Use of mathematical techniques for prognosis of large fetus weight in the third trimester of pregnancy

Abstract

Aim: Prognosis of intrauterine fetus weight in case of macrosomia in the third trimester of pregnancy in order to optimize date and method of birth.

Full Text

Methods: Ultrasonography of fetus in the third trimester of pregnancy with biparietal diameter (BD), femur length (FL), abdominal circumference (AC), transverse heart diameter at the level of four chambers (THD) measurements. Ultrasonography was performed with the use of linear array transducer 3,5 MHz from Aloka-650 and convex transducer 5 MHz. The results were processed using statistics analysis methods with the help of ECM. Construction of prognosis model was performed by linear multiple regressing analysis. Applied programmes «Statgraphics» were used for calculation. Transverse heart diameter 40 mm and greater is the diagnostic criteria of large fetus (p<0,001).

Results: With the help of regressing analysis the decisive rule of prognosis was created, making possible the evaluation of large fetus weight according to the following formula:

A=K1*BPD + K2*FL + КЗ*AC where A-biophysical criteria of large fetus prognosis in gr.;

BPD - biparietal diameter of head in mm (p<0,01),

FL - femur length in mm (p<0,05),

AC - abdominal circumference (p <0,05),

K1, K2, K3 - coefficients.

Conclusion: Decisive rule of prognosis permit to determine intrauterine fetus weight in macrosomia with high degree of reliability (R=0,98). Choosing of optimal date and method of birth decreases risk of trauma for mother and newborn.