S o n g r a m s o f 1 2 8 c h i n e s e f e t u s e s s c a n n e d between 16-20 week' gestational age, with l a s t m e n s t r u a l p e r i o d a n d a v e r a g e s o n og r a p h i c a g e c o r r e s p o n d i n g b y ± 1 0 d a y s , w e r e e v a l u a t e d r e t r o s p e c t i v e l y . T h e f e t a l f e m u r l e n g h t w a s m e a s u r e d l o n g i t u d i n a l l y u s i n g a l i n e a r p h a s e d a r r a y t r a n s d u c e r . T h e o b s e r v e d s p o n d i n g d a t a i n H a d l o c k ' s c h a r t , w h i c h i s based on a white middle class population. Res u l t s i n d i c a t e d t h a t t h e c h i n e s e f e m u r l e n g h t w a s s h o r t e r t h a n t h e h a d l o c k v a l u e s b y o . 5 6 m m . T h e a n a l y s i s o f v a r i a n c e r e v e a l e d t h a t this differency. Although the findings were statisf o r a n a d j u s t m e n t t o t h e H a d l o c k c h a r t , a sThe ultrasound measurement of the fetal femur length is considered one of the most accurate biometric measurements in determining gestational age.l I However, the femur length charts most commonly used are Hadlock's tables, which were created based on white middle class populations.2 Because of the observation and general acceptance of various height differences found between the Chinese population and the white population, a retrospective study was initiated to determine if these differences are evident in utero and if they affect accepted measurements used for prediction of gestational age.

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