Biological gestational age and its calendar assessment with ultrasound. Part 2: Biological-calendar scales for prediction of birth-date.

Abstract

Evaluation of enzymatic and sonographic assessments has been done in terms of relativity of gestational length. The principle of relativity means that it is not the calendar time but the biological one that qualifies the results of both the diagnostic procedures and treatments. The described biological-calendar scale comprises and links both the enzymatic and ultrasonographic data. The shifting of the end of the biological scale to the end of the calendar scale enables the appropriate evaluation of both the child's maturation for labor, as well as the pregnancy duration from the last menstrual period until the end of normal births range. It is why almost all ultrasound scales heretofore useful only for 50% of deliveries (as usually encompassing range of 40 weeks) have to be lengthened.