I am about 6 weeks pregnant. About two weeks ago I started spotting and I went to the doctor. He drew blood and did an ultrasound. My HCG level had doubled in just 2 days and he followed up with an ultrasound a few days later. You could see the baby and the heartbeat but I was having a brown discharge. Before I left the doctor told me that I would see that but he didn't say for how long. I understand that the brown discharge is supposed to be leftover blood. When he did the ultrasound he said my uterus is heart-shaped and inverted and on one side he saw the baby and on the other there was a sack with blood in it. He didn't think it was a twin pregnancy though. Is it possible that it was and that I miscarried on of the babies? Does anyone know how long this discharge will last?

It's possible this was due to a twin pregnancy, but it is not uncommon for there to be some bleeding/spotting take place as the placenta forms. This blood can pool up and later be discharged, either as spotting, bleeding, or brownish discharge. In most cases, as long as it is not fresh blood, either with or without cramping, it is not a concern.