Most fetal abnormalities are detected early in the first and second trimesters. As a result, the detection of abnormalities at 35-37 weeks is quite rare. By this stage, the fetus is nearly mature, and ultrasound assessments will focus on anatomy and biometrics. This allows doctors to evaluate the fetus's development before birth and identify any abnormalities that may have gone undetected in earlier ultrasounds. Such assessments can improve outcomes by facilitating thorough preparations for delivery and early neonatal intervention.