Study observation.general transvaginal 1st trimester:Imp:Pt:^Fetus:Nar:US
study observation.general transvaginal 1st trimester:imp:pt:^fetus:nar:us
Study observation.general transvaginal 1st trimester:Imp:Pt:^Fetus:Nar:US
study observation.general transvaginal 1st trimester:imp:pt:^fetus:nar:us