Spotting from the vagina implies blood loss from somewhere. I’m assuming for that sake of this discussion that we are not talking about bleeding during pregnancy or during menstruation.
Spotting is relatively uncommon and occurs in about 5 percent of women. Spotting most often comes from the lining of the uterus. For women on some form of oral contraceptive or injectable or subdermal hormone contraception, bleeding can occur as a result of hormone manipulation. This bleeding is a nuisance, but it is benign.
There are other possible causes of spotting. Fibroids are benign, smooth muscle tumors in the uterus. They can cause a lot of bleeding. However, fibroids can also be malignant, and some forms of cancer can be very aggressive. Bleeding might also occur as a result of bacterial infection such as gonorrhea, chlamydia, mycoplasma, ureaplasma, group B strep, and bacterial vaginosis.
Spotting from the vagina can be a sign of vaginitis or carcinoma of the vagina. Bleeding can also come from the vulva. This form of spotting is most often a result of cancer. Some sources of the spotting might also come from the rectum or hemorrhoids.
Spotting or bleeding from the rectum, vulva, vagina, cervix, or uterus should be taken seriously. You should visit your physician at the first opportunity. But the most common cause of gynecological cancer is cancer of the uterine lining (endometrial cancer).
Uterine cancer has a five-year survival rate of about 95 percent. This good survival rate depends largely upon early warning signs, especially after menopause. Although some premenopausal women have cancer of the uterine lining, most women who develop this cancer are postmenopausal.
For premenopausal women, spotting or bleeding associated with cancer of the lining of the uterus is commonly associated with heavy menstrual periods or bleeding between periods.
Not all cancers show up as spotting. Tubal cancer is very rare and rarely shows up as spotting. This kind of cancer appears most often with a clear vaginal discharge which can be an accurate warning sign of a serious cancer.
Spotting, whether premenopausal or postmenopausal, can be a sign of a serious condition. With any spotting, I recommend you seek medical attention as soon as possible.