Which ultrasound criteria is considered the most reliable for dating in pregnancy?

The transcerebellar diameter is considered one of the most reliable measurements for dating pregnancy due to its ability to minimize variability influenced by fetal growth patterns and the gestational age. The cerebellum tends to develop in a consistent and predictable manner, which allows for more accurate dating when assessed via ultrasound.

This measurement offers a robust correlation with gestational age and provides a stable reference throughout most stages of pregnancy. It is particularly advantageous in the second and third trimesters when other measurements may be affected by factors such as fetal positioning, individual growth variation, or anomalies.

While parameters like head circumference (HC), biparietal diameter (BPD), and abdominal circumference (AC) are also used in dating, they can be influenced more significantly by factors such as fetal abnormality, growth restriction, and maternal diabetes, making them less reliable than the transcerebellar diameter for precise dating.