Why doesn't Ingrid get over Henry and always desperately hoped to marry him? It is revealed that Alba time-traveled to them when they still were a couple. While Henry in his twenties is totally oblivious who that weird, bare-footed kid who follows him around is, Ingrid is implied to figure it out. She must assume Alba is her and Henry's daughter in the future.
All the miscarriages that Clare endures are heartbreaking and horrifying enough, now think about what would happen if Alba ever gets pregnant. She not only might have the same issue of the fetuses time travelling away from her, but quite possibly of she herself time travelling away from her fetuses meaning one moment you could be looking at Alba then suddenly just a bundle of clothing and... something else.
The fetus being left seem highly unlikely unless the child was being rejected and would therefore miscarry anyway. But if it does work on fetuses, what about other things in the body, like cancerous tumors?
And think about the people who have artificial items in them that they need like a pacemaker...