Unlike blood from the lining, however, blood from implants outside the uterus has no way to leave the body. Instead, it is absorbed by surrounding tissue, which can be painful. As the cycle recurs month after month, the implants may get bigger. Sometimes, a collection of blood called a sac or cyst forms. If a cyst ruptures, it often causes excruciating pain.
Symptoms vary from patient to patient.
Severity of symptoms frequently has little to do with the extent of the implants. For instance, some women with just a few implants have severe pain, while some with many implants have little or no pain. For some, pain starts before or during menstruation and gets worse as the period progresses. Others report pain at a variety of times during the month. There may be a sharp pain at ovulation when the egg, trying to move into the fallopian tube, causes a cyst on the ovary to burst.