The test is typically performed by a specially trained ultrasound sonographer and the images are interpreted by a pediatric cardiologist who specializes in fetal congenital heart disease. Some maternal-fetal medicine specialists (perinatologist) also perform fetal echocardiograms. A limited evaluation of the fetal heart is possible during regular obstetric scanning and is appropriate for women at low risk. However, women who have one of the risk factors listed above should have a detailed fetal echocardiogram performed by a physician who is specially trained in fetal cardiac evaluation.
There are two ways to perform a fetal echocardiogram:
- Abdominal ultrasound: this is the most common form of ultrasound to evaluate the baby's heart. There is gel applied to the mother's abdomen, the ultrasound probe is gently placed on the mother's abdomen and pictures are taken. This test is not painful and causes no harm to the baby. The test takes an average of 45–120 minutes depending on the complexity of the baby's heart.
- Endovaginal ultrasound: this ultrasound is typically used early in pregnancy. A small ultrasound transducer is inserted into the vagina and rests against the back of the vagina. Pictures can then be taken of the baby's heart.
Is there any preparation needed for the test?
Unlike some routine prenatal ultrasounds, a full bladder is not necessary for a fetal echocardiogram. It is always important to have as much information as possible when you come for your fetal echocardiogram; especially the details of why you were referred by your obstetrician or perinatologist. If the reason for referral is that you have a heart defect yourself, bringing whatever medical records you have will be very helpful. The study can take anywhere from 30 minutes to over 2 hours depending on what the findings are; it is always a good idea to bring another care giver if you have other small children with you.
When will I get answers?
The answers that are available will depend on the setting of the fetal echocardiogram, gestational age of the fetus, diagnoses, and quality of the pictures. If the study is being performed by a pediatric cardiologist, the pediatric cardiologist will meet with you as soon as the study is completed and provide you with a detailed explanation of the results. If your initial study is performed by a perinatologist and a heart defect is found, you will be referred to a pediatric cardiologist for more detailed diagnosis and counseling.
If the study is normal, you may be discharged, or asked to have a repeat study before or after birth depending on the reason the study was performed in the first place. Some problems such as maternal lupus require several studies even if the first one is normal. There also may be a structure that is not seen as well as the doctor would like, and you may be asked to return even though the suspicion of a problem is low. Even in the case of a totally normal, high quality study, you will be counseled that not all heart problems can be ruled out. This is because the circulation in the fetus is different than after birth. Additionally, very small holes between the lower chambers of the heart are hard to see. However, considering the normal fetal circulation, you doctor can provide fairly definitive good news in the case of a normal fetal echocardiogram.
Fetal echocardiograms can reliably be performed any time after 17–18 weeks gestation; however, newer technology including endovaginal transducers can obtain images of the heart as early as 12 weeks. If scanning is done before 18 weeks, you will likely be asked to return for more definitive pictures to confirm the findings on the early study. In some cases 18 weeks is still too early.
When a heart defect is found, the pediatric cardiologist will explain in detail the diagnosis and implications as soon as the study is completed. In most cases the doctor may take additional pictures after the sonographer has completed the initial study. The pediatric cardiologist will likely provide and draw pictures to explain the significance of the heart defect including whether or not the defect will affect the fetus prior to birth, require immediate transfer after birth, and need heart surgery after birth. In almost all cases you will be asked to return for follow up fetal echocardiograms to obtain more information as you prepare for delivery. Your pediatric cardiologist will give you as much information as possible and also inform you of what questions still remain. Your future visits may include meeting with a cardiac surgeon or interventional cardiologist to learn more about heart surgery or other procedures after birth.
The diagnosis of heart defect has significant implications for the overall health of the fetus; certain heart defects may significantly increase the risk of genetic problems such as Down Syndrome or DiGeorge Syndrome. The finding of benign tumors in the heart makes the diagnosis of Tuberous Sclerosis, a genetic syndrome that has significant implications for abnormal brain development much more likely. These issues may have significant implications on the prognosis of the child and play a major role in helping you make decisions about your pregnancy. Your cardiologist will provide you with information about whether or not you need to worry about these other issues; however, when the concern is significant you will be referred to other members of the care team that work closely with the pediatric cardiologist:
Other tests, procedures, and referrals that may be needed include the following:
- High level fetal ultrasounds A detailed ultrasound of the rest of the fetus is necessary to follow fetal growth, monitor fetal well-being, and assess the rest of the fetus for abnormalities in other organs.
- Fetal MRI This test is becoming more widely available and can provide additional information about the overall health of the fetus and problems with certain organs.
- Genetic counseling Geneticists and genetic counselors provide an assessment of the likelihood of a genetic syndrome and possible abnormalities in other organs based on the heart diagnosis and other findings in the fetus. The geneticist can provide 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.
- Perinatologist Perinatologists can advise you about the management of your pregnancy, options for deciding whether on not to continue the pregnancy, and planning for delivery
- Social worker/Nurse Someone who is familiar with heart disease in children, can provide information about caring for a child with congenital heart disease.
Amniocentesis This is 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. - Specialist consultation Depending on the diagnoses you may be referred to other subspecialists including general surgeons, neurosurgeons, orthopedic surgeons, and urologists.
