Ultrasonic fetal transverse trunk diameter in normal northern Thai women.

ABSTRACT

Fetal transverse trunk diameter (TTD) were measured by two obstetric sonographers, using Aloka model SSD 630 and 650. The measurements were performed on 1,009 occasions in 235 women during normal pregnancies between the 14th and 40th weeks (age range 17-37 years) (4.5 measurements per pregnancy, on average). The relation between TTD and menstrual age was determined and mathematical modeling of the data demonstrated that the linear quadratic function was optimal (r2 = 0.973). The most fitted regression equation was obtained by regression analysis. 1.) TTD = -2.69055 + 0.38326 G.A - 0.00140137 GA2 2.) GA = 7.222585 + 2.82632 TTD + 0.02605 TTD2. Interestingly, TTD value for each gestational week in this study is not so different from that of the European data. Predicted TTD values for a given gestational week were determined and presented in tabular form. The values from this study may be important baseline data for evaluation of fetal growth in our population.