Assessment of gestational age; comparison between transcerebellar diameter versus femur length on ultrasound in third trimester of pregnancy

ABSTRACT

To compare correct assessment of gestational age between Transcerebeller diameter versus femur length in third trimester [28-40] using first day of last menstrual period for actual period of gestation. Cross-sectional descriptive study. Department of Obstetrics and Gynecology, Bahawal Victoria Hospital, Bahawalpur from Jun 2012 to Dec 2012. This study was performed on 327 patients in third trimester of pregnancy from 28-40 weeks fulfilling the inclusion criteria. Ultrasound measurements of transcerebellar diameter [TCD] and femur [FL] were made with commercially available real time ultrasound equipment Toshiba Nemio-10 model 2009, Transducer frequency 50/60 Hz. Collected data was analyzed by SPSS version 10. Out of 327 patients, TCD was found to give correct assessment corresponding to the gestational age by LMP in 262 [80.1%] patients, while in 232 [70.9%] patients FL was found to give correct assessment corresponding to the gestational age by LMP. Transcerebellar diameter is more reliable method of gestational age determination in third trimester of pregnancy than femur length. TCD can be used as a tool to assist in the assessment of gestational age in third trimester