Download PDF
Am J Perinatol 2024; 41(S 01): e3147-e3156
DOI: 10.1055/a-2196-6835
Original Article

Selection of Standards for Sonographic Fetal Femur Length by Use of z-Scores

C Andrew Combs
1   Pediatrix Center for Research, Education, Quality & Safety, Pediatrix Medical Group, Sunrise, Florida
2   Obstetrix of San Jose, Campbell, California
,
Amber Del Rosario
2   Obstetrix of San Jose, Campbell, California
,
Olaide Ashimi Balogun
3   Obstetrix Maternal-Fetal Medicine Specialists, Houston, Texas
,
Zachary S. Bowman
4   Perinatal Associates of Sacramento, Sacramento, California
,
Sushma Amara
5   Eastside Maternal-Fetal Medicine Specialists, Bellevue, Washington
› Author Affiliations
› Further Information
Also available at
    Permissions and Reprints

Corrected by:

Erratum: Selection of Standards for Sonographic Fetal Femur Length by Use of z-ScoresAm J Perinatol 2024; 41(S 01): e3426-e3426
DOI: 10.1055/s-0044-1792137

Abstract

Objectives This study aimed to evaluate which of four established norms should be used for sonographic assessment of fetal femur length (FL).

Study Design Cross-sectional study using pooled data from four maternal–fetal medicine practices. Inclusion criteria were singleton fetus, gestational age (GA) 220/7 to 396/7 weeks, biometry measured, and fetal cardiac activity present. Four norms of FL were studied: Hadlock et al, the INTERGROWTH-21st Project (IG-21st), the World Health Organization Fetal Growth Curves (WHO), and the National Institutes of Child Health and Human Development Fetal Growth Studies, unified standard (NICHD-U). The fit of our FL measurements to each norm was assessed by these criteria: mean z-score close to 0, standard deviation (SD) of z close to 1, Kolmogorov–Smirnov D-statistic close to zero, Youden J-statistic close to 1, approximately 5% of exams <5th percentile, and approximately 5% of exams >95th percentile.

Results In 26,177 ultrasound exams, our FL measurements had the best fit to the WHO standard (mean z-score 0.15, SD of z 1.02, D-statistic <0.01, J-statistic 0.95, 3.4% of exams <5th percentile, 7.0% of exams >95th percentile). The mean of the IG-21st standard was smaller than the other norms and smaller than our measurements, resulting in underdiagnosis of short FL. The mean of the Hadlock reference was larger than the other norms and larger than our measurements, resulting in overdiagnosis of short FL. The SD of the NICHD-U standard was larger than the other norms and larger than our observations, resulting in underdiagnosis of both short and long FL. Restricting the analysis to a subgroup of 7,144 low-risk patients without risk factors for large- or small-for- GA produced similar results.

Conclusion Of the norms studied, the WHO standard is likely best for diagnosis of abnormal FL.

Key Points

  • There are >30 norms for fetal FL.

  • It is unknown which norm should be used.

  • Our data fit the World Health Organization standard better than the other norms.

Keywords

fetal biometry - fetal Down syndrome - fetal growth restriction - fetal skeletal dysplasia - growth references - growth standards

Supplementary Material



Publication History

Received: 27 September 2023

Accepted: 19 October 2023

Accepted Manuscript online:
23 October 2023

Article published online:
16 November 2023

© 2023. Thieme. All rights reserved.

Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA

 

  • References

  • 1 AIUM-ACR-ACOG-SMFM-SRU practice parameter for the performance of standard diagnostic obstetric ultrasound examinations. J Ultrasound Med 2018; 37 (11) E13-E24
    PubMedSearch in Google Scholar
  • 2 Salomon LJ, Alfirevic Z, Da Silva Costa F. et al; Clinical Standards Committee. ISUOG Practice Guidelines: ultrasound assessment of fetal biometry and growth. Ultrasound Obstet Gynecol 2019; 53 (06) 715-723
    CrossrefPubMedSearch in Google Scholar
  • 3 Friebe-Hoffmann U, Dobravsky L, Friedl TWP. et al. The femur too short? 1373 fetuses with short femur during second-trimester screening. Arch Gynecol Obstet 2022; 306 (04) 1037-1044
    CrossrefPubMedSearch in Google Scholar
  • 4 Weisz B, David AL, Chitty L. et al. Association of isolated short femur in the mid-trimester fetus with perinatal outcome. Ultrasound Obstet Gynecol 2008; 31 (05) 512-516
    CrossrefPubMedSearch in Google Scholar
  • 5 Morales-Roselló J, Peralta Llorens N. Outcome of fetuses with diagnosis of isolated short femur in the second half of pregnancy. ISRN Obstet Gynecol 2012; 2012: 268218
    CrossrefPubMedSearch in Google Scholar
  • 6 Papageorghiou AT, Fratelli N, Leslie K, Bhide A, Thilaganathan B. Outcome of fetuses with antenatally diagnosed short femur. Ultrasound Obstet Gynecol 2008; 31 (05) 507-511
    CrossrefPubMedSearch in Google Scholar
  • 7 Schramm T, Gloning KP, Minderer S. et al. Prenatal sonographic diagnosis of skeletal dysplasias. Ultrasound Obstet Gynecol 2009; 34 (02) 160-170
    CrossrefPubMedSearch in Google Scholar
  • 8 Agathokleous M, Chaveeva P, Poon LCY, Kosinski P, Nicolaides KH. Meta-analysis of second-trimester markers for trisomy 21. Ultrasound Obstet Gynecol 2013; 41 (03) 247-261
    CrossrefPubMedSearch in Google Scholar
  • 9 Mone F, Mellis R, Gabriel H. et al. Should we offer prenatal exome sequencing for intrauterine growth restriction or short long bones? A systematic review and meta-analysis. Am J Obstet Gynecol 2023; 228 (04) 409-417.e4
    CrossrefPubMedSearch in Google Scholar
  • 10 Hutcheon JA, Liauw J. Should fetal growth charts be references or standards?. Epidemiology 2021; 32 (01) 14-17
    CrossrefPubMedSearch in Google Scholar
  • 11 Hadlock FP, Deter RL, Harrist RB, Park SK. Estimating fetal age: computer-assisted analysis of multiple fetal growth parameters. Radiology 1984; 152 (02) 497-501
    CrossrefPubMedSearch in Google Scholar
  • 12 Papageorghiou AT, Ohuma EO, Altman DG. et al; International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project. Lancet 2014; 384 (9946) 869-879
    CrossrefPubMedSearch in Google Scholar
  • 13 Kiserud T, Piaggio G, Carroli G. et al. The World Health Organization Fetal Growth Charts: a multinational longitudinal study of ultrasound biometric measurements and estimated fetal weight. PLoS Med 2017; 14 (01) e1002220
    CrossrefPubMedSearch in Google Scholar
  • 14 Grantz KL, Grewal J, Kim S. et al. Unified standard for fetal growth: the NICHD Fetal Growth Studies. Am J Obstet Gynecol 2022; 226: 576-587
    CrossrefPubMedSearch in Google Scholar
  • 15 O'Brien GD, Queenan JT. Growth of the ultrasound fetal femur length during normal pregnancy. Part I. Am J Obstet Gynecol 1981; 141 (07) 833-837
    CrossrefPubMedSearch in Google Scholar
  • 16 Jeanty P, Cousaert E, Cantraine F, Hobbins JC, Tack B, Struyven J. A longitudinal study of fetal limb growth. Am J Perinatol 1984; 1 (02) 136-144
    Thieme ConnectPubMedSearch in Google Scholar
  • 17 Warda AH, Deter RL, Rossavik IK, Carpenter RJ, Hadlock FP. Fetal femur length: a critical reevaluation of the relationship to menstrual age. Obstet Gynecol 1985; 66 (01) 69-75
    PubMedSearch in Google Scholar
  • 18 Hansmann M, Hackelöer BJ, Staudach A. Ultrasound Diagnosis in Obstetrics and Gynecology. Berlin, Heidelberg, New York, Tokyo: Springer;; 1986
    CrossrefSearch in Google Scholar
  • 19 Nicolini U, Todros T, Ferrazzi E. et al. Curve trasversali dell'accrescimento fetale. Studio multicentrico. Minerva Ginecol 1986; 38 (11) 873-887
    PubMedSearch in Google Scholar
  • 20 Chitty LS, Altman DG, Henderson A, Campbell S. Charts of fetal size: 4. Femur length. Br J Obstet Gynaecol 1994; 101 (02) 132-135
    CrossrefPubMedSearch in Google Scholar
  • 21 Snijders RJ, Nicolaides KH. Fetal biometry at 14-40 weeks' gestation. Ultrasound Obstet Gynecol 1994; 4 (01) 34-48
    CrossrefPubMedSearch in Google Scholar
  • 22 Shinozuka N, Masuda H, Kagawa H, Taketani Y. Standard values of ultrasonographic fetal biometry. Jpn J Med Ultrasonics 1996; 23: 877-888
    PubMedSearch in Google Scholar
  • 23 Weldner BM. Ultraljud: Obstetrik Och Gynekologi. Lund: Studentlitteratur; 1998
    Search in Google Scholar
  • 24 Lai FM, Yeo GSH. Reference charts of foetal biometry in Asians. Singapore Med J 1995; 36 (06) 628-636
    PubMedSearch in Google Scholar
  • 25 Merz E, Wellek S. Das normale fetale Wachstumsprofil–ein einheitliches Modell zur Berechnung von Normkurven für die gängigen Kopf- und Abdomen-parameter sowie die grossen Extremitätenknochen. Ultraschall Med 1996; 17 (04) 153-162
    Thieme ConnectPubMedSearch in Google Scholar
  • 26 Lessoway VA, Schulzer M, Wittmann BK, Gagnon FA, Wilson RD. Ultrasound fetal biometry charts for a North American Caucasian population. J Clin Ultrasound 1998; 26 (09) 433-453
    CrossrefPubMedSearch in Google Scholar
  • 27 Guihard-Costa AM, Thiebaugeorges O, Droullé P. Biométrie foetale: standards de croissance et croissance individuelle. In: Encyclopédie Médico-Chirurgicale. Paris: Elsevier; 1999
    Search in Google Scholar
  • 28 Kurmanavicius J, Wright EM, Royston P. et al. Fetal ultrasound biometry: 2. Abdomen and femur length reference values. Br J Obstet Gynaecol 1999; 106 (02) 136-143
    CrossrefPubMedSearch in Google Scholar
  • 29 Créquat J, Duyme M, Brodaty G. Biométrie 2000. Tables de croissance foetale par le Collège français d'échographie foetale (CFEF) et l'Inserm U 155. Gynécol Obstét Fertil 2000; 28 (06) 435-445
    PubMedSearch in Google Scholar
  • 30 Titapant V, Siwadune T, Boriboonhirunsarn D, Sunsaneevithayakul P, Swasdimongkol S, Sutanthavibul A. Charts of Thai fetal biometries: 3. Femur length. J Med Assoc Thai 2000; 83 (03) 299-306
    PubMedSearch in Google Scholar
  • 31 Japan Society of Ultrasound in Medicine. Ultrasound fetal measurement standardization and Japanese standard. J Med Ultrason 2003; 30: 3
    PubMedSearch in Google Scholar
  • 32 Johnsen SL, Rasmussen S, Sollien R, Kiserud T. Fetal age assessment based on femur length at 10-25 weeks of gestation, and reference ranges for femur length to head circumference ratios. Acta Obstet Gynecol Scand 2005; 84 (08) 725-733
    CrossrefPubMedSearch in Google Scholar
  • 33 Schluter PJ, Pritchard G, Gill MA. Ultrasonic fetal size measurements in Brisbane, Australia. Australas Radiol 2004; 48 (04) 480-486
    CrossrefPubMedSearch in Google Scholar
  • 34 Paladini D, Rustico M, Viora E. et al. Fetal size charts for the Italian population. Normative curves of head, abdomen and long bones. Prenat Diagn 2005; 25 (06) 456-464
    CrossrefPubMedSearch in Google Scholar
  • 35 Johnsen SL, Wilsgaard T, Rasmussen S, Sollien R, Kiserud T. Longitudinal reference charts for growth of the fetal head, abdomen and femur. Eur J Obstet Gynecol Reprod Biol 2006; 127 (02) 172-185
    CrossrefPubMedSearch in Google Scholar
  • 36 Salomon LJ, Duyme M, Créquat J. et al. French fetal biometry: reference equations and comparison with other charts. Ultrasound Obstet Gynecol 2006; 28 (02) 193-198
    CrossrefPubMedSearch in Google Scholar
  • 37 Leung TN, Pang MW, Daljit SS. et al. Fetal biometry in ethnic Chinese: biparietal diameter, head circumference, abdominal circumference and femur length. Ultrasound Obstet Gynecol 2008; 31 (03) 321-327
    CrossrefPubMedSearch in Google Scholar
  • 38 Verburg BO, Steegers EAP, De Ridder M. et al. New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population-based cohort study. Ultrasound Obstet Gynecol 2008; 31 (04) 388-396
    CrossrefPubMedSearch in Google Scholar
  • 39 Daniel-Spiegel E, Weiner E, Yarom I. et al. Establishment of fetal biometric charts using quantile regression analysis. J Ultrasound Med 2013; 32 (01) 23-33
    CrossrefPubMedSearch in Google Scholar
  • 40 Buck Louis GM, Grewal J, Albert PS. et al. Racial/ethnic standards for fetal growth: the NICHD Fetal Growth Studies. Am J Obstet Gynecol 2015; 213 (04) 449.e1-449.e41
    CrossrefPubMedSearch in Google Scholar
  • 41 Stirrup OT, Khalil A, D'Antonio F, Thilaganathan B. Southwest Thames Obstetric Research Collaborative (STORK). Fetal growth reference ranges in twin pregnancy: analysis of the Southwest Thames Obstetric Research Collaborative (STORK) multiple pregnancy cohort. Ultrasound Obstet Gynecol 2015; 45 (03) 301-307
    CrossrefPubMedSearch in Google Scholar
  • 42 Salomon LJ, Bernard JP, Duyme M, Buvat I, Ville Y. The impact of choice of reference charts and equations on the assessment of fetal biometry. Ultrasound Obstet Gynecol 2005; 25 (06) 559-565
    CrossrefPubMedSearch in Google Scholar
  • 43 American College of Obstetricians and Gynecologists. ACOG Committee Opinion 700: Methods for estimating the due date. Obstet Gynecol 2017; 129 (05) e150-e154
    CrossrefPubMedSearch in Google Scholar
  • 44 Combs CA, Castillo R, Webb GW, Del Rosario A. Impact of adding abdominal circumference to the definition of fetal growth restriction. Am J Obstet Gynecol MFM 2021; 3 (04) 100382
    CrossrefPubMedSearch in Google Scholar
  • 45 Combs CA, Castillo R, Kline C. et al. Choice of standards for sonographic fetal abdominal circumference percentile. Am J Obstet Gynecol MFM 2022; 4 (06) 100732
    CrossrefPubMedSearch in Google Scholar
  • 46 Combs CA, Rosario AD, Balogun OA, Bowman ZS, Amara S. Selection of standards for sonographic fetal head circumference by use of z-scores. Am J Perinatol 2023;
    CrossrefPubMedSearch in Google Scholar
  • 47 Sananes N, Guigue V, Kohler M. et al. Use of Z-scores to select a fetal biometric reference curve. Ultrasound Obstet Gynecol 2009; 34 (04) 404-409
    CrossrefPubMedSearch in Google Scholar
  • 48 Bihoun B, Zango SH, Traoré-Coulibaly M. et al. Fetal biometry assessment with Intergrowth 21st's and Salomon's equations in rural Burkina Faso. BMC Pregnancy Childbirth 2020; 20 (01) 492
    CrossrefPubMedSearch in Google Scholar
  • 49 Villar J, Papageorghiou AT, Pang R. et al; International Fetal and Newborn Growth Consortium for the 21st Century (INTERGROWTH-21st). The likeness of fetal growth and newborn size across non-isolated populations in the INTERGROWTH-21st Project: the Fetal Growth Longitudinal Study and Newborn Cross-Sectional Study. Lancet Diabetes Endocrinol 2014; 2 (10) 781-792
    CrossrefPubMedSearch in Google Scholar