About 1 in every 3 to 5 known pregnancies ends in miscarriage. This can happen a variety of different ways. Some women will have some of the signs of miscarriage below, while others have no problems whatsoever and find out at a later prenatal appointment that their baby has died (missed miscarriage). Here is more on the signs that may indicate a problem with your pregnancy from About.com Guide to Miscarriage and Pregnancy Loss.
If you are having blood work done, your practitioner is looking at your hCG levels. While there are ranges to look at which can give you some basic information about a pregnancy. Repeated numbers give a better look at what is going on inside. When the hCG levels begin to fall, you may be having a miscarriage or other pregnancy complication, including an ectopic pregnancy.
Cramping can be another symptom of early pregnancy that leaves you feeling worried. When you do not experience bleeding with the cramping, the chances are good that it is simply normal cramping from the uterus stretching and growing. Though sometimes cramping can precede bleeding.
cyst or other condition that is not associated with your pregnancy, you will need to be evaluated.