RESUMO
The crown-rump length(CRL) remains the most accurate parameter used for gestational dating. We aimed to establish the early fetal growth with CRL range in Korean women. The CRL of 48 singleton pregnancies which resulted from in vitro fertilization and e mbryo transfer(IVF-ET) at SNUH were assessed two to six times in the first trimester by trans-vaginal ultrasonography. All women included in this study went on to deliver norma l infa-nts at 37 completed weeks or after weighing over 2.5 kg. And we also studied the r elationship between CRL(in millimeters) and gestational age(in days), and found that the fo llowing second-order polynomial might be applied either to expect CRL using the menstr ual gestational age, or to estimate gestational age using measured CRL(r2=0.980, p=0.000 1). CRL=0.0175(GA)2-1.049(GA)+19.17 GA=7.5593(CRL-3.45)1/2+29.97 Finally we compared our data with some of published articles which assessed CRL in spontaneous and induced pregnancies. In conclusion, this study establish the early fetal growth with CRL range in Korean women on the basis of exact ovulation timing using high resolution transvaginal ultrasonography. And these data will be of great use in the evaluation of fetal growth in the first trimester.