the following formulas are recommended for weeks 9 to 20 of pregnancy , where w = weeks and f , l , and a are the foot , leg , and arm measurements in centimeters : w = 4.5261 + 11.937 ( f ) - 4.4895 ( f2 ) + 0.71583 ( f3 ) ;
C0016504
foot
C0023216
leg