There are many types of prenatal ultrasounds that may be performed during the course of a pregnancy. The following are examples.
Evaluation of Fetal Development, Position, Amniotic Fluid (Level 1)
This type of ultrasound is usually performed after you have had the initial full anatomical evaluation of your baby and follow-up evaluation is recommended. In some cases your doctor or midwife may be concerned about the baby’s position and/or size and will request an ultrasound evaluation of your baby’s growth pattern.
Genetic Anatomical Ultrasound (Level 2)
Detailed evaluation of the fetal anatomy including measurements of the head, body, and extremities as well as careful observation of any structures able to be visualized by ultrasound. Routinely performed after 18 weeks of pregnancy, the anatomical evaluation can also be used to make a genetic risk assessment for your pregnancy in conjunction with any other genetic screening you may have had earlier in the pregnancy.
This type of ultrasound entails special ultrasound imaging of the heart and its major vessels, including blood flow studies (Doppler). Our perinatal center performs fetal echocardiography beginning in the second trimester. This procedure is not necessary for every baby as the heart is extensively evaluated during the anatomical ultrasound. A fetal echocardiogram may be offered if a physician feels that further study of the baby’s heart is necessary due to risk factors in your history (medical or family). An echocardiogram may be recommended if there is a suspected fetal abnormality during your anatomical ultrasound.
An ultrasound performed through placement of a slim ultrasound probe vaginally. This is recommended for better visualization of the baby in early pregnancy. This ultrasound evaluation is especially useful in patients with cramping, spotting or preterm contractions. It allows for an accurate measurement of your cervix and determines your risk for preterm delivery.
Assessment of the baby’s well-being by observation of specific fetal movements and the amniotic fluid level.
3D Ultrasound Imaging
Provides a more detailed evaluation for certain parts of the fetal anatomy for suspected fetal abnormalities such as cleft lip, cleft palate and spine abnormalities (i.e. spina bifida).
Ultrasound Assessment of the cervix
Internal ultrasound especially useful in patients at risk for preterm delivery.
Assessment of the baby’s well-being by observation of specific fetal” movements and the amniotic fluid level.
First Trimester Screening (FTS)
Using a combination of ultrasound measurements, maternal age, and maternal serum biochemical markers, about 90% of babies at risk for Down syndrome and Trisomy 18 can be detected.
Screening takes place between approximately 11 and 14 weeks of pregnancy*. The screening in the first trimester is unique from screening typically done in the second trimester as it involves a combination of ultrasound (nuchal translucency [NT]) and a blood test in conjunction with your maternal age. The results of the First Trimester Screen will then be discussed with you as to whether you desire more definitive testing (i.e. CVS or amniocentesis). Our practice is one of the few centers in central Pennsylvania certified to perform First Trimester Screen utilizing NT measurements.
*The gestational ages listed are an estimate of the time to have FTS. The actual criteria for performing FTS is dependent on the crown-rump measurement (CRL) at the time screening is performed.