Fetal Echocardiography
What is fetal echocardiography?Fetal echocardiography is an ultrasound test performed during
pregnancy to evaluate the heart of the unborn baby.
Echocardiography assesses the heart's structures and function. A small
probe called a transducer (similar to a microphone) is placed on the
mother's abdomen and sends out ultrasonic sound waves at a frequency too
high to be heard. When the transducer is placed in certain locations and
at certain angles, the ultrasonic sound waves move through the mother's
and baby's skin and other body tissues to the baby's heart tissues, where
the waves bounce (or "echo") off of the heart structures. The transducer
picks up the reflected waves and sends them to a computer. The computer
interprets the echoes into an image of the heart walls and valves.
Fetal echocardiography can help detect fetal heart abnormalities before
birth, allowing for faster medical or surgical intervention once the baby
is born. This improves the chance of survival after delivery for babies
with serious heart defects.
When is a fetal echocardiogram necessary?It is not necessary for all pregnancies to receive an
echocardiogram. The prenatal ultrasound tests that are done prior to birth
can give information about whether the fetal heart has developed with all
four chambers. Most unborn babies do not require any further testing.
Situations in which a fetal echocardiogram may be necessary include,
but are not limited to, the following:
- if a sibling was born with a congenital (present at birth) heart
defect
- a family history of congenital heart disease (such as parents, aunts
or uncles, or grandparents)
- a chromosomal or genetic abnormality discovered in the fetus
- if a mother has taken certain medications that may cause congenital
heart defects, such as anti-seizure medications or prescription acne
medications
- if the mother has abused alcohol or drugs during pregnancy
- if a mother has diabetes, phenylketonuria, or a connective tissue
disease such as lupus
- if the mother has had rubella during pregnancy
- a routine prenatal ultrasound has discovered possible heart
abnormalities
Fetal echocardiograms are usually performed in the second trimester of
pregnancy, at about 18 weeks. The test is sometimes done earlier in
pregnancy using transvaginal ultrasound (the ultrasound probe is inserted
in the mother's vagina), but will be repeated later to confirm any
findings.
How is a fetal echocardiogram performed?A fetal echocardiogram is performed by a pediatric cardiologist
or a maternal fetal specialist (also called a perinatologist) who is
specially trained. The test may be done using an abdominal or transvaginal
ultrasound.
- abdominal ultrasound
In an abdominal ultrasound, gel is applied to the abdomen and the
ultrasound transducer glides over the gel on the abdomen to create the
image.
- transvaginal ultrasound
In a transvaginal ultrasound, a smaller ultrasound transducer is
inserted into the vagina and rests against the back of the vagina to
create an image. A transvaginal ultrasound produces a sharper image than
abdominal ultrasound and is often used in early pregnancy.
During the test the transducer probe will be moved around to obtain
images of different locations and structures of the fetal heart.
Techniques sometimes used to obtain detailed information about the fetal
heart include the following:
- 2-D (2-dimensional) echocardiography
This technique is used to "see" the actual structures and motion of
the heart structures. A 2-D echo view appears cone-shaped on the
monitor, and the real-time motion of the heart's structures can be
observed. This enables the physician to see the various heart structures
at work and evaluate them.
- Doppler echocardiography
This Doppler technique is used to measure and assess the flow of blood
through the heart's chambers and valves. The amount of blood pumped out
with each beat is an indication of the heart's functioning. Also,
Doppler can detect abnormal blood flow within the heart, which can
indicate such problems as an opening between chambers of the heart, a
problem with one or more of the heart's four valves, or a problem with
the heart's walls.
- color Doppler
Color Doppler is an enhanced form of Doppler echocardiography. With
color Doppler, different colors are used to designate the direction of
blood flow. This simplifies the interpretation of the Doppler images.
Fetal echocardiography can help detect fetal heart abnormalities before
birth, allowing for faster medical or surgical intervention once the baby
is born. This improves the chance of survival after delivery for babies
with serious heart defect. Other tests or procedures that may be needed
include the following:
- additional ultrasounds or echocardiography (to confirm the
diagnosis, follow fetal growth, and monitor fetal well-being)
- amniocentesis - a test performed to determine chromosomal and
genetic disorders and certain birth defects. The test involves inserting
a needle through the abdominal and uterine wall into the amniotic sac to
retrieve a sample of amniotic fluid.
- genetic counseling - providing an assessment of heritable
risk factors and information to patients and their relatives concerning
the consequences of a disorder, the probability of developing or
transmitting it, and ways in which it can be prevented, treated, and
managed.
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