Chinese Medical Journal 2007; 120(16):1391-1394 1391
Fetal echocardiographic screening in twins for
congenital heart diseases
LI Hui, MENG Tao, SHANG Tao, GUAN Yun-ping, ZHOU Wei-wei, YANG Guang and BI Li-hua
Keywords: twins; ultrasound, heart; malformations; antenatal diagnosis; echocardiography
Background Congenital heart disease (CHD) is the most common congenital disorder at birth. Yagel and colleagues’s
method of heart examination has been proved valuable in finding CHD prenatally in single pregnancies. The aim of this
study was to analyze the frequency of CHD in twin pregnancies and the sensitivity of the method.
Methods A total of 1103 pregnant women with twins were enrolled in this study, including 127 cases with high-risk for
CHD. Five transverse ultrasound measurements were used for fetal heart examination, including the upper abdomen
view, four-chamber view, five-chamber view, pulmonary artery bifurcation view, and three-vessel view. In the fetuses who
were diagnosed with CHD and whose parents requested termination of the pregnancy, autopsy of the fetal heart was
performed after an abortion, and a blood sample was collected from the heart for chromosome evaluation. In the other
fetuses, a close follow-up was conducted by echocardiography within one year after birth.
Results Antenatally, CHD was found in 12 twins, of which 4 were from the high-risk group (3.15%), and 8 from the
low-risk group (0.82%). In 2 pairs of the twins, the two fetuses had a same kind of CHD (one pair had tetralogy of Fallot
(TOF), another pair had rhabdomyoma). Another pair had different types of anomaly (one fetus had TOF, and the other
duodenal atresia with a normal heart). Termination of pregnancy was performed in these three pairs and the autopsy of
the fetal heart confirmed the ultrasound findings. In the other 9 pairs, CHD was detected in one fetus, and a normal heart
in the others. In the cases who received chromosome evaluation, 2 had abnormal chromosomes. During the follow-up
after birth, heart examinations confirmed the prenatal diagnosis in 7 of the 9. The diagnosis of CHD was missed
antenatally in 2 pairs of twins. In both the cases, one fetus was normal, and the other was confirmed as having CHD after
birth (small ventricle septum defect in one, and persistent open ductus arteriosus in the other). Thus, the total frequency
of CHD was 16 (7.3/1000), which was similar to that in single pregnancies. The sensitivity of fetal echocardiography was
87.5% and the specificity was 100%.
Conclusions The frequency of CHD is the same in twin as in single pregnancies. Systemic ultrasound scanning with
five transverse views is effective in diagnosing fetal CHD in twin pregnancies.
Chin Med J 2007;120(16):1391-1394
ongenital heart disease (CHD) is the most common
congenital disorder at birth. Although advances in
medical and surgical treatments over the past decades
have led to a higher survival rate, about half of the
newborns with CHD face the prospect of future surgery,
arrhythmia, heart failure, and even premature death.1,2
is now well recognized that mothers and fetus in twin
pregnancies are at a higher risk of complications and
adverse outcome than in single pregnancies. An excess of
structural anomalies has been observed in twin
pregnancies compared to the single ones.3
malformations in monozygotic (MZ) twins without
twin-twin transfusion syndrome are four times more
common than that in the general population.4
colleagues’ method of heart examination has been proved
valuable in finding CHD prenatally in single
The aim of this study was to analyze the
frequency of CHD in twin pregnancies and the sensitivity
of the method.
A total of 1103 pregnant women with twins (aged 21 to
39 years), who were treated at the Shengjing Hospital of
China Medical University, Shenyang Maternal and Infant
Hospital, and Dalian Maternal and Infant Hospital from
2003 to 2006, were enrolled in this study (conjoined
twins were excluded). Among them, 127 cases were at a
high risk of fetal CHD, and the other 976 at a low risk.
Fetal echocardiography was performed on all the cases
during gestational weeks 20 to 37. Among the cases with
high risk of CHD, 4 had family history of CHD, 16
women had delivered a neonate with malformations, 4
were complicated with diabetes, 21 were elderly pregnant
women, 21 had abnormal amniotic fluid, 19 had fetal
Departement of Obstetrics and Gynecology, Shengjing Hospital of
China Medical University, Shenyang 110004, China (Li H, Meng T
and Shang T)
Departement of Obstetrics, Shenyang Maternal and Infant
Hospital, Shenyang 110014, China (Guan YP and Zhou WW)
Departement of Obstetrics, Dalian Maternal and Infant Hospital,
Dalian 116033, China (Yang G and Bi LH)
Correspondence to: Dr. LI Hui, Department of Obstetrics and
Gynecology, Shengjing Hospital of China Medical University,
Shenyang 110004, China (Tel: 86-24-81361666. Fax: 86-24-
83955119. Email: email@example.com)
This study was supported by a grant from the Bureau of Science
and Technology of Liaoning Province (No.200522500801)
Chin Med J 2007;120(16):1391-13941392
Table. Types of CHD and pregnancy outcome in the 12 twins
No. GW Prenatal diagnosis (Sibling 1/ 2) Twin type Chromosome (Sibling 1/ 2) Pregnancy outcome Postnatal diagnosis (Sibling 1/ 2)
1 22 w TOF/N DZ N / N SVD (35 w) TOF/VSD
2 31 w TOF/N DZ N / N CS (37 w) TOF/N
3 34 w TOF/DA MZ 18 Tri / N Termination (34 w) TOF/DA
4 24 w TGV/N DZ N / N SVD (34 w) TGV/N
5 25 w AVSD/N MZ N / N SVD (36 w) AVSD/N
6 29 w VSD/N DZ N / N CS (38 w) VSD/N
7 26 w DORV/N DZ N / N CS (37 w) DORV/N
8 35 w DORV/N DZ N / N CS (36 w) TGV/N
9 20 w UH/N DZ N / N CS (37 w) UH/N
10 28 w HLHS/N DZ N / N CS (37 w) HLHS/N
11 32 w Mass/Mass MZ N / N Termination (33 w) Rha/Rha
12 23 w TOF/TOF MZ 21 Tri/ 21 Tri Termination (25 w) TOF/TOF
GW: gestational week; TOF: tetralogy of Fallot; N: normal; DA: duodenal atresia; AVSD: atrial ventricular septal defect; VSD: ventricular septal defect; DORV: double
outlet right ventricle; UH: univentricular heart; HLHS: hypoplastic left heart syndrome; DZ: dizygotic twin; MZ: monozygotic twin; Tri: trisomy; SVD: spontaneous
vaginal delivery; CS: cesarean section; Rha: rhabdomyoma; TGV: transposition of the great vessels.
growth restriction (FGR), 23 had been exposed to
teratogen, 5 had other malformations, and 14 had
GE VIVID7 Ultrasound Doppler machine (GE, USA)
with 3.5 MHz or 5 MHz transducer and Acuson Sequoia
512 (Mountain View, USA) with a 6C2 transducer and
fetal echocardiography program (automatic setting from
2.5 MHz to 6 MHz) were used in this study.
The fetal heart scan was performed with the woman in a
supine position, tilted 15º to the left. Five heart transverse
sections were scanned with the method described by
Yagel and colleagues,6
including the upper abdomen view,
four-chamber view, five-chamber view, pulmonary artery
bifurcation view, and three-vessel view.
In case of severe fetal CHD, if the parents requested, the
pregnancy was terminated after being permitted by the
Medical Ethical Committee of the hospitals. Then,
autopsy of the fetal heart was performed after obtaining
consents from the parents. And blood from the umbilical
cord or fetal heart was collected for chromosome analysis.
For fetuses with a normal heart and those non-terminated
cases with CHD, a close follow-up was given until one
year after delivery. Neonatal heart examination was
performed to confirm the accuracy of antenatal diagnosis.
Judgment for types of twin
Dizygotic (DZ) twin pairs were determined by the gender
of the twins, type of the placenta, blood type analysis, and
physical examinations after birth.7
CHD was found in 12 pairs of twins prenatally, of which
4 were from the high-risk group (3.15%, 4/127), 8 from
the low-risk group (0.82%, 8/976). In 2 of the 12 pairs,
the two fetuses had a same kind of CHD (one pair had
tetralogy of Fallot (TOF), and the other had
rhabdomyoma). In another pair, the fetuses had different
types of anomaly (TOF in one, and duodenal atresia in
another). The prenatal and postnatal diagnoses and
outcomes of the 12 twins with CHD are shown in Table.
Among the 1103 cases, 1091 were diagnosed as having
normal fetal heart prenatally. However, in 2 cases of the
1091, heart diseases were found after birth. In both of the
cases, one baby was healthy and the other was confirmed
as having CHD (small ventricle septum defect (VSD,
Φ=5 mm) in one, and persistent open ductus arteriosus in
the other). Thus, the total frequency of CHD in twins was
16 (7.3/1000), which was similar to that in single
pregnancies. The sensitivity of fetal echocardiography
was 87.5% and the specificity was 100%.
Since an excess of structural anomalies has been observed
in twin pregnancies compared to the single ones, it is
necessary to scan fetal structure including fetal heart
prenatally in twins. However, fetal crowding has been
demonstrated to significantly worsen the screening
performance of ultrasonography in twins, owing to the
recently increased number of multiple pregnancies from
assisted reproduction techniques.8,9
experienced equipments have achieved 87% － 91%
sensitivity and 99.8% specificity in the detection of CHD
in twin pregnancy by serial ultrasound examinations.9-11
In this study, the twins were scanned by experienced
operators using the method of Yagel and colleagues,6
which achieved a sensitivity of 87.5% and a specificity of
100%. Also, we found that the total frequency of CHD in
twins was 7.3/1000, which is similar to that in the
single pregnancies (8‰－10‰).12
In the cases at a high
risk of CHD, the detecting rate was even higher (3.15%).
However, since in our cases, two third of the cases
diagnosed with CHD were from the low-risk group, we
suggest that fetal echocardiography should be performed
in all the women with twin pregnancy.
In most of the twins that were diagnosed as having CHD,
only one fetus is affected, and in approximately 15% of
them, both the fetuses are affected by a same structural
It also happened in our study, two twins were
Chinese Medical Journal 2007; 120(16):1391-1394 1393
found having a same CHD in both the fetuses (one pair
was TOF, the other was rhabdomyoma), and one twin pair
was found to have different structural anomaly (one baby
was TOF, another was extra-heart abnormality).
Approximately 1% to 2% of twin pregnancies may face
the dilemma of expectant management versus selective
termination following diagnosis of an anomaly affecting
only one fetus.13
Selective fetocide can be performed by
ultrasound-guided injection of potassium chloride (KCl)
into the fetal heart or into the umbilical cord, this
technique is now well-established and technically
successful in approximately 93% of reported cases before
24 gestational weeks.14
Alternatively, embolization of the
umbilical cord using sclerosant agents (absolute alcohol,
coils, or enbucrilate gel) and umbilical cord ligation or
laser coagulation by fetoscopy were choices for
monochorionic (MC) twin pregnancies since the presence
of placental anatomoses does not allow the injection of
any lethal agent to achieve selective fetocide in MC twin
However, selective termination may in
fact increase the risk of miscarriage and lead to damage
of the co-twin, particularly in MC pregnancies, expectant
management might be considered an alternate strategy in
discordant twin pregnancies. In this study, no parents
chose to selective fetocide but expectant management, we
suggest a careful and completed fetal structure scanning
for such twins.
Chromosome abnormalities are correlated with fetal CHD
and approximately 50% of aneuploidy individuals suffer
from CHD at the same time.18
Our results show that 3
CHD fetuses in the 12 twins with heart disorders had
abnormal chromosome (12.5%, 3/24, two trisomy 21 and
one trisomy 18), while in single pregnancies, the rate was
However, in the studies reported by Paladini and
colleagues, the incidence of aneuploidy was 6.7% in
twins with CHD and 25.9% in singletons.9,19
we suggest amniotic centesis or cord-centesis for twins
with CHD for chromosome analysis although the centesis
is complicated and difficult in twins.
The risk of recurrent fetal CHD is 4%, if the parents have
delivered a fetus with CHD. 20
We found that in twins
with congenital disorders, the incidence of structural
abnormalities in both the fetuses at the same time was
25%, and CHD in the both at the same time was 20%.
Such cases occurred more often in MZ twins, but also
happened in DZ twins. Hereditary factors play an
important role in the pathogenesis of CHD, and heredity
degree is significant higher in twins than in singletons.
However, in 75% of the twins with CHD, the anomaly
occurred in only one of the fetuses, suggesting that CHD
is not only genetically determined, environment in the
uterus and individual gene mutation contribute to the
It is impossible to detect CHD prenatally, because small
VSD cannot be detected by ultrasonography21
ovale foramen and ductus arteriosus are not closed until
birth. These factors limited the sensitivity and specificity
of fetal echocardiography. The sensitivity and specificity
of detecting fetal heart abnormality was 92% and 99.6%
in single pregnancies. 6
And in our study, they are 87.5%
and 100% in twin pregnancies.
It is difficult to differentiate double outlet of right
ventricle (DORV) from transposition of the great vessels
(TGV) and TOF prenatally. A previous study has shown
that the accurate rate of prenatal diagnose for fetus with
conotruncal anomalies is 77%.22
The rate depends on the
operator’s experience, technology, fetal position,
gestational age, amniotic fluid volume, and maternal fat,
etc. In our study, one case was diagnosed as DORV
prenatally, but was confirmed as TGV after autopsy. Both
DORV and TGV have parallel aorta and pulmonary artery;
however, the aorta and pulmonary artery are both from
the right ventricle in DORV; while in TGV, the aorta is
from the right ventricle and the pulmonary artery from
the left. In our view, it is not important to differentiate
conotruncal anomalies prenatally since they have similar
In conclusion, the diagnostic performance of fetal
echocardiography in twin pregnancies is comparable with
that in single pregnancies. Five-transverse sections
screening is simple and effective, time-saving for fetal
heart examination. We suggested fetal echocardiography
for twin pregnancies as a routine clinical examination.
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(Received November 13, 2006)
Edited by LUO Dan