Biparietal Diameter Bpd Ultrasound Normal Range

The biparietal diameter measurement increases from roughly 2 4 centimeters at 13 weeks to approximately 9 5 centimeters when a fetus is at term.

Biparietal diameter bpd ultrasound normal range.

Your doctor is looking for the bpd measurement as well as the other measurements to be within what is considered normal range. Bpd together with head circumference hc abdominal circumference ac and femur length fl are computed to produce an estimate of fetal weight. Measurements within the normal range can also be assessed. Reference ranges for fetal head ultrasound biometry have been reported by a number of investi gator.

Different babies of the same weight can have different head size therefore dating in the later part of pregnancy is generally considered unreliable. The use of the biparietal diameter bpd. Measurements of the fetal biparietal diameter bpd and head circumference hc have become established methods of assessing fetal size1 and determining gesta tional age4 5. In the second trimester this may be extrapolated to an estimate of gestational age and an estimated due date edd.

Royston and wrighti4 and altman15 have. 18 limited to the 12 25 week interval. Biparietal diameter bpd in 27 fetuses with open spina bifida measured at 11 13 week scan and in the same fetuses between 16 and 24 weeks when spina bifida was detected plotted on the modified bpd reference range of kurmanavicius et al. The range of bpd values for each week of pregnancy from 12 weeks until term 713 measurements was computed from cross sectional data.

Biparietal diameter bpd is one of the basic biometric parameters used to assess fetal size. The fetal biparietal diameter bpd was measured by ultrasound during normal pregnancy in 558 nigerian women. Since all of these measurements are strongly related to gestational age it is not usually important how they are combined. Biparietal diameter bpd this is the diameter between the two sides of the head and is measured after 13 weeks.

It increases from about 2 4 cm at 13 weeks to about 9 5 cm at term. Ultrasound obstet gynecol 1994 4 34 48 the patients fulfilled the following. Gestational age was calculated from the first day of the last menstrual period lmp and confirmed either by an ultrasound crown rump length measurement during the first trimester or by an estimate based on multiple ultrasound parameters biparietal diameter bpd head circumference hc abdominal circumference ac and femur length fl of. Itisrecommendedthatdepartments whichadoptthecharts tables in this document check that any data programmed into their ultrasound and computerised patient management sys tems use the ga and size equations given here.

Normal deviations are shown in brackets in the chart below.