What are the chance of this beign a miscarriage?

this is about my mom not me. yesterday we were out of town..she said she hasnt had a period for 5 to 6 months. which is normal for her. but anyway she went pee and she said a thing came out of her and plopped into the toilet. it was kinda redish and white..but her gyn told her it was probably a blood clot since she hasnt had a period in so long and she told my mom to take a pregnacy test. so she did and it came up positive. so she went to the hospital and got tests and stuff and the doctor said he thinks it is early signs of her being pregnant. im am so nervous :_(