Accuracy of fetal transcerebellar diameter nomogram in the prediction of gestational age in singleton gestation at the second and the third trimesters of singleton pregnancy

Abstract

ObjectiveThe present study assessed the accuracy of transcerebellar diameter (TCD) measurement in the estimation of gestational age during the second and third trimesters compared with the other fetal biometric measurements femur length (FL) and biparietal diameter (BPD). Patients and methodsThis study was carried out on 150 women with normally progressing pregnancies during the second and third trimesters, with gestational ages between 15 and 38 weeks. The criteria for inclusion in the study were singleton gestation, head presentation, absence of fetal anomalies, and no history of chronic diseases: diabetes and/or hypertension, and no history of abnormal babies, or stillbirths. All patients provided informed consent and were subjected to the following: thorough assessment of history; general and abdominal examination; and ultrasound to assess, fetal viability, BPD, FL, and TCD. Transabdominal ultrasound was performed for all participants. Fetal TCD was measured by locating the cerebellum in the posterior fossa by means of rotation of the transducer to B301 from the plane that identifies the thalamus, cavity of the septum pellucidum, third ventricle, and cisterna magna, positioning the calipers on the outer margins of the cerebellar hemispheres. ResultsThe fetuses studied had a mean FL of 56.32 ± 16.48 mm, BPD of 46.18 ± 8.71 mm, and TCD of 30.73 ± 7.01 mm. The mean actual gestational age was 16.16 ± 0.75 for TCD of 16 mm and it increased up to 37 ± 1.15 for TCD of 42 mm. ConclusionThe TCD measurement appears to be an accurate predictor of gestational age, even in the third trimester of pregnancy. It is recommended to use TCD as an important ultrasound biometric parameter in normal singleton for the prediction of gestational age.