16mm pregnancy sac, no embryo bud fetal heart, how to do

Pregnant women, check the gestational sac has 16mm, but did not see the fetal heart fetal teeth, if the pregnancy time is less than 42 days, should be caused by the gestational sac development time is short, you can wait a week to go to the hospital to do color ultrasound examination. If there is no fetal heart fetal teeth, this may be a hollow sac, need to do abortion surgery.