Talk to Gynecologist on Baby HeartBeat On And Off

my wife got ultra sound in 9th week. they said that the growth stopped at 8th week. heart beat came and went but sac was healthy. doctor gave progesterone for 5 days which means at 9 week when we went for check up you have to put this progeffik in vagina for 5 days after seeing the ultrasound. does it mean that fetus heartbeat can occur back or can restart ? has any one heard the case of heartbeat coming after 10 week. doctor thinks that the sac is still very healthy and may not need of D&C.