title: The crown-rump length in early human pregnancy: a reappraisal.
abstract: The crown-rump length (CRL) was measured by means of transvaginal sonography in 41 pregnancies resulting from in-vitro fertilization (IVF). The embryonic CRL could be determined as early as 25 days after follicle aspiration. A reference chart was constructed relating the CRL to the number of days following follicle aspiration. Comparison with the CRL chart by Robinson & Fleming (1975) currently in use revealed that transvaginal sonography allows earlier and more accurate measurement of embryonic CRL.
authors.affiliation: Department of VEVO/IVF, Academisch Ziekenhuis Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: R
authors.initials: R
authors.lastname: Schats
authors.forename: H C
authors.initials: HC
authors.lastname: Van Os
authors.forename: C A
authors.initials: CA
authors.lastname: Jansen
authors.forename: J W
authors.initials: JW
authors.lastname: Wladimiroff
mesh_terms: D000328:Adult; D000886:Anthropometry; D005314:Embryonic and Fetal Development; D005260:Female; D005307:Fertilization in Vitro; D005333:Fetus / Q000033:anatomy & histology*; D006801:Humans; D015588:Observer Variation; D011247:Pregnancy; D012016:Reference Values; D013997:Time Factors; D016216:Ultrasonography, Prenatal / Q000379:methods / Q000592:standards*; D014621:Vagina