A low hCG level can mean different things depending on how far along you are. If you are very early in your pregnancy, then hCG levels will likely be very low but in a normal, healthy pregnancy they will naturally increase rapidly.
However, if your hCG level starts to decrease, there may be a risk you are having/have had a miscarriage11.
If your hCG level is consistently low, with no increase or decrease, or if you experience any pain or bleeding, see your doctor immediately to rule out the risk of an ectopic pregnancy, when the fertilized egg implants outside the uterus11.