These calculators were compiled with care and using published formulae (see references)
The results should be used as examples of gestational age determination and fetal size and growth calculation and only for the gestational age ranges indicated in the respective publications. Before using any calculator for clinical decisions, the local population should be verified against the respective normal ranges.
ISUOG does not assume responsibility for the results obtained with these calculators and does not encourage to use this calculator for clinical decisions. By using these calculators you agree with these terms.
References
Formulae and data used for construction of the ISUOG Biometry Calculators
Boris Tutschek for ISUOG.org, release date April 2018
| Purpose | Publication | Range (postmenstrual weeks) |
| Dating by CRL | Papageorghiou et al. UOG 2014 | 9-13 weeks |
| Dating by BPD | Selbing et al. Acta Obstet Gynecol Scand 1985 |
11-24 weeks |
| BPD, HC, AC, FL | Papageorghiou et al. Lancet 2014 | 14-42 weeks |
| EFW calculation | Hadlock et al. AJOG 1985 | |
| EFW centile calculation | derived from Yudkin et al. Early Hum Dev 1987 |
24-42 weeks |
| Thoracic circumference | Laudy et al. UOG 2000 | 20-40 weeks |
| Tibia, fibula, humerus, ulna, radius | Chitty et al. BJOG 1994 | 12-42 weeks |