Is fetal weight estimated more accurately based on abdominal circumference or biparietal diameter?

Generally, fetal weight is primarily estimated by combining abdominal circumference and biparietal diameter. The specific analysis is as follows:

Fetal weight estimation is performed using multiple indicators, including abdominal circumference and biparietal diameter. These two parameters are commonly used measurements that provide useful information regarding fetal growth and development. Abdominal circumference refers to the circumference of the fetal abdomen and is typically measured during prenatal ultrasound examinations. By measuring abdominal circumference and biparietal diameter, doctors can indirectly estimate fetal weight, as there is a certain correlation between abdominal circumference and fetal weight. Generally, fetuses with larger abdominal circumferences tend to have higher weights, while those with smaller abdominal circumferences tend to be lighter. However, abdominal circumference-based estimations are not 100% accurate, as fetal weight is also influenced by other factors such as maternal nutritional status, gestational age, and genetic factors. Biparietal diameter refers to the distance between the two outermost points on either side of the fetal head and is also measured via prenatal ultrasound. This measurement provides information about fetal head circumference and cranial development.

Fetal weight estimation serves only as a reference, and actual birth weight may differ to some extent. Accurate estimation of fetal weight is crucial for clinical management and monitoring of fetal development, but the definitive weight must ultimately be confirmed by weighing the newborn at birth.