ultrasound shows there is a single intrauterine pregnancy in cephalic presentation with good fetal movement and cardiac activity.biparietal diameter:7.5cm.=28 5/7 weeks AOG,femoral length:5.2cm.=28 2/7weeks AOG,placenta:posterior,grade 0,amniotic fluid:adequate,averarage ultrasound age:28 4/7 weeks AOG,needs further interpretation