Several diagnostic ultrasound tests are performed at the ATC, with specialized ultrasonography per the American Institute of Ultrasound in Medicine guidelines:
First Trimester Ultrasound: The exam confirms the intra-uterine location of the gestation, allows precise dating of the pregnancy, establishes the number of fetuses and fetal cardiac activity. Major fetal anomalies can be ruled out. If desired, a genetic screen can be performed inclusive of nuchal translucency.
Second Trimester Ultrasound: The main goal of such exam is to rule out the presence of fetal anomalies. A targeted (or “Level II) exam is performed in the presence of specific risk factors that significantly increase the woman’s risk of structural fetal anomalies above the background risk for all pregnancies. The scan also allows evaluation for any anomalies of placental implantation or umbilical cord attachment which may affect fetal growth or timing of delivery.
Third Trimester UItrasound: A follow-up scan is frequently required to monitor fetal growth in the presence of risk factors for poor fetal growth (e.g. maternal chronic hypertension or other medical conditions potentially affecting placental function and fetal growth) or for excessive fetal growth (e.g. in the presence of maternal diabetes).
Fetal Echocardiography: This specialized test is meant to rule out the presence of fetal cardiac anomalies in the presence of specific risk factors. Not all cardiac anomalies are amenable to prenatal diagnosis: some anomalies manifest only later in pregnancy or only in the neonatal period.
Transvaginal Ultrasound: This type of exam is performed to assess the cervical length (which is an important predictor of risk of preterm delivery) in the presence of risk factors for preterm birth. Moreover the exam allows to rule out presence of placental tissue or fetal vessels in proximity of the cervix, which would constitute a contraindication for vaginal delivery.
Color and Pulse Wave Doppler Flow Imaging: This specialized exam allows to document blood flow in fetal or maternal vessels. Typical indications include conditions which may affect placental perfusion or may cause fetal anemia.
In addition to the above, tests to document fetal well-being are routinely done at the ATC including:
Non-Stress Testing: This test consists in monitoring fetal heart rate for at least 20 minutes. A reassuring pattern indicates that the fetus is well oxygenated.
Biophysical Profile: (which consists of documentation of types and duration of fetal movements) is done if the test result is non-reassuring, or as stand-alone test to document reassuring fetal status.
Finally, our Maternal-Fetal Medicine physicians can perform the following procedures when indicated:
Genetic Amniocentesis: The procedure allows access to a small amount of amniotic fluid, which contains fetal cells. Different genetic tests can be performed on such fetal cells, including karyotype analysis (which is the definitive study to rule out chromosome anomalies, such as Down syndrome), microarray analysis (to investigate subtle chromosome anomalies, such as microdeletions and microduplications, which are more common in the presence of fetal structural anomalies), or exome sequencing (in very specific cases). Amniocentesis is a diagnostic procedure (i.e. it allows to make specific genetic diagnoses) but it is invasive (as it involves a needle insertion inside the amniotic cavity), and as such it carries a small risk of complications including fetal loss due to the procedure.
External Cephalic Version: The procedure is offered to women with a fetus in non-cephalic presentation at or near term. It consists of manipulation of the fetus through the maternal abdomen to guide the fetal head into a head down (cephalic) position. An ultrasound scan is performed prior to the procedure to rule out the presence of contraindications. At that time, pertinent information is given to the patient, any question is answered, and the patient’s individual circumstances and preferences are discussed.
Cervical Cerclage Placement: This surgical procedure is performed in the presence of an obstetric history suggestive of cervical insufficiency/incompetence, or in the presence of cervical shortening of a degree suggestive of increased risk for preterm delivery in the ongoing pregnancy.