Cerebellar Diameter Research Articles

A contrastive study of cerebellum development in very premature and full-term infants

ObjectiveTo compare the difference between full-term infants and very low birth weight (VLBW) premature infants at term equivalent for cerebellum development by cranial ultrasound in order to provide reference for monitoring the extrauterine development of cerebellum in VLBW premature infants. MethodsWith a study of 88 cases which were VLBW premature infants with gestational age less than 32 weeks were examined by cranial ultrasound at 40 weeks of corrected gestational age and 65 full-term infants at 40 weeks of gestational age were examined by cranial ultrasound at the day of birth. Comparing the difference between the two groupsfor transverse cerebellar diameter, cerebellar vermis height, anteroposterior vermis diameter, cerebellar vermis circumference and cerebellar vermis area. The difference of the above cerebellar indexes between 32 extremely premature infants with gestational age of less than 28 weeks and 56 premature infants with gestational age of greater than or equal to 28 weeks were compared as well. ResultsCompared to the premature infants at term equivalent age group and full-term infants group, the transverse cerebellar diameter in the premature infants at term equivalent age group was smaller than that in the full-term infants group (P < 0.05). There was no statistically significant difference between the two groups in the cerebellar vermis height, anteroposterior vermis diameter, cerebellar vermis circumference and cerebellar vermis area (P > 0.05). The transverse cerebellar diameter in the extremely premature infants group was smaller than that in VLBW premature infants group (P < 0.05). The difference between the two groups was also not statistically significant in the cerebellar vermis height, anteroposterior vermis diameter, cerebellar vermis circumference and cerebellar vermis area (P > 0.05). ConclusionThe growth of midline structure of the cerebellum was preserved in the premature infants at term equivalent age without supratentorial brain injury probably, and the growth of lateral structure of the cerebellum will be decreased, which is most vulnerable to insult following the factor of premature birth.

Transverse Cerebellar Diameter as an Independent Predictor of Gestational Age in Normal and IUGR Pregnancies

Transverse Cerebellar Diameter as an Independent Predictor of Gestational Age in Normal and IUGR Pregnancies

A Closer Look at a Small Brain: Transnuchal Ultrasound Facilitates High-Resolution Imaging of the Cerebellum in Preterm Infants.

Very preterm infants are at risk for cerebellar injury and impaired cerebellar growth with adverse neurodevelopmental outcome. Ultrasound through the mastoid fontanel (MF) with a curved-array or sector probe is the most established method for the sonographic examination of the cerebellum. The goal of our study was to examine the validity of transnuchal ultrasound through the foramen occipitale magnum (FOM) with a linear probe for monitoring postnatal cerebellar growth. Retrospective analysis of routine ultrasound scans through FOM and MF in 105 preterm infants born between 23 and 36 weeks of gestation with a birthweight of less than 1500 g. Diameters of the cerebellar hemispheres obtained through the two acoustic windows mastoid fontanel and foramen occipitale magnum showed high correlations (r's = 0.981 and 0.983, p's < 0.001). Corrected gestational age was significantly associated with transverse cerebellar diameter (TCD) on the first scan (r = 0.908, p < 0.001) as well as postnatal cerebellar growth (r = 0.920, p < 0.001). Postnatal growth was slightly decreased resulting in cerebellar growth restriction on serial scans. Both associations exceeded the calculated ratio of TCD to head circumference (r = 0.657, p < 0.001) and TCD to biparietal diameter with gestational age (r = 0.705, p < 0.001). Transnuchal ultrasound is feasible for examination of the preterm cerebellum and improves image quality compared to scans through the MF with higher resolution at a very short distance. Monitoring cerebellar growth during early postnatal life via transnuchal ultrasound can help to identify children at high risk for neurodevelopmental impairment.

Comparison of Estimation of Gestational Age by Transverse Cerebellar Diameter with Biparietal Diameter in Third Trimester of Pregnancy

Comparison of Estimation of Gestational Age by Transverse Cerebellar Diameter with Biparietal Diameter in Third Trimester of Pregnancy

English

English

Accuracy of Fetal Transcerebellar Diameter in the Prediction of Gestational Age in Singleton Pregnancy at the Second and the Third Trimesters

Background: Gestational age (GA) is an important parameter in obstetrics for management of pregnancy and evaluating fetal development. High incidence of perinatal mortality has been noted in patients whose accurate gestational age is not known. Objective: The aim of this study was to evaluate whether trans-cerebellar diameter (TCD) in singleton gestations can serve as a reliable predictor of gestational age (GA) in fetuses in the second and third trimester between 14-40 weeks of pregnancy in women attending the clinic for routine ultrasound examination. Patients and methods: This prospective study was carried out at the antenatal outpatient clinic at Al-Zahraa university Hospital and El-Sahel Teaching Hospital. This study was hold one thousand of pregnant women attending the outpatient clinic for routine ultrasound examination during second and third trimester between 14-40 weeks of pregnancy in a period from 1 December 2016 to March 2019. Patients and methods: This prospective study included a total of one thousand of pregnant women, attending at Antenatal Outpatient Clinic, Al-Zahraa University Hospital and El-Sahel Teaching Hospital. The accuracy of the transverse Cerebellar Diameter (TCD) in the prediction of gestational age (GA) in fetuses in the second and third trimester between 14-40 weeks of pregnancy was assessed. This study was conducted between December 2016 to March 2019 Results: According to accuracy of measured gestational age according to measured parameters in relation to actual gestational age (accuracy within 2 weeks), TCD had the highest accuracy (98.7%) than other parameters in early second trimester. Accuracy of TCD in late second trimester was 91.6% and 82% in early third trimester while in late third trimester TCD had the lowest accuracy (68.1%). Conclusion: TCD is an accurate parameter in estimation of gestational age as its values are in close relation with that of GA by LMP. TCD is a better predictor of the gestational age when compared to other parameters especially between (14-22) weeks.

Accuracy of Fetal Transcerebellar Diameter in the Prediction of Gestational Age in Singleton Pregnancy at the Second and the Third Trimesters

Background: Gestational age (GA) is an important parameter in obstetrics for management of pregnancy and evaluating fetal development. High incidence of perinatal mortality has been noted in patients whose accurate gestational age is not known. Objective: The aim of this study was to evaluate whether trans-cerebellar diameter (TCD) in singleton gestations can serve as a reliable predictor of gestational age (GA) in fetuses in the second and third trimester between 14-40 weeks of pregnancy in women attending the clinic for routine ultrasound examination. Patients and methods: This prospective study was carried out at the antenatal outpatient clinic at Al-Zahraa university Hospital and El-Sahel Teaching Hospital. This study was hold one thousand of pregnant women attending the outpatient clinic for routine ultrasound examination during second and third trimester between 14-40 weeks of pregnancy in a period from 1 December 2016 to March 2019. Patients and methods: This prospective study included a total of one thousand of pregnant women, attending at Antenatal Outpatient Clinic, Al-Zahraa University Hospital and El-Sahel Teaching Hospital. The accuracy of the transverse Cerebellar Diameter (TCD) in the prediction of gestational age (GA) in fetuses in the second and third trimester between 14-40 weeks of pregnancy was assessed. This study was conducted between December 2016 to March 2019 Results: According to accuracy of measured gestational age according to measured parameters in relation to actual gestational age (accuracy within 2 weeks), TCD had the highest accuracy (98.7%) than other parameters in early second trimester. Accuracy of TCD in late second trimester was 91.6% and 82% in early third trimester while in late third trimester TCD had the lowest accuracy (68.1%). Conclusion: TCD is an accurate parameter in estimation of gestational age as its values are in close relation with that of GA by LMP. TCD is a better predictor of the gestational age when compared to other parameters especially between (14-22) weeks.

EP07.10: Agreement between fetal brain ultrasonography and magnetic resonance imaging in measurements of the corpus callosum and transverse cerebellar diameter

EP07.10: Agreement between fetal brain ultrasonography and magnetic resonance imaging in measurements of the corpus callosum and transverse cerebellar diameter

Fetal and perinatal outcome associated with small cerebellar diameter based on second- or third-trimester ultrasonography.

To examine the outcome of pregnancy with fetal transverse cerebellar diameter (TCD) below the fifth percentile based on routine second- or third-trimester ultrasonography. We retrospectively analyzed the outcomes of 12344 women according to TCD Z scores based on systematic second- or third-trimester ultrasound examination between 2007 and 2015. Information on major malformations, chromosomal anomalies, intrauterine or neonatal demise, and other abnormal findings were collected. In total, 408 fetuses with small prenatal TCD underwent clinical investigation; 160 major malformations were noted, consisting mainly of neurological or cardiac anomalies (39,2%%). Chromosomal anomalies were reported in 39 (9.5%) and intrauterine or neonatal demise in 41 cases (10%). Major malformations and chromosomal anomalies were found in 46.4% and 10% of fetuses with extremely small TCD (Z score<-2.5), respectively, 31.3% and 12.7% of fetuses with small TCD (Z score between -2.0 and -1.645), and 39.6 % and 7.7% of fetuses with subnormal TCD (Z score between -2.0 and -1.645). Intrauterine or neonatal demise was noted in 22%, 8.8%, and 4.8% of fetuses with extremely small, small, and subnormal TCD, respectively (P<.05). Among intrauterine growth-restricted fetuses, fetal demise or neonatal adverse outcome was reported in 75%, 81.8%, and 18.5%, respectively. Of all the fetuses, 2.2% were lost to follow-up. A small cerebellar diameter below the fifth percentile is a relevant marker to detect associated anomalies during routine ultrasound examination in the second or third trimester. This is related to a high rate of fetal malformations, chromosomal anomalies, and genetic disorders, regardless of the severity of the cerebellar small size. Small TCD seems to be a prognostic factor for fetal growth restriction. Therefore, when facing a TCD below the fifth percentile, patients should be referred for further sonography and fetal karyotyping.

Comparative Study between Fetal Biometry and Transverse Cerebellar Diameter in Estimating Gestational Age in Third Trimester

Background: The exact determination of gestational age is so important in management of the antepartum care, and for adequate planning of proper intervention or therapy. Tanscerebellar diameter has great advantages in prediction of gestational age in cases of uncertain dates or in suspected intrauterine growth retardation. There are minimal data available about the relationship between tanscerebellar diameter and biparietal diameter in third trimester of pregnancy. Objective: The aim of the present study was to assess the accuracy of transcerebellar diameter (TCD) measurement in estimation of the gestational age during the third trimester compared to the current fetal biometric measurements including femur length and biparietal diameter. Patient and Method: The study included 500 pregnant women with sure and reliable dates fulfilling the inclusion criteria at the Department of Obstetrics and Gynecology, Al-Azhar (Bab Alsheria ) university Hospital, (inpatient and outpatient) from May 2018 till November 2018. The entire subjects were in the third trimester of pregnancy seen at 31 – 36 weeks, the transcerebellar diameter, the biparietal diameter and femur length were measured for determination of gestational age. Results: The results showed that the transcerebellar diameter (TCD) is more accurate than the biparietal diameter (BPD). There were insignificant statistical difference between transcerebellar diameter (TCD) and femur length (FL) for determination of gestational age in the third trimester whereas there was a significant difference between the transcerebellar diameter (TCD) and the biparietal diameter (BPD) for determination of gestational age in the third trimester. All those data were compared to the last menstrual period. Conclusion: Transcerebellar diameter is more reliable method of gestational age determination in third trimester of pregnancy than biparietal diameter. Transcerebellar diameter (TCD) and femur length (FL) can be used as a tool to assist in the assessment of gestational age in third trimester

Comparative Study between Fetal Biometry and Transverse Cerebellar Diameter in Estimating Gestational Age in Third Trimester

Background: The exact determination of gestational age is so important in management of the antepartum care, and for adequate planning of proper intervention or therapy. Tanscerebellar diameter has great advantages in prediction of gestational age in cases of uncertain dates or in suspected intrauterine growth retardation. There are minimal data available about the relationship between tanscerebellar diameter and biparietal diameter in third trimester of pregnancy. Objective: The aim of the present study was to assess the accuracy of transcerebellar diameter (TCD) measurement in estimation of the gestational age during the third trimester compared to the current fetal biometric measurements including femur length and biparietal diameter. Patient and Method: The study included 500 pregnant women with sure and reliable dates fulfilling the inclusion criteria at the Department of Obstetrics and Gynecology, Al-Azhar (Bab Alsheria ) university Hospital, (inpatient and outpatient) from May 2018 till November 2018. The entire subjects were in the third trimester of pregnancy seen at 31 – 36 weeks, the transcerebellar diameter, the biparietal diameter and femur length were measured for determination of gestational age. Results: The results showed that the transcerebellar diameter (TCD) is more accurate than the biparietal diameter (BPD). There were insignificant statistical difference between transcerebellar diameter (TCD) and femur length (FL) for determination of gestational age in the third trimester whereas there was a significant difference between the transcerebellar diameter (TCD) and the biparietal diameter (BPD) for determination of gestational age in the third trimester. All those data were compared to the last menstrual period. Conclusion: Transcerebellar diameter is more reliable method of gestational age determination in third trimester of pregnancy than biparietal diameter. Transcerebellar diameter (TCD) and femur length (FL) can be used as a tool to assist in the assessment of gestational age in third trimester

Role of Transcerebellar Diameter Measurement with Ultrasonography in Evaluation of Gestational age in Normal and Growth Restricted Fetuses

Background: To study the usefulness of transcerebellar diameter measurement ultrasonographically for the detection of gestational age in normal and intra uterine growth restricted fetuses and compare the gestation age determined by transcerebellar diameter with that determined by other parameters i.e. biparietal diameter, head circumference, abdominal circumference and femur length. Subjects and Methods: A prospective study with ultrasonographic evaluation of five hundred antenatal patients in gestational age of 14-39 weeks. The transcerebellar diameter was measured and the corresponding gestational age determined. The gestational age was also determined with other parameters such as biparietal diameter, head circumference, abdominal circumference and femur length. Transcerebellar circumference to abdominal circumference ratio was calculated. Results: There is statistically significant relationship between Transcerebellar diameter and gestational age in normal and intra uterine growth retarded pregnancies. Transcerebellar diameter showed good correlation with gestational age (correlation coefficient=0.979) in case of normal pregnancies and( correlation coefficient=0.942 )in cases of intra uterine growth retarded pregnancies Gestational age estimated by transverse cerebellar diameter measurements correlated well with gestational age estimated by biparietal diameter, head circumference, abdominal circumference and femur length. Transcerebellar circumference to abdominal circumference ratio remained fairly constant. Conclusion: Transcerebellar diameter can be used as a independent growth parameter to predict the gestational age in normal and in intrauterine growth retarded pregnancies cases. Transcerebellar diameter to abdominal circumference ratio is fairly constant throughout gestation and thus it is a useful gestational age independent parameter.

Comparison between taans cerebellar diameter, biparietal diameter and femur length for gestational age measurement accuracy in the 3rd trimester

Comparison between taans cerebellar diameter, biparietal diameter and femur length for gestational age measurement accuracy in the 3rd trimester

Ultrasonographic Evaluation of the Fetal Transverse Cerebellar Diameter (TCD) Measurement for Prediction of Gestational Age in 2nd and 3rd Trimesters of Pregnancy

Prediction of gestational age based on sonographic fetal parameters is perhaps the cornerstone in modern obstetrics. The transverse cerebellar diameter serves as a reliable predictor of GA in the fetus and is a standard against which abnormalities in other fetal parameters can be compared. A variety of sonographic fetal biometric parameters can be used to assess gestational age in the second and third trimesters of pregnancy. The TCD is an additional biometric parameter against which aberrations in other fetal parameters can be compared.&#x0D; Objective: To assess the predictability of GA calculated by fetal TCD measured in 2nd &amp; 3rd trimester of pregnancy on ultrasound.&#x0D; Methods: This was an cross-sectional study with a sample size 371 healthy, pregnant females with a normal fetus included aged 18 to 40 years, conducted in Gilani ultrasound center ferozpur road lahore. A standard 2nd and 3rd trimester ultrasound examination was done. In addition to the standard biometric parameters, the transcerebellar diameter was also measured. The collected data was subjected to statistical analysis.&#x0D; Results: Pearson product-moment correlation coefficient method was applied at a significance level of 1% (α = 0.01).using statistical software SPSS version 23.0. It was observed that BPD and TCD had a statistically significant, strong, linear correlation (r=0.976), GA of FL (r=0.978), LMP (r=0.976) P value (0.000) were considered significant.&#x0D; Conclusion: The TCD is a reliable parameter for the determination of GA in the 2nd &amp; 3rd trimesters of pregnancy.&#x0D; Int. J. Appl. Sci. Biotechnol. Vol 6(4): 379-385

Reliability of MR Imaging-Based Posterior Fossa and Brain Stem Measurements in Open Spinal Dysraphism in the Era of Fetal Surgery.

Fetal MR imaging is part of the comprehensive prenatal assessment of fetuses with open spinal dysraphism. We aimed to assess the reliability of brain stem and posterior fossa measurements; use the reliable measurements to characterize fetuses with open spinal dysraphism versus what can be observed in healthy age-matched controls; and document changes in those within 1 week after prenatal repair. Retrospective evaluation of 349 MR imaging examinations took place, including 274 in controls and 52 in fetuses with open spinal dysraphism, of whom 23 underwent prenatal repair and had additional early postoperative MR images. We evaluated measurements of the brain stem and the posterior fossa and the ventricular width in all populations for their reliability and differences between the groups. The transverse cerebellar diameter, cerebellar herniation level, clivus-supraocciput angle, transverse diameter of the posterior fossa, posterior fossa area, and ventricular width showed an acceptable intra- and interobserver reliability (intraclass correlation coefficient > 0.5). In fetuses with open spinal dysraphism, these measurements were significantly different from those of healthy fetuses (all with P < .0001). Furthermore, they also changed significantly (P value range = .01 to < .0001) within 1 week after the fetal operation with an evolution toward normal, most evident for the clivus-supraocciput angle (65.9 ± 12.5°; 76.6 ± 10.9; P < .0001) and cerebellar herniation level (-9.9 ± 4.2 mm; -0.7 ± 5.2; P < .0001). In fetuses with open spinal dysraphism, brain stem measurements varied substantially between observers. However, measurements characterizing the posterior fossa could be reliably assessed and were significantly different from normal. Following a fetal operation, these deviations from normal values changed significantly within 1 week.

A correlation of trans cerebellar diameter by ultrasonography and gestational age in second and third trimester

Background and Objectives: Increased perinatal mortality incidence has been seen amongst patients whose precise gestational age is unknown. Trans cerebellar diameter is a newer parameter in the estimation of gestational age. Therefore, the present study was conducted with the aim to determine the accuracy of trans cerebellar diameter in predicting gestational age during second and third trimester of pregnancy.&#x0D; Materials and Methods: The present study was conducted in the Mithila Hospital,Janakpurdham for a period of 1 year. The study included a total of 160 females with singleton pregnancies during their 2nd or 3rd trimester. The characteristic butterfly appearance of the cerebellum hinted the location of posterior fossa. All the data was arranged in a tabulated form and analyzed statistically. Data was expressed in the form of mean with standard deviation. SPSS software16 was used for the analysis of the data.&#x0D; Results: The present study enrolled 160 subjects, out of which 80 were in their second trimester and 80 were in their third trimester. The mean transcerebellar diameter of subjects in second trimester was 20.22±4.87 and it was 36.01±2.89 amongst subjects in their third trimester. As the gestational age advances, the transcerebellar diameter also increases with it in a linear manner.&#x0D; Conclusion: Transcerebellar diameter can be used as a reliable parameter to estimate the gestational age and is also not altered in cases of intrautering growth restriction.

FETAL TRANSVERSE CEREBELLAR DIAMETER MEASUREMENT;

Objective: To determine the accuracy of fetal transverse cerebellar diametermeasurement in the prediction of gestational age in growth restricted fetuses. Material andmethods: This controlled was conducted at Sobhraj Maternity Hospital, Karachi from July 2012to June 2013. A total of 100 pregnant women in the third trimester of pregnancy satisfying theeligibility criteria were included. Among these 50 were fetuses with normal fetal growth and50 growth restricted fetuses. Results: The mean transverse cerebellar diameter in the fetusesshowing normal growth was not statistically different from the mean transverse cerebellardiameter in the growth restricted fetuses (p-value = 0.219). Conclusions: Transverse cerebellardiameter measurement can be used reliably for accurate estimation of gestational age in growthrestricted fetuses.

Fetal brain morphometry on prenatal magnetic resonance imaging in congenital diaphragmatic hernia

Many infants with congenital diaphragmatic hernia (CDH) show brain abnormality on postnatal brain MRI related to severity of CDH, degree of lung hypoplasia, intrathoracic liver, right diaphragmatic hernia and large diaphragmatic defect. It is not known whether these factors affect brain growth in utero in CDH. To assess prenatal brain morphometry and abnormalities on fetal MR in congenital diaphragmatic hernia. We retrospectively reviewed 109 fetal MRIs in 63 fetuses with CDH from 2009 to 2014 (27 died before discharge, 36 survived to discharge). We compared brain injury and gestational-age-corrected z-scores of brain measurements between survivors and non-survivors. We assessed correlations between brain abnormalities and CDH severity. Enlarged extraaxial space was the most common abnormality, frequently seen on fetal MRI at >28weeks of gestation, similar in survivors versus non-survivors. Anteroposterior cerebellar vermis dimension at >28weeks of gestation was smaller in non-survivors compared to survivors (P=.02) and positively correlated with observed/expected total fetal lung volume (P=.01). Transverse cerebellar diameter at >28weeks of gestation was also positively correlated with observed/expected total fetal lung volume (P=.04). We did not identify maturational delay, abnormal parenchymal signal or intracranial hemorrhage on fetal MRI. Enlarged extraaxial spaces in the third trimester was the most common abnormality on fetal MRI in congenital diaphragmatic hernia. Cerebellar dimensions on fetal MRI are associated with CDH severity. There was no major brain parenchymal injury on fetal MRI, even in the third trimester, in CDH survivors and non-survivors.

Comparison between Taans Cerebellar Diameter, Biparietal Diameter and Femur Length for Gestational Age Measurement Accuracy in The 3rd Trimester

Background: the provision of obstetric and neonatal care, as well as the public health monitoring of pregnancy outcomes, relies upon the accurate determination of gestational age. Uncertain gestational age has been associated with adverse pregnancy outcomes including low birth weight, preterm delivery and perinatal mortality and independent of maternal characteristics. Many patients in Egypt due to socio-economic reasons come for their first antenatal visit in the third trimester. Most of them are uneducated and come from remote areas. Also, many being lactating mothers are unsure of their LMP or have irregular cycles. Because of non-availability of any dating scans or earlier ultrasound and uncertainty in LMP, it becomes very difficult to calculate their due dates, so many pregnancies considered to be preterm or posterm were wrongly classified. The use of ultrasonography has significantly improved evaluation of fetal growth and development and had permitted prenatal diagnosis of a variety of congenital malformations. Ultrasonographic fetal biometry is highly reliable in the first and second trimester of pregnancy, but reliability of any ultrasound method greatly diminishes as gestational age advances, in the third trimester, reliability of any single ultrasound parameter alone is poor without correlation with other parameters. Objective: in our study, TCD was compared to FL and BPD in accuracy of assessment of gestational age in the third trimester of pregnancy. We correlated between the three parameters, Transcerebellar (TCD) and Biparietal diameter (BPD) and Femur length (FL), for accurate determination of gestational age in third trimester of pregnancy. Methods: a total of 200 pregnant women in the third trimester pregnancy were assessed in this observational study in Department of Obstetrics and Gynecology, Damietta Hospital, Al-Azhar University (Outpatient) by two-dimensional ultrasound to assess the accurate method for assessment of gestational age in the third trimester of pregnancy. Examinations were performed after a verbal consent from the patient with the patient lying in the dorsal supine position. Two dimensional ultrasounds were carried out. Fetal biometry and amniotic fluid volume were assessed. All women included in this study were subjected to history taking and clinical examination. Results: we found that out of 200 patients, TCD gave correct assessment of gestational age within 3 days in 118 patients (59%) and within 1 week in 180 patients (90%). While, FL gave correct assessment of gestational age within 3 days in 92 patients (46%) and within 1 week in 160 patients (80%). The least accurate was BPD that gave correct assessment of gestational age within 3 days in 59 patients (29.5%) and within 1 week in 120 patients (60%). Conclusion: from this study, we concluded that TCD was the most accurate method for assessment of gestational age in the third trimester followed by FL and the least accurate was the BPD. Also, by combining accuracy of TCD (90%) and that of FL (80%) we can be near certain of gestational age in most of our patients even if they are unsure of their dates. Recommendations: measuring TCD as routine in the third trimester as it has the same accuracy as the current fetal biometry (BPD and FL).

Comparison between taans cerebellar diameter, biparietal diameter and femur length for gestational age measurement accuracy in the 3rd trimester

Background: the provision of obstetric and neonatal care, as well as the public health monitoring of pregnancy outcomes, relies upon the accurate determination of gestational age. Uncertain gestational age has been associated with adverse pregnancy outcomes including low birth weight, preterm delivery and perinatal mortality and independent of maternal characteristics. Many patients in Egypt due to socio-economic reasons come for their first antenatal visit in the third trimester. Most of them are uneducated and come from remote areas. Also, many being lactating mothers are unsure of their LMP or have irregular cycles. Because of non-availability of any dating scans or earlier ultrasound and uncertainty in LMP, it becomes very difficult to calculate their due dates, so many pregnancies considered to be preterm or posterm were wrongly classified. The use of ultrasonography has significantly improved evaluation of fetal growth and development and had permitted prenatal diagnosis of a variety of congenital malformations. Ultrasonographic fetal biometry is highly reliable in the first and second trimester of pregnancy, but reliability of any ultrasound method greatly diminishes as gestational age advances, in the third trimester, reliability of any single ultrasound parameter alone is poor without correlation with other parameters. Objective: in our study, TCD was compared to FL and BPD in accuracy of assessment of gestational age in the third trimester of pregnancy. We correlated between the three parameters, Transcerebellar (TCD) and Biparietal diameter (BPD) and Femur length (FL), for accurate determination of gestational age in third trimester of pregnancy. Methods: a total of 200 pregnant women in the third trimester pregnancy were assessed in this observational study in Department of Obstetrics and Gynecology, Damietta Hospital, Al-Azhar University (Outpatient) by two-dimensional ultrasound to assess the accurate method for assessment of gestational age in the third trimester of pregnancy. Examinations were performed after a verbal consent from the patient with the patient lying in the dorsal supine position. Two dimensional ultrasounds were carried out. Fetal biometry and amniotic fluid volume were assessed. All women included in this study were subjected to history taking and clinical examination. Results: we found that out of 200 patients, TCD gave correct assessment of gestational age within 3 days in 118 patients (59%) and within 1 week in 180 patients (90%). While, FL gave correct assessment of gestational age within 3 days in 92 patients (46%) and within 1 week in 160 patients (80%). The least accurate was BPD that gave correct assessment of gestational age within 3 days in 59 patients (29.5%) and within 1 week in 120 patients (60%). Conclusion: from this study, we concluded that TCD was the most accurate method for assessment of gestational age in the third trimester followed by FL and the least accurate was the BPD. Also, by combining accuracy of TCD (90%) and that of FL (80%) we can be near certain of gestational age in most of our patients even if they are unsure of their dates. Recommendations: measuring TCD as routine in the third trimester as it has the same accuracy as the current fetal biometry (BPD and FL).