THE FETAL ECHOCARDIOGRAM PROCEDURE
Fetal echocardiography is an ultrasound test that’s very similar to that conducted in adults. High-frequency ultrasound waves are used that echo off the heart’s structures and are then picked up by machines to create an image, thereby enabling the doctor to visualize the interior structure and function of the unborn child’s heart. The scan enables accurate imaging of the hearts musculature, chambers and other structures including the valves. The test basically looks for any abnormalities in the heart, with one in every hundred babies being born with a heart defect. Abnormalities of the heart are the commonest defects that babies are born with.
Sometimes this test is just referred to as an echo scan and is usually carried out between the 18nth to 24th week of pregnancy. It normally takes about 30-120 minutes to collect sufficient images of the heart.
Some women are more prone to giving birth to babies with congenital heart diseases and such scans are very helpful in diagnosing the problem within the womb itself as it helps the baby have faster access to medical and surgical help upon delivery (if needed). An early diagnosis also helps in better management of the pregnancy. About 1% of babies are born with congenital heart abnormalities like holes in the heart, narrowed arteries, abnormal heart rhythms, defective valves, etc.
Fetal echocardiograms are not recommended routinely and just a basic ultrasound is usually enough; however if the obstetrician detects any abnormalities in the ultrasound scan or the fetal heart rhythm, he may prescribe an echogram too. Other situations where it is requested include, the mother having certain health issues like type 1 diabetes, lupus or connective tissue diseases, or having taken some particular medications that induce fetal abnormalities or if she has a history of alcohol and drugs or a history of congenital heart disease in the family.
Some obstetricians prefer to conduct the test themselves, but it’s usually an experienced ultrasonographer who performs the scan; a cardiologist specialized in pediatric medicine then reviews the results. There is no preparation for this test and the bladder doesn’t need to be full.
There are two ways to doing the fetal echogram. When it’s done through the abdomen, it’s known as abdominal echocardiography and when it’s done transvaginally, it’s known as transvaginal echocardiography.
Abdominal echocardiography is more common and similar to an abdominal ultrasound. The mother is made to lie down on her back and a jelly is applied on her exposed belly to prevent friction from the ultrasound transducer as well as to help in transmitting high-frequency sound waves. The technician moves the transducer at various angles over the belly to get different images of the fetal heart.
In transvaginal echocardiography, the probe is inserted through the vagina and usually gets better images of the fetal heart. This route is normally used in the earlier stages of the pregnancy.
The images produced are then reviewed by a specialist and diagnosis passed on to the patient.