I've had two pregnancies that ended in which both babies heart just stopped beating one at 23 weeks one at 27 weeks. I'm 10wks pregnant now will this repeat?

Not necessarily. You most probably would have an another preterm baby, because the probability with having two prior preterm deliveries is getting higher. But it is not necessarily that the cause of preterm delivery would be the heart issues, unless you have a family history of it, or prior babies had the inherited heart diseases. You have to have a close follow up with your obstetrician anyway for that reason.