Perimeter:Len:Pt:Head^Fetus:Qn:US.derived from OFD&O-O TD
perimeter:len:pt:head^fetus:qn:us.derived from ofd&o-o td
Fetal Head Circumference derived from occipital-frontal diameter and outer-outer transaxial diameter (US)
fetal head circumference derived from occipital-frontal diameter and outer-outer transaxial diameter (us)