[Ultrasonic biometry of the fetal crown-rump length between 7 and 20 weeks gestation (author's transl)]
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In 370 examinations on 258 patients with known gestational age crown-rump length (CRL) of the fetus was determined by sonar between 7 and 20 weeks. From the results the mean and "2 SD" limits of CRL were derived by means of a non linear regression analysis. The measurements were further analysed to determine gestational age for a given CRL. Besides a velocity curve of CRL growth was calculated. It showed a maximum of 1.8 mm per day at 14 weeks. It was confirmated that sonar measurements of crown-rump length are very useful to estimate maturity of the fetus. The accuracy was found to be best in early measurements (+/-6 days at 7 weeks -+/-11 days at 20 weeks). In regard to clinical decisions reading errors have to be taken into consideration. To avoid them control examinations should be carried out.
In 370 examinations on 258 patients with known gestational age crown-rump length (CRL) of the fetus was determined by sonar between 7 and 20 weeks. From the results the mean and "2 SD" limits of CRL were derived by means of a non linear regression analysis. The measurements were further analysed to determine gestational age for a given CRL. Besides a velocity curve of CRL growth was calculated. It showed a maximum of 1.8 mm per day at 14 weeks. It was confirmated that sonar measurements of crown-rump length are very useful to estimate maturity of the fetus. The accuracy was found to be best in early measurements (+/-6 days at 7 weeks -+/-11 days at 20 weeks). In regard to clinical decisions reading errors have to be taken into consideration. To avoid them control examinations should be carried out.
