Gynaecology & Obstetrics Best parameter measured by ultrasound to assess foetal maturity in the first trimester? A Crown - rump length B Biparietal diameter C Ratio of transverse diameter of abdomen to foetal head diameter D Transverse diameter of abdomen 💡 Explanation Best parameter measured by ultrasound to assess foetal maturity in the first trimester? ✓ Correct Answer: A. Crown - rump length