ABSTRACT

To obtain nomogram of fetal transcerebellar diameter at 16-24 weeks of gestation with known prognosis of normal pregnancies.

Transcerebellar diameter and other routine biometric measurements of 702 structural normal fetuses at 16-24 weeks of gestation were measured by transabdominal ultrasonography, prospectively. The distribution of transcerebellar diameter is established according to gestational weeks and percentiles between 16-24 weeks are calculated. Relationship between transcerebellar diameter and the other parameters were assessed by regression analysis.

Median values of transcerebellar diameter between 16-24 weeks were 16, 16, 18, 19, 20, 21, 22, 23 and 25 mm respectively. Transcerebellar diameter is linearely increased between 16-24 weeks. Significant correlation was also found between the transcerebellar diameter and gestational weeks (GH) (TCD=GH x 1,1767-3,513 (r2=0,82; p<0,001)).

The transcerebellar diameter nomogram obtained at 16-24 gestational weeks shows the same difference with the worldwide use. Our TCD nomogram is usable for ultrasound determination of gestational age for Turkish population.

Keywords: Transcerebellar diameter, Gestational age, Nomogram