Vaginal bleeding refers to bleeding through the vagina, including bleeding from the vaginal wall itself as well as (and more commonly) bleeding from another location of the female reproductive system. Generally, it is either a physiologic response during the non-conceptional menstrual cycle or caused by hormonal or organic problems of the reproductive system. Vaginal bleeding may occur at any age, but always needs investigation when encountered in female children or postmenopausal women. Vaginal bleeding during pregnancy may indicate a possible pregnancy complication that needs to be medically addressed.
Blood loss per vaginam (Latin: through the vagina) (PV) typically arises from the lining of the uterus (endometrium), but may arise from uterine or cervical lesions, the vagina, and rarely from the Fallopian tube. During pregnancy it is usually but not always related to the pregnancy itself. Rarely, the blood may actually arise from the urinary tract (hematuria), although the vast majority of women can identify the difference. It can also be a sign of vaginal cancer.
Differential diagnosis 
Bleeding in children 
Bleeding before the expected time of menarche could be a sign of precocious puberty. Other possible causes include the presence of a foreign body in the vagina, molestation, vaginal infection (vaginitis), and rarely, a tumor.
Premenopausal women 
- Menstruation. Exceptionally heavy bleeding during periods is termed menorrhagia or hypermenorrhea, while light bleeding is called hypomenorrhea.
- Breakthrough bleeding in women on combined oral contraceptives
- Withdrawal bleeding which can occur upon discontinuation of hormonal stimulation. Withdrawal bleeding is generally regarded as a normal physiological response.
- If bleeding occurs between periods, this is not necessarily pathological, but it is termed intermenstrual bleeding. If no period can be identified due to the unpredictable bleeding, metrorrhagia is used.
- Dysfunctional uterine bleeding is a common cause of menorrhagia and irregular bleeding. It is due to a hormonal imbalance, and symptoms can be managed by use of hormonal contraception (although hormonal contraception does not treat the underlying cause of the imbalance). If it is due to polycystic ovary syndrome, weight loss may help, and infertility may respond to clomifene citrate.
- Uterine fibroids (leiomyoma) are benign tumors of the uterus.
- Cervical cancer may occur at premenopausal age, and often presents with "contact bleeding" (e.g. after sexual intercourse)
- Uterine cancer will lead to irregular and often prolonged bleeding.
- In recently pregnant women who have been delivered of a baby or who have had a miscarriage, vaginal bleeding may be a sign of endometritis or retained products of conception.
Pregnant women 
Vaginal bleeding occurs during 15-25% of first trimester pregnancies. Of these, half go on to miscarry and half bring the fetus to term. There are a number of causes including rupture of a small vein on the outer rim of the placenta. It can also herald a miscarriage or ectopic pregnancy, which is why urgent ultrasound is required to separate the two causes. Bleeding in early pregnancy may be a sign of a threatened or incomplete miscarriage.
In the second or third trimester a placenta previa (a placenta partially or completely overlying the cervix) may bleed quite severely. Placental abruption is often associated with uterine bleeding as well as uterine pain.
Postmenopausal women 
- 30% unopposed estrogen
- 30% atrophic endometritis / vaginitis
- 15% endometrial cancer
- 10% endometrial polyps or cervical polyps
- 5% endometrial hyperplasia
- 10% other
Diagnostic approach 
The diagnosis can often be made on the basis of the bleeding history, physical examination, and other medical tests as appropriate. Typically a pregnancy test and additional hormonal tests, a Pap smear, a transvaginal ultrasound are needed. If bleeding was excessive or prolonged, a CBC may be useful to check for anemia. Abnormal endometrium may have to be investigated by a hysteroscopy with a biopsy or a dilation and curettage.
The treatment will be directed at the cause. Hormonal bleeding problems during the reproductive years, if bothersome to the woman, are frequently managed by use of combined oral contraceptive pills.
Severe acute bleeding, such as caused by ectopic pregnancy and post-partum hemorrhage, leads to hypovolemia (the depletion of blood from the circulation), progressing to shock. This is a medical emergency and requires hospital attendance and intravenous fluids, usually followed by blood transfusion. Once the circulating volume has been restored, investigations are performed to identify the source of bleeding and address it. Uncontrolled life-threatening bleeding may require Uterine artery embolization (occlusion of the blood vessels supplying the uterus), laparotomy (surgical opening of the abdomen), occasionally leading to hysterectomy (removal of the uterus) as a last resort.
A possible complication from protracted vaginal blood loss is iron deficiency anemia, which can develop insidiously. Eliminating the cause will resolve the anemia, although some women require iron supplements or blood transfusions to improve the anemia.
- Farlex Medical Dictionary > Withdrawal Bleeding, in turn citing Mosby's Medical Dictionary, 8th edition
- Snell, BJ (2009 Nov-Dec). "Assessment and management of bleeding in the first trimester of pregnancy.". Journal of midwifery & women's health 54 (6): 483–91. doi:10.1016/j.jmwh.2009.08.007. PMID 19879521.