Occipital frontal diameter:Len:Pt:Head^Fetus:Qn:US.estimated from Chitty 1994
occipital frontal diameter:len:pt:head^fetus:qn:us.estimated from chitty 1994
Occipital frontal diameter estimated from gestational age by method of Chitty 1994 (US)
occipital frontal diameter estimated from gestational age by method of chitty 1994 (us)