Gynaecology & Obstetrics Which among the following is the BEST parameter for estimation of fetal age by ultrasound in third trimester? A Femur length B Biparietal diameter C Abdominal circumference D Inter-ocular distance 💡 Explanation Which among the following is the BEST parameter for estimation of fetal age by ultrasound in third trimester? ✓ Correct Answer: A. Femur length