If the gestational sac—which encloses the developing baby and contains amniotic fluid—isn't visible by around five weeks gestation ... pregnancy isn't viable, a miscarriage has already ...

CRL: Crown—rump length; EV: Embryo volume; FV: Fetal volume; GSV: Gestational sac volume ... had a sensitivity of 38.5% (placental quotient at 12 weeks) versus 44.8% (uterine artery Doppler ...