What is the purpose of an ultrasound during the first trimester of pregnancy?

The purpose of an ultrasound during the first trimester of pregnancy is primarily to estimate fetal age. During this early stage, accurate dating of the pregnancy is essential for monitoring development and planning prenatal care. The embryonic measurements taken via ultrasound, such as crown-rump length, are highly reliable indicators of gestational age. This information helps healthcare providers establish a timeline for further evaluations, screenings, and interventions throughout the pregnancy.

Determining fetal position typically occurs later in pregnancy, usually in the third trimester, when the fetus has grown significantly and may start to settle into a specific position for delivery.

Assessing amniotic fluid volume is also generally conducted later in the pregnancy when more definitive evaluations of the environment surrounding the fetus are needed.

Checking for fetal anomalies, while sometimes initiated in the first trimester, is usually more comprehensive during the second trimester when structures are more developed and visible. Therefore, the correct understanding of the primary purpose of first-trimester ultrasounds focuses on estimating fetal age.