'Bachelor' Star Gia Allemand -- Medical Mystery ... Family Emotional Outside Hospital

With "Bachelor" star Gia Allemand still in critical condition ... the reality star's mother and sister shared an emotional embrace outside the Louisiana hospital where Gia's being treated.

Allemand has been hospitalized since Monday, when she was admitted after suffering what her reps are calling a "serious emergency medical event."

So far, the details surrounding the medical emergency are unclear ... but we do know she was alone when the initial incident occurred and she was taken to the hospital by her mother.

TMZ spoke with her mother yesterday -- who wouldn't reveal much ... only telling us, "Gia is very sick." She also asked for her fans to pray for Gia's health.