Biparietal diameter measurement method at 32 weeks of pregnancy. Biparietal diameter measurement at 32 weeks of pregnancy is a very important examination. It can be used to determine the growth and development of the fetus and whether there are any abnormalities in the baby. Typically, biparietal diameter is measured via ultrasonography. Let’s take a look at how to measure biparietal diameter at 32 weeks of pregnancy. Before having an ultrasound, you need to make sure your bladder is fully full. The doctor will ask for