Most pregnant women are familiar with the transducer ultrasound used to show images of the fetus in the womb, but the transducer is not the only type of ultrasound used during pregnancy. Ultrasound images can be used to determine the conception date, gestational age of the fetus and fetal size. Imaging is also used to assess the health and growth rate of the fetus, measure the placenta and track amniotic fluid levels. The type of ultrasound used depends on the gestational age when the ultrasound is ordered and the reason for the ultrasound.
Transducer Ultrasound
Mom bears her growing belly and special jelly is used to enhance Doppler images of the fetus. The transducer ultrasound bounces sound off internal organs and the fetus and processes the returned sounds into images.
Transvaginal Ultrasound
Transvaginal ultrasounds use transducer technology, but the images needed are too small to be seen through the abdominal wall. A wand is covered with a condom and lubricated before being inserted into the vagina. The doctor can see the smallest details, including a fetus too small for the abdominal transducer. Transvaginal ultrasounds are also used for other reproductive diagnosis requiring images of the ovaries and other reproductive organs.
3D Imaging
3D ultrasounds use the same technology as transducer ultrasounds, but more sound reflections are processed creating a 3D image. The technology is the same trusted technology that has been used for more than 30 years, but images are processed on more advanced computers. Gender-seeking parents can schedule appointments as early as 16 weeks gestation, but baby really starts looking like an infant between 28 and 34 weeks gestation.
4D Imaging
4D imagining is the same as 3D imaging and transducer ultrasound, but the images are processed continuously giving parents the opportunity to see baby in action.
Differences Between Transducer, 3D and 4D Ultrasounds
Though all three types of ultrasound use the same technology, the images are quite different. The transducer ultrasound can take pictures of fetal organs, while 3D and 4D ultrasounds focus on external images. Most 3D and 4D ultrasounds are voluntary, though some are medically necessary to confirm physical anomalies like cleft lip or amniotic band syndrome.
With advances in medical ultrasound, pregnant women, technicians and doctors have the opportunity to see baby for the first time just weeks after conception and take pictures of a 3D image of a baby sucking their thumb for the first time. The trusted transducer ultrasound is likely going to be a part of your prenatal check-up, but there may be a few additional ultrasounds in order.