Biparietal diameter

The biparietal diameter , or BPD or BIP for short , is the transverse diameter of the child's head in the womb. It is measured during ultrasound examinations in order to be able to draw conclusions about the development status and possible undesirable developments (e.g. hydrocephalus ) of the fetus .

For the measurement, the doctor marks both sides of the child's head on the ultrasound image. The BPD is calculated by the device and is often noted on the printouts of the ultrasound images.