.3%) cases (Figure 1). The most common diagnosis
was disproportion between the two ventricles and between
the aorta and pulmonary trunk suggestive of coarctation
of the aorta 24/53 (45.3%) cases, followed by the HLHS
in 7/53 (13.2%) cases (Figures 2 and 3). In addition, there
was one case of an atrioventricular septal defect (AVSD)
and one of isolated tricuspid regurgitation. Of the four
mosaic karyotypes, all had a normal heart scan.
Of the group of 53 pregnancies, termination of preg-
nancy (TOP) took place in 45 (84.9%) pregnancies, and
spontaneous intrauterine death occurred in six cases at
gestations ranging between 16 and 33 weeks (Table 1).
In five of those six patients, later echocardiography con-
firmed the earlier findings. Of those four cases with a
mosaic karyotype, two patients chose pregnancy inter-
ruption without further testing, and two continued the
pregnancy without amniocentesis, which was offered.
Both newborns are alive and well, with normal hearts
as predicted. Of these, one had a normal postnatal
karyotype and the remaining case showed no obvious
signs of Turner’s syndrome at birth but postnatal kary-
otyping revealed 45X in all cells analyzed. Postmortem
Turner’s syndrome
n = 53
Normal echocardiography
n = 20 (37.7%)
Abnormal echocardiography
n = 33 (62.3%)
Coarctation
n = 24 (45.3%)
HLHS
n = 7 (13.2%)
Other
n = 2 (3.7%)
Figure 1 Echocardiographic findings in the fetuses with Turner
syndrome. HLHS, hypoplastic left heart syndrome; Other,
atrioventricular septal defect and tricuspid regurgitation.
RV
LV
LV
RV
S
S
Figure 2 (a) Normal four-chamber view of the heart at 12 weeks and (b) hypoplastic left heart at 12 weeks in a four-chamber view. There
was no flow into the left ventricle on color flow mapping and reverse flow in the arch. LV, left ventricle; RV, right ventricle; S, spine.
Copyright  2003 ISUOG. Published by John Wiley & Sons, Ltd. Ultrasound Obstet Gynecol 2003; 22: 264–267.

3. 266 Surerus et al.
LV
RV
S
*
Figure 3 Ventricular disproportion at 16 weeks suggestive of
coarctation of the aorta. *, pleural effusion; LV, left ventricle;
RV, right ventricle; S, spine.
Table 1 Outcome of pregnancy according to fetal karyotype
45X karyotype Mosaic karyotype Total
TOP 43 2 45
IUD 6 0 6
LB 0 2 2
Total 49 4 53
IUD, intrauterine death; LB, live birth; TOP, termination of
pregnancy.
examination confirmed the echocardiographic findings in
five cases, two of which were predicted to have coarcta-
tion, two with HLHS and one with an AVSD.
The mean NT in the group of 47 fetuses with increased
NT (over the 95th centile for the crown–rump length) was
9.8 (range, 4.1–17.1) mm. The mean NT was significantly
higher in those cases with heart disease detected prenatally
(10.9 mm), than in those without cardiac abnormalities
(8.0 mm) (F statistic = 24.04, P = 0.0001). In addition,
the NT was higher in those cases with monosomy
X than in those with mosaicism (10.0 vs. 4.8 mm)
(F statistic = 13.4, P = 0.000671). Student’s t-test was
used in the statistical analysis.
DISCUSSION
The relatively benign course for a case of Turner’s
syndrome detected postnatally appears to be in sharp
contrast to the prognosis of those cases observed in fetal
life7,14
. The group of Turner’s syndrome detected by
increased NT between 11 and 14 weeks or with hydrops
at later gestation are known to have a high rate of
spontaneous fetal loss10,13
and this was confirmed in
our series. Only one of the cases in our series was found
at invasive testing by chance because of a previous history
of trisomy 18. In contrast, Saenger states in his review14
that most prenatal diagnosis of Turner’s syndrome occurs
by chance after routine amniocentesis for maternal age.
Such cases may have quite a different prognosis from the
group seen by us at a referral center with increased NT
or hydrops. Thus, our findings may not be applicable to
cases found in different clinical settings.
In our study, a higher incidence of congenital heart
defects was found compared to those cases identified
postnatally (62% vs. 20%). Coarctation of the aorta
was found in 45% of cases and the HLHS in 13%
prenatally, in contrast to 4–7% and 1–2%, respectively,
reported postnatally15,16
. A limitation of our study is
the small number of postmortem examinations after
TOP or miscarriage to confirm the prenatal diagnosis
of heart defects, but in 10 cases with either postmortem
or later echocardiography, the findings were confirmed.
The low rate of postmortem examination was because
most patients are referred to us from other hospitals for
CVS with the TOP taking place locally after the result
has been obtained. In addition, as most terminations
took place prior to 14 weeks the mode of termination
was surgical, which did not provide an intact fetus for
examination. In a series of four fetuses seen prior to
14 weeks’ gestation with increased NT and Turner’s
syndrome, reported by Haak et al., the HLHS was
found in 3/4 cases17
. Although their numbers are small,
fetal echocardiography in the first trimester successfully
identified this abnormality, which they confirmed at
postmortem examination. Gembruch et al. described a
hypoplastic aortic arch and hypoplastic left ventricle as the
commonest cardiac anomalies associated with Turner’s
syndrome in their prenatal series of five cases18
.
Isolated bicuspid aortic valve constitutes the majority
(12–34%) of heart defects identified in postnatal
life3,5,15,19 but this lesion cannot generally be detected
during prenatal ultrasound and was not seen in our series.
The X ring karyotype was related to a prevalence of
33.3% of cardiac defects in postnatal life by Prandstraller
et al. but the most common abnormality found in
association with this karyotype pattern was a bicuspid
aortic valve3,15,20
.
There is also a difference in the karyotype found
prenatally from that found postnatally. In our series,
almost all cases were of monosomy X fetuses (92.5%),
with only a small proportion of mosaics (7.5%), and
no cases of more minor X chromosome defects were
seen. It is, of course, possible that some of the cases of
mosaicism were not truly fetal mosaicism but confined
to the placenta. In the two continuing pregnancies with
mosaicism the parents decided against amniocentesis. In
one a postnatal karyotype proved normal and the other
was a true case of 45X. Similar to our findings, Monney
et al. report rates of 84.5% and 13.5% for 45X and
mosaic karyotype, respectively, in their prenatal series8
.
In contrast, in postnatal series, Gotzsche et al. reported
58% 45X karyotypes, 35% mosaics and 7% of structural
abnormalities and Douchin et al. reported 50% 45X
and 50% mosaics or structural abnormalities2,21
. This
Copyright  2003 ISUOG. Published by John Wiley & Sons, Ltd. Ultrasound Obstet Gynecol 2003; 22: 264–267.

4. Fetal Turner’s syndrome 267
suggests that most of the children with mosaicism or
more minor X anomalies, who comprise about half the
postnatal series, may appear normal at the ultrasound
examination in intrauterine life and also that intrauterine
lethality for 45X karyotype is higher than in mosaics.
Gravholt et al. observed in their series of 100 fetuses that
the probability of a mosaic karyotype fetus to reach term
was significantly higher than a 45X fetus surviving12
. In
our series, none of the six fetuses with a 45X karyotype,
where there was expectant management, survived to
term, although there was a wide range in the timing of
spontaneous loss (16–33 weeks). Conversely, two mosaic
pregnancies continued and delivered live births. It is of
interest that of our four mosaics, although three were
detected for increased NT, the increase in measurement
was more modest in these cases than in the group with
monosomy X at 4.3, 6.7 and 6.8 mm, respectively.
In postnatal series, the nature of the karyotype is
also strongly associated with the severity of the cardiac
abnormality identified. Fetuses with 45X karyotype have
been reported to be more likely to have a heart defect,
and to have a more severe form of cardiac disease,
such as coarctation of the aorta, than the mosaics
(29–30% vs. 16.6–24.3%)3,15
. Structural abnormalities
in the X chromosome are generally associated with
milder abnormalities such as bicuspid aortic valve and
cardiac dysfunction3
. Gotzsche et al. report a series of 179
patients where there was a cardiovascular malformation
in 38% with 45X karyotypes as against 11% with a
mosaic karyotype. None of their patients with structural
abnormalities of the X chromosome had cardiovascular
malformations2
.
In conclusion, there is a higher incidence of congenital
heart disease diagnosed in cases of Turner’s syndrome
where prenatal identification occurs as a result of
abnormal ultrasound findings. These fetuses usually
present with more severe forms of heart defects and this is
associated with a specific fetal karyotype of monosomy X.
In addition, the typical intrauterine presentation of
Turner’s syndrome with a markedly increased NT or with
hydrops has an extremely poor prognosis for survival.
ACKNOWLEDGMENT
This study was supported by a grant from The Fetal
Medicine Foundation (Registered Charity 1037116).
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