Ultrasound - Pregnancy
Obstetric ultrasound refers to the specialized use of ultrasound to visualize and determine the condition of a pregnant woman and her embryo.
Some indications for obstetric ultrasound may be:
- To evaluate the position of the embryo
- To evaluate the position of the placenta
- To determine if there are multiple pregnancies
- To establish a living embryo
- To diagnose congenital abnormalities
- To establish fetus age
- To measure the nuchal translucency of the embryo, to assess the risk of chromosomal abnormalities.
Ultrasound has been widely used to evaluate pregnancy for 30 years and there has been no evidence of any harmful effects to the patient or embryo. However, ultrasound should only be used where clinically indicated.
Obstetric ultrasound cannot identify all embryo abnormalities. Consequently, when there are clinical or laboratory suspicions of a possible abnormality, a pregnant woman may have to undergo non-radiological testing such as an amniocentesis (the evaluation of fluid taken the sac surrounding the embryo) to determine the health of the embryo. An ultrasound for nuchal translucency evaluation involves measuring the skin fold on the back of the neck of the embryo between 11-14 weeks of pregnancy. An increased measurement has shown to be related to an increased risk of chromosomal abnormality and nuchal translucency assessment may be useful in determining whether or not amniocentesis or other testing is appropriate.