Ultrasound dating at 12–14 weeks of gestation. A prospective cross‐validation of established dating formulae in <i>in‐vitro</i> fertilized pregnancies

Abstract

We have identified three BPD formulae that are suitable for dating at 12-14 weeks of gestation. They are superior to all 21 CRL formulae tested here, because their random measurement errors were much smaller than those of the three best CRL formulae. The small systematic negative measurement errors associated with the BPD formulae are likely to be clinically unimportant.