Napolitano R, Dhami J, Ohuma EO, Ioannou C, Conde-Agudelo A, Kennedy SH et al. Pregnancy dating by fetal crown-rump length: a systematic review of charts. BJOG 2014, 121(5):556-565.



Papageorghiou AT, Kennedy SH, Salomon LJ, Ohuma EO, Cheikh Ismail L, Barros FC et al. International standards for early fetal size and pregnancy dating based on ultrasound measurement of crown-rump length in the first trimester of pregnancy. Ultrasound Obstet Gynecol 2014, 44(6):641-48.

doi: 10.1002/uog.13448


Tables & Graphs


Click here to download the entire package;




Z-Scores (Standard deviations)

Crown-Rump Length



Tables and charts will also be made available in French, Italian, Portuguese and Spanish.


Calculators & Apps



Excel-based Gestational Age Assessment Calculator

Training & Resources


Study Protocol

Correct measurement of CRL and standardisation manual