Hello, I think I can help you. The most obvious and most common reason why the HCG levels are low is because the age of the pregnancy was not calculated correctly. They calculate the correct level of HCG based on the first date of the last menstrual period. If the level is lower than this then they start to be concerned. However, sometimes some women ovulate later than others or have different cycles, or conceived at a different time. This is especially common in women of her age. Actually, the HCG level should double every 48 hours. If it does not, than she may be having a miscarriage. If she is not having any symptoms of a miscarriage (i.e. cramping, bleeding, ect) than this is less likely. Another way to evaluate the pregnancy would be to do a transvaginal ultrasound. This way, they can tell if a viable pregnancy is inside the uterus. However, she must be pregnant for greater than 5 weeks to perform this test. I hope she doesn t worry too much about this. The actual level of HCG is not so important, sometimes it varies. The trend of HCG is more important. You have to ensure that it is increasing in the early weeks of pregnancy. I will keep my fingers crossed for her.