Fetal echocardiography, also called fetal echocardiogram, allows to create an image of the fetal heart during pregnancy, using sound waves (the same principle as classic prenatal ultrasound). This procedure is non-invasive, poses no risk (because there is no radiation) and allows the anatomical and functional development of the baby’s heart to be seen.
The main objective is to identify congenital heart defects.
However, fetal echocardiography is not indicated in all pregnancies, because it is not justified, except in the case of pregnancy with risk factors. This is why, in general, it is indicated when heart defects are incipient during the usual prenatal ultrasound. Or also when there is one of the risk factors that we will mention later.
Stay here to understand what fetal echocardiography is and how it works.
What is fetal echocardiography?
Fetal echocardiography is a non-invasive method of imaging the baby’s heart. The procedure gives a two- and three-dimensional image of the 4 cavities of the heart and the outflow channels, as well as by means of the spectral and color Doppler effect, it allows the evaluation of blood flows.
On the other hand, it makes it possible to evaluate the heart rate and the hemodynamic state of the baby. That is to say the “animated image” of the functioning of the heart muscle.
In simpler terms, we would say that there are two forms of images that the study will provide:
- Two-dimensional or 2D echocardiogram: Although it receives this name, it is a combination of two and three dimensions (3D). The doctor examines the anatomy and function of the heart chambers as blood flows in and out.
- EcoDoppler : through the use of a physics effect, the device measures the speed with which blood passes from one chamber to another and towards the vessels. It therefore makes it possible to evaluate the dynamics of the fluid between the different parts of the heart and the real-time functioning of the valves. According to experts, this is one of the scans almost always requested as part of a high-risk exploit.
When should this be done?
Fetal echocardiography can be performed during the first trimester of gestation, between weeks 11 and 14. Before week 10, the formation of the septum of the heart and the development of the valves are not complete. Therefore, the images would not provide useful information.
In turn, the transabdominal route for ultrasound is recommended between weeks 18 to 24 of gestation (second trimester). After the 30th week, the bony structures of the fetus, as well as the air in the lungs, prevent a good view of the heart.
In summary, the ideal times for the study are the intervals of weeks 11-14 and 18-24.
What are the indications for fetal echocardiography?
As mentioned, fetal echocardiogram is not performed in all pregnancies. It is indicative in pregnancies where there are strong suspicions of heart defects. Therefore, it is assumed that this study would certify an initial suspicion of something that was visualized in the usual prenatal ultrasound.
It should also be performed in women who have certain risk factors, such as the following, reported by the medical literature on the subject:
- Maternal phenylketonuria.
- Known genetic alterations.
- Family medical history of congenital heart defects.
- Metabolic (gestational diabetes and high blood pressure) or inflammatory (lupus) maternal diseases.
- Maternal viral infections: rubella, toxoplasmosis, cytomegalovirus, measles and human immunodeficiency virus (HIV).
- Maternal use of cardiac teratogens: indomethacin, steroids, tobacco, alcohol, amphetamines, progestins and anticonvulsants.
- Highly complex reproduction techniques by egg donation or intracytoplasmic sperm injection.
- Twin pregnancies, especially those sharing a single (monochore) placenta
- History of pregnancy with congenital malformations.
And increased nuchal translucency appears on routine follow-up ultrasound, a fetal echocardiogram should be performed. This is how a review of the year 2016 says it. And also each time a sonographer finds a result that raises doubts; not only in the shape of the heart, but also in regard to the rhythm of heartbeats.
How is the procedure?
The procedure for fetal echocardiography is virtually the same as that for a prenatal ultrasound. It is performed in a dark room, with the pregnant woman lying on a stretcher. More frequently the transabdominal technique is used, but during the first trimester the transvaginal technique may be indicated.
In the case of the transabdominal procedure, a conductive gel is placed on the abdomen which allows the sound wave to travel from the device to the baby’s heart and back. This allows the images to be displayed on a monitor.
The procedure usually takes no more than 30 minutes to 1 hourbut it will depend on the position of the baby, the structures to be explored and any malformations found, as well as the gestational age and the experience of the performing physician.
The results will be given the same day in case of emergency. Although sometimes more time is needed for a detailed assessment by specialists.
When the fetal echocardiogram detects a heart defect, it will be the pediatric cardiologist who will explain in detail the findings and the procedure to follow to the parents.
It is not painful and poses no risk
Fetal echocardiography is a harmless, non-invasive and painless procedure. The mother may feel some pressure when inserting the transducer, but nothing else. It also does not require any prior preparation.
The importance of fetal echocardiography screening
Fetal echocardiography detects up to 90% of congenital heart disease. Although its objective is their early detection, some defects can sometimes only be certified upon delivery. These include slight valve problems or small communications between the cavities.
Congenital heart defects are the most common birth defects and moreover, they are a common cause of death in the neonatal stages and in the first year of the baby’s life. This is why, at present, fetal echocardiography is offered as part of a screening for all pregnant women.
However, this is not yet part of the studies that are requested each term, in a normal pregnancy. If your obstetrician or sonographer has any doubts, they will order this procedure.