As you embark on your pregnancy journey, you're probably thinking that your ultrasound test is exciting -- but pretty straightforward. It's just a procedure that most doctors recommend to assess your and your baby's prenatal health, right? Yes, but it can also determine many important factors of a pregnancy: how the baby is developing, how far along your pregnancy is, or if any congenital abnormalities are present. Furthermore, there are a variety of ultrasound tests that you can undergo depending on your personal circumstances, so it's important to know the differences. By arming yourself with the proper knowledge, you'll be ready to make the right decision with your doctor.
The transabdominal ultrasound is the standard ultrasound test that produces a two-dimensional image of the developing fetus. Other sonograms follow a procedure similar to this one.
You will lie on your back or side on an exam table. An ultrasound technician will spread a warm gel over your lower abdomen to help the movement of the sound waves that generate the sonogram image. Next, the ultrasound technician will move a transducer, which is a device that sends and receives sound waves, across your abdomen.
The transvaginal ultrasound is generally utilized during the early stages of pregnancy. Instead of being performed on the surface of the abdomen, a transvaginal ultrasound uses a probe transducer inside the vagina to produce sonogram images. You will lie on your back on the exam table and put your feet in stirrups, as if you were undergoing a gynecological exam.
3-D and 4-D/Dynamic Ultrasounds
3-D and 4-D ultrasounds use software that generates more complex images of the developing fetus than can be produced with standard ultrasounds. A 3-D ultrasound can show the doctor the depth, width, and height of the fetus. A 4-D ultrasound also uses scanners to produce a video of the fetus, showing the face and movements.
This ultrasound test determines fetal heart anatomy and function, alerting your doctor to any possible congenital heart defects. A fetal echocardiography produces an image of a fetus's heart size, shape, and structure.
"Your doctor will perform a fetal echocardiography if it's suspected that the fetus is at risk for a congenital heart defect," says Dr. Nadine Lyseight, a board-certified OB/GYN of Dignity Health Medical Group - Inland Empire.
For this procedure, an ultrasound technician will use a transducer to listen to the fetus's heartbeat and measure blood flow to see how the fetus is growing. A Doppler ultrasound is typically performed during the last trimester of pregnancy.
Amniocentesis is a test in which a sample of amniotic fluid is removed from the sac surrounding the fetus to check for certain birth defects. The fluid is extracted using a needle inserted into the uterus through the abdomen. Ultrasound is used to guide the needle into the uterus. The sample is then sent to a laboratory for analysis.
"Amniocentesis does carry a slight risk, so it's typically performed only on older mothers or those who have risk factors for certain birth defects," said Dr. Lyseight. Talk to your doctor about the risks and benefits, and make a final decision together.
When performed under the guidance of a trained technician to determine the health and status of your pregnancy, ultrasounds are safe and important procedures. Keepsake sonograms, especially 3-D ultrasounds for nonmedical purposes, are safe overall but not without some risk.
Just like with other aspects of your pregnancy, you want to be in lockstep with the medical professionals you're working with regarding your ultrasound test. In the end, know that too much exposure to any type of ultrasound may not be good for your baby, so it's best if any procedure you undergo is both requested and approved by your doctor.