BPD
Also written as: BPD — biparietal diameter
Biparietal diameter - the measurement across the widest part of the fetal head used for gestational age assessment.
Full Definition
Biparietal diameter (BPD) is a standard biometric measurement in obstetric ultrasound, taken from the outer edge of the proximal parietal bone to the inner edge of the distal parietal bone at the level of the thalami and cavum septi pellucidi. It is one of the key parameters used to estimate gestational age and fetal weight, particularly accurate in the second trimester. Proper measurement technique is critical as head shape variations can affect accuracy, requiring correlation with other biometric parameters.
Usage
Usage note: Always write out as 'biparietal diameter' on first use; commonly abbreviated in serial measurements.
In Context
- "The BPD measured 95mm, consistent with 36 weeks gestation." — Ultrasound report
- "Fetal biometry showed BPD, HC, AC, and FL all tracking on the 50th percentile." — Growth assessment report