Rare Pregnancy Symptoms: Period-Like Bleeding with Negative Test

It is unlikely but very rare:

You might experience what appears to be a period while you're pregnant. But that discharge of tissue and tissue from the pregnancy sac would be a miscarriage — not menstrual activity in the body as you normally know it.

However; the pregnancy may continue after menstruation-looking bleeding in very very rare occasions where this could be a sign of: