Gestational age and ultrasonic measurement of gestational sac, crown-rump length and biparietal diameter during first 15 weeks of pregnancy.
D002508:Cephalometry; D005260:Female; D005333:Fetus / Q000033:anatomy & histology* / Q000502:physiology; D005865:Gestational Age; D006128:Growth; D006801:Humans; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D014463:Ultrasonography