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.
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 to 24 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.
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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