Interventricular septal thickness of Thai fetuses: at 32 to 35 weeks' gestation

To establish the normal value of fetal InterVentricular Septal Thickness (IVST) from 32 to 35 weeks' gestation in Thai fetuses.

Thai pregnant women with normal fetuses were recruited for prenatal 2-dimensional M-mode echocardiographic measurements of fetal IVST at 32 to 35 weeks' gestation. All had a confirmed gestational age, normal structural scanning and negative diabetic screening at 24 to 28 weeks 'gestation. The IVST was measured from the 4-chamber view during diastole and systole. The 5th, 50th and 95th percentile of the IVST during Diastole (IVSD) and the IVST during Systole (IVSS) were demonstrated The relationship between the IVSD and IVSS and gestational age were determined

A total of 410 measurements were obtained. The normal values of the IVSD and IVSS according to gestational age were presented as 5th, 50th and 95th percentile ranks. The correlation coefficients (r) between the IVSD and IVSS and gestational age were 0.11 and 0.12, respectively. The IVSD and IVSS were not statistically different with advancing gestation. The 95th, percentile of the IVSD was 4.51 millimeters (mm) (range = 4.26 to 4.74 mm) and IVSS was 6.23 mm (range = 5.96 to 6.68 mm). The intraobserver variability was 7.6%.

The normal values of fetal IVSD and IVSS in a Thai population from 32 to 35 weeks' gestation were established. This could be used as a baseline data in detecting the asymmetrical septal hypertrophy during fetal life.