miscarriages

Chaylee
A friend of mine was due in November and is now in the hospital I'm assuming a misscarry from her post because she is having surgery. I've had a couple and never had to go to the doctor. We are sure it's not in her tubes because there was already an ultrasound. What week do you have to be to need assistance. Or could anyone give me insight on why she might need doctors attention at the stage she is at.