What Causes Dark Blood Discharge From Vagina During Pregnancy?

Hi, doctor, I am 46 years old. now I am pregnant. I see black color blood discharging from my vagina. but just little every day. My last period was may 7. I went emergency room. they check pelvic test and ultra sound too. but, doctor said he couldn t find any because it is too early. he told me to ob.gyn. I am waiting till I get my medicaid. can i get healthy baby? or do I have to face any serious miscarige?