In order to strengthen the argument that for both races to survive (and Ron has been heading towards a reconciliation for a long time) they must intermingle to procreate, perhaps Caprica has to miscarry with Ellen revealing that, genetically, the eight cannot have children together nor can the five with any of the eight. And Hera would remain special because she's proof that the ONLY way the Cylons can survive in some form is by having children with humans. It would be tragic if Caprica were to lose the baby, but it would also be realistic (and human) if she miscarried.

Of course, Evil Nurse Ishay may have her own agenda. :/