# Anatomy Scan

Source: https://www.pregnancypowerhour.com/tests/anatomy-scan
Last updated: 2026-07-01

> The anatomy scan, also known as the 20-week ultrasound, is a routine mid-pregnancy scan typically performed between weeks 18 and 22 to examine your baby's development.

The anatomy scan is a significant routine ultrasound in your second trimester, offering a detailed, systematic look at your baby's development and well-being. It's a universal recommendation in the US, UK, and most high-income countries, providing a comprehensive overview of how your baby is growing.

## What it is

This scan systematically examines your baby's organs, growth patterns, the location of your placenta, the amount of amniotic fluid, and your cervical length. It's a chance to see many aspects of your baby's anatomy in detail. While it offers a thorough assessment, it's important to understand that it does not detect every possible anomaly. Research, including insights from Cochrane, indicates that the detection rate for major anomalies can vary, often between 40-70% depending on the specific anomaly and the experience of the sonographer.

## When and how it happens

The optimal timing for this scan is typically between weeks 18 and 22 of your pregnancy. It's usually performed transabdominally, meaning the ultrasound wand moves across your belly. In some instances, if your care provider needs a clearer view of your cervix or placenta, a transvaginal approach might be suggested. This scan also offers the opportunity for sex determination, which is usually quite accurate at this stage if you choose to know.

## What the results mean

Sometimes, the scan might reveal a finding that seems concerning, often referred to as a "soft marker." It's common for these findings to resolve on a repeat scan, and many have a low correlation with actual problems. For example, if a specific area needs closer attention, your provider might recommend further monitoring, perhaps through a [Biophysical Profile (BPP)](/tests/biophysical-profile) or an [Umbilical Artery Doppler](/tests/umbilical-artery-doppler) later in pregnancy, to gather more information. Additionally, a cervical length measurement during this scan can help identify if you have a short cervix, which is a risk factor for preterm birth. Your care provider is your best resource for understanding your specific results.

## Questions worth asking

This is your opportunity to gain clarity and feel confident about your care. One option might be to ask your provider to explain what they are seeing as they go along. You get to decide how much information you want in the moment. You might also ask about the next steps if any findings require further investigation. Understanding the purpose of any follow-up, like a [Non-Stress Test (NST)](/tests/non-stress-test) in the third trimester, can help you feel more grounded. Remember, this is a collaborative process, and your questions are valuable. Your provider is your best resource for your specific situation.