BPD - OFD - HC | Femur and Humerus (FL HL) | Abdominal Circumference (AC) Fetal Weight Percentile Charts | Fetal Growth Percentile Charts Measurement Standards | Ultrasound Measurement Chart | Crown-Rump Length After the first trimester of pregnancy a multiparameter assessment of gestational age is advocated.
The BPD is measured from the outer edge of the nearer parietal bone to the inner edge of the more distant parietal bone. The long bones are measured with the bone across the beam axis.
This is preferable to just averaging all values to arrive at an estimated gestational age.
The wide normal range of BPD in late pregnancy must be appreciated.
When the date of the last menses preceding conception is known, it is usually a more accurate estimate ( /- 5 days) of EDCWhen using ultrasound to estimate gestational age, remember that we are assuming the fetus is growing normally.
Conditions which alter fetal growth will make the estimates less reliable.