How Can A USG Taken At 11 Weeks Of Pregnancy Be Confirmed To Be Normal?

In my 11 weeks of the ultrasound shows uterus shows normal enlargement and single live intrauterine fetus in variable presentation cardiac activities and move meets r noted crl 4.41 cm corresponding to 11 weeks and one day Fhr measures 156bpm Placenta is left anterior with grade 0 maturity Lower end of placenta is 14mm away from close os The rim of sub amnionic separation is seen Liquor appears normal and afi measures 14 cm by four quadrant method the fetal spine shows normal three lines with no disruption there is no hydrocephalus