Transcerebellar diameter: an effective tool in predicting gestational age in normal and IUGR pregnancy

Background: Gestational age is the common term used during pregnancy to describe how far advanced is the pregnancy. In the second and third trimesters, estimation of gestational age is accomplished by measuring the biparietal diameter, head circumference, abdominal circumference, and femur length. The transverse cerebellar diameter (TCD) may serve as a reliable predictor of gestational age (GA) of the fetus and a standard against which aberrations in other fetal parameters can be compared.Methods: The study was conducted in the tertiary care teaching hospital from July 2016 to March 2017. 200 pregnant women of gestational age 15-40 weeks of pregnancy referred from Dept of Obs and Gynae for antenatal scan comprised our study sample.Results: Age of women ranged from 18 to 43 years with maximum number of patients aged 26-30 years. Maximum cases with clinical suspicion for IUGR were in gestational age >36-40 weeks (50%). Evaluation of difference in actual and estimated gestational age between normal and actual gestational age showed that for normal pregnancy as well as in IUGR pregnancies mean difference between estimated and actual gestational age was minimum in TCD followed by other established parameters.Conclusions: TCD being a stable parameter irrespective of growth status of fetus, provides a basis for its usefulness as a ratio to predict IUGR and other perainatal outcomes as used in several studies. Thus, despite not being a direct marker for IUGR it can serve as a surrogate marker for detection of IUGR and another adverse perinatal outcome