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. Measurements of biparietal diameter bpd occipito frontal diameter ofd anterior and posterior. The range of bpd values for each week of pregnancy from 12 weeks until term 713 measurements was computed from cross sectional data. In most cases bpd biparietal diameter hc head circumference ac abdominal circumference and fl femur length are used. 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.

18 limited to the 12 25 week interval. 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. Reference ranges for fetal head ultrasound biometry have been reported by a number of investi gator. 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.

Measurements within the normal range can also be assessed. 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 normal ranges for fetal biometry presented in this section were established from cross sectional data on 1040 singleton pregnancies at 14 40 weeks of. The use of the biparietal diameter bpd.

It increases from about 2 4 cm at 13 weeks to about 9 5 cm at term. Since all of these measurements are strongly related to gestational age it is not usually important how they are combined. Bpd together with head circumference hc abdominal circumference ac and femur length fl are computed to produce an estimate of fetal weight. Biparietal diameter bpd this is the diameter between the two sides of the head and is measured after 13 weeks.

Normal deviations are shown in brackets in the chart below. In the second trimester this may be extrapolated to an estimate of gestational age and an estimated due date edd. Ultrasound obstet gynecol 1994 4 34 48 the patients fulfilled the following. Biparietal diameter bpd is one of the basic biometric parameters used to assess fetal size.

Different babies of the same weight can have different head size therefore dating in the later part of pregnancy is generally considered unreliable.