Introduction: Appropriate assessment of gestational age is of paramount importance in obstetric care. Uncertain gestational age has been associated with adverse pregnancy outcome including low birth weight, spontaneous preterm delivery and perinatal mortality. Objectives: To evaluate the usefulness of fetal femur length in Assessment of Gestational Age in Third Trimester. Materials and Method: In the present study total 100 pregnant female attending antenatal clinic of the study institute in third trimester were enrolled. Detailed demographic profile including age, address etc was obtained. Detailed history regarding the exact knowledge of her LMP, cycle regularity and duration of cycle was taken. All patients then underwent detailed examination i.e. general and systematic examination. The gestational age at time of scanning was confirmed by LMP, and abdominal examination. All the women in the study underwent ultrasonoghraphy. The ultrasound was done by a single operator to avoid bias in observations. All the fetal parameters were assessed and special attention was given to the femur length. The collected data was entered in Microsoft excel. Primary analysis was conducted by using Epi Info statistical software. Results: The mean age of the women was 25.43±4.72 years. The gestational age according to the LMP was calculated and it was observed that majority of the patients were of 35 weeks gestation (14%) followed by 30 weeks (12%). The mean gestational age was 33.53±3.368 weeks. The gestational age was also calculated by using Femur length on ultrasonoghraphy and it was seen that majority of the women were of 38 weeks of gestational age (16%) followed by 32 weeks of gestation with mean gestational age of 34.15±3.40 weeks. The gestational age calculated by LMP and FL showed no statistically significant difference. Thus the gestational age calculated from femur length was comparable with the gestational age calculated by LMP. The correlation coefficient between GA by LMP and GA by FL was 0.9603with P-Value <0.05 thus there was significant correlation between GA by LMP and FL. Conclusion: The gestational age estimated from femur length was correlated with the gestational age calculated from the LMP with Correlation coefficient of 0.9603 with P-Value <0.05. Thus we conclude that the foetal femur length can be useful in evaluation of Assessment of Gestational Age in Third Trimester and the findings.

Keywords: Fetal Femur Length; Gestational Age; Ultrasonographic Age Estimation.