Fetal Echo Z-Scores: Femur Length

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This is an updated version of the fetal echo z-score calculator: Fetal cardiac z-scores and dates (LMP, EGA, EDD) are derived from fetal biometry. Also added are ratio calculations for the mitral/tricuspid valves, LV/RV, and aortic/pulmonic valves.

Based on today's date and the given femur length:

The EGA is ...;
the LMP was ...;
the EDD is ...

Site Measured Mean Range Z-Score
Left Heart (cm)
Right Heart (cm)
Isthmus & Duct (mm)


New charts for ultrasound dating of pregnancy. Altman DG, Chitty LS. Ultrasound Obstet Gynecol. 1997 Sep;10(3):174-91.

Development of Z-scores for fetal cardiac dimensions from echocardiography. Schneider C, McCrindle BW, Carvalho JS, Hornberger LK, McCarthy KP, Daubeney PE. Ultrasound Obstet Gynecol. 2005 Nov;26(6):599-605.

Z-scores of the fetal aortic isthmus and duct: an aid to assessing arch hypoplasia. Pasquini L, Mellander M, Seale A, Matsui H, Roughton M, Ho SY, Gardiner HM. Ultrasound Obstet Gynecol. 2007 Jun;29(6):628-33.

Left Ventricle to Right Ventricle Size Discrepancy in the Fetus: The Presence of Critical Congenital Heart Disease Can Be Reliably Predicted. Quartermain MD, Cohen MS, Dominguez TE, Tian Z, Donaghue DD, Rychik J. J Am Soc Echocardiogr. 2009 Oct 6. [Epub ahead of print]