Affiliated Physicians: Maternal Fetal Medicine
What is an ultrasound?
An ultrasound scan is a diagnostic technique which uses high-frequency soundwaves to create an image of the internal organs. A screening ultrasound is sometimes done during the course of a pregnancy to monitor normal fetal growth and verify the due date. Ultrasounds may be performed at various times throughout pregnancy for different reasons:
In the first trimester:
- To establish the dates of a pregnancy
- To determine the number of fetuses and identify placental structures
- To diagnose an ectopic pregnancy or miscarriage
- To examine the uterus and other pelvic anatomy
- In some cases to detect fetal abnormalities
Mid-trimester: (sometimes called the 18 to 20 week scan)
- To confirm pregnancy dates
- To determine the number of fetuses and examine the placental structures
- To assist in prenatal tests such as an amniocentesis
- To examine the fetal anatomy for presence of abnormalities To check the amount of amniotic fluid
- To examine blood flow patterns
- To observe fetal behavior and activity To examine the placenta
- To measure the length of the cervix
- To monitor fetal growth
Third trimester:
- To monitor fetal growth
- To check the amount of amniotic fluid
- As part of a biophysical profile
- To determine the position of a fetus
- To assess the placenta
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