Fetal EchoExperimental

Fetal Z scores

Z = [ ln(measured) - (b0 + b1 x ln(x)) ] / RMSE
x = gestational age [weeks], or femur length

Schneider 2005 sites: measurement in cm, FL in cm (page converts from mm)
Pasquini 2007 sites (isthmus, duct): measurement in mm, FL in mm

• Schneider C, McCrindle BW, Carvalho JS, Hornberger LK, McCarthy KP, Daubeney PEF. Development of Z-scores for fetal cardiac dimensions from echocardiography. Ultrasound Obstet Gynecol 2005;26(6):599-605. doi:10.1002/uog.2597. Abstract: 130 fetuses, 15–39 weeks, 17 dimensions, natural-log regressions on FL, BPD or GA.
• Pasquini L, Mellander M, Seale A, et al. Z-scores of the fetal aortic isthmus and duct: an aid to assessing arch hypoplasia. Ultrasound Obstet Gynecol 2007;29(6):628-633. doi:10.1002/uog.4021. Abstract: 221 fetuses, 18–37 weeks; the Z formula above is quoted from it.
• [unverified against the primary papers] The intercepts, slopes and RMSE values were not retrieved from the papers (full texts not accessible). They are transcribed from the ParameterZ implementation by Dan Dyar (assets.parameterz.com/js/Fetal04.js and Fetal_FL.js, MIT licence, © 2009 Dan Dyar) and every site was cross-checked against the ParameterZ fetal web app at 24.0 weeks and FL 45 mm (all Z scores and means agree to 0.01). Treat these as a published implementation, not the source tables. BPD-based equations are not included.
• Femur-length range: the FL range of the source data was not verified; the page accepts 10–76 mm (the ParameterZ input limits). Z scores beyond ±6 trigger a units check.

Cardiovascular Profile Score (Huhta)

Five categories, 2 points each (10 = normal):
hydrops, venous Doppler (UV, DV), heart size (heart/chest area),
cardiac function, arterial Doppler (umbilical artery)

• Huhta JC. Guidelines for the evaluation of heart failure in the fetus with or without hydrops. Pediatr Cardiol 2004;25(3):274-286. doi:10.1007/s00246-003-0591-3.
• Falkensammer CB, Paul J, Huhta JC. Fetal congestive heart failure: correlation of Tei-index and cardiovascular-score. J Perinat Med 2001;29(5):390-398. doi:10.1515/JPM.2001.055. Abstract: “2 points each for absence of hydrops, normal venous Doppler, heart function, arterial Doppler, and heart size, and 10/10 = normal”.
• Hofstaetter C, Hansmann M, Eik-Nes SH, Huhta JC, Luther SL. A cardiovascular profile score in the surveillance of fetal hydrops. J Matern Fetal Neonatal Med 2006;19(7):407-413. doi:10.1080/14767050600682446. Abstract: 102 hydropic fetuses; median CVPS 6 in perinatal deaths vs 7 in survivors; umbilical venous pulsations were the best predictor of adverse outcome.
• [secondary source] The point criteria in each category are taken from two open-access reviews that reproduce the Huhta table (Diagnostics 2023, doi:10.3390/diagnostics13040779, “modified from Huhta 2004”; Diagnostics 2025, doi:10.3390/diagnostics15182303). They differ slightly: one lists TR dP/dt <400 under 0 points, and the heart-size cut points are written >0.20 and <0.35 in one and ≤35% in the other. This page counts 0.20–0.35 inclusive as 2 points and notes any value exactly on a cut point. Severity bands (mild, moderate, severe) differ between sources, so none is shown.