Facts

The following facts and observations are important to consider when attempting to find a solution to this dilemma.

1. 3D/4D ultrasound of the fetal facial features is desirable by many patients for bonding and other purposes.

This illustrates blinking of the eyes of two fetuses at 28 and 30 weeks of pregnancy.

2. Almost all indicated fetal ultrasound examinations are performed between 8 and 22 weeks of pregnancy. Because of many factors such as fetal size, maternal adipose (fatty) tissue, fetal position, etc. fetal ultrasound examinations during this time of the pregnancy are the most difficult to perform and interpret.

This illustrates the times in pregnancy that various types of ultasound studies are performed.

 

3. Although prenatal diagnosis of congenital heart disease in high-risk patients can occur between 13 and 22 weeks of pregnancy, the time between 24 and 32 weeks is the most optimal from an imaging perspective. The reason for this is because of the size of the fetal heart that allows for improved imaging, as well as the potential to identify late-onset heart defects that may not have been visible earlier in pregnancy.

4. In addition, the best time to image the soft tissue features of the face is during this time period. Prior to 24 weeks 3D/4D ultrasound may be used to examine the bones of the fetal face and skeleton, evaluate the suture lines of the skull, and examine movement of the extremities. While all of these are desirable during earlier studies, the image of the fetal face is the least pleasing to the patient, who often expresses the feeling that the face looks like an "alien."

This is a 2D image of the fetal face (left) and skeleton (right) at 19 weeks. Patients often refer to this an an "alien" look. This is because of the size of the fetus and the lack of development of soft tissue that is present later in pregnancy.

These images represent facial characteristics at 24, 28, and 32 weeks of pregnancy. Notice that as the fetus ages, the images become clearer. After 32 weeks, however, imaging of the face is more difficult because of fetal position, decreased amniotic fluid, etc.

 5. One of the problems with the Screening or Standard Ultrasound Examination performed during the second trimester of pregnancy is that it identifies less than 10% of fetuses with congenital heart anomalies; the most common of the serious birth defects. Congenital heart disease has the highest death rate in the first weeks of life. However, for several types of congenital heart abnormalities, prenatal diagnosis may improve the outcome for the newborn baby.

6. Cleft lip and palate are common birth defects, often missed during the Screening or Standard Ultrasound Examination performed during the second trimester of pregnancy. Other than requiring special ultrasound skills to examine the face, the fetal face is not a required image to obtain during this examination.

7. Although ultrasound examinations performed during the first and second trimesters of pregnancy are used to determine the gestational age and the date of delivery, 10% of fetuses grow abnormally during some portion of the the latter 14 weeks of pregnancy. When growth abnormalities occur, this may have long-term effects on the health and well-being of the fetus. Recognition of this problem may improve the outcome of the pregnancy.