Abdominal circumference
Abbreviation: AC
Abdominal circumference (AC) is the measurement taken around your baby's belly during an ultrasound scan. It is one of the key measurements used in your second and third trimester anomaly and growth scans. AC reflects the size of your baby's liver and the amount of fat stored under the skin, making it a good indicator of overall nutrition and growth. When combined with head circumference, femur length, and biparietal diameter, it helps your doctor estimate your baby's weight and check whether growth is on track. A reading that is too small or too large may prompt closer monitoring or further investigation.
What This Means for You
Understanding Abdominal circumference is an important part of your second/third trimester journey. During pregnancy, your care team will use this term regularly. Being familiar with it means you can ask better questions and feel more confident at your antenatal appointments.
Explore our Pregnancy hubGood to Know
At KKH and NUH, AC is routinely measured at the 20-week anomaly scan and again at growth scans in the third trimester. A single reading outside the normal range does not automatically mean a problem, as serial measurements over time give a more complete picture.
Related Terms
Source: https://www.acog.org/womens-health/faqs/how-your-fetus-grows-during-pregnancy
Always consult your healthcare provider for personalised advice.
Free Tools for Singapore Parents
Put your knowledge into action with our free calculators and trackers.