Brown spotting or bleeding is common for pregnant women. Brown spotting could be a sign of miscarriage or may even result from a condition that is unrelated to the pregnancy. It is advisable to seek medical attention for any brown spotting that doesn't fit the criteria of implantation bleeding. Brown spotting during pregnancy that is associated with symptoms such as abdominal pain and cramping requires emergency medical attention. Considering brown spotting a result of 'old' bleeding is wrong and even fresh bleeding might also result in brown spotting if it is first seen a few hours after bleeding.

Any brown spotting that is not implantation bleeding warrants evaluation. Presence of other symptoms including cramping, abdominal pain, dizziness, fainting, and fever require emergency medical attention as they indicate a serious underlying condition. Management of the brown spotting depends on its cause and the duration of the pregnancy. The most common causes of brown spotting during pregnancy are listed in the table below.

Implantation Bleeding

Implantation bleeding may present with varying amounts of bleeding. Sometimes it might be severe enough to mimic a period, while at other times it may just appear as brown spotting. Implantation bleeding occurs approximately two weeks after conception, and roughly corresponds to the time of the missed period. Implantation bleeding is a normal phenomenon and is not a cause for concern. No treatment is needed for implantation bleeding during pregnancy.

Sexual Intercourse

One of the most significant causes of brown spotting during pregnancy is sexual intercourse. Due to various physiological changes during pregnancy, the cervix becomes more prone to injury and bleeding. The cervix might be injured during sexual intercourse, which may cause brown spotting on the undergarments.

Miscarriage

Both threatened and spontaneous abortion may result in brown spotting. Often these are associated with other symptoms, but brown spotting might be the first and only one. Presence of other symptoms such as cramping pains and passing of 'tissue' or clots through the vagina suggest a miscarriage. The miscarriage (or spontaneous abortion) might be complete or incomplete. Incomplete abortions are usually treated with uterine evacuation (Dilation and Curettage or D&C). Intrauterine death of the fetus without passage of tissues (i.e. fetus still lying in the uterine cavity) is called missed abortion. Missed abortions are also treated with D&C.

Ectopic Pregnancy

Ectopic pregnancy is a rare cause of brown spotting. However, it is considered a very important cause due to the gravity of the condition. In an ectopic pregnancy, the embryo implants and develops in the fallopian tube instead of the uterus. Other associated symptoms include pain and cramping in the abdomen. If severe internal bleeding occurs, then dizziness or even fainting may also occur. Ectopic pregnancy is a potentially life-threatening condition that needs to be terminated when diagnosed.

Placental Abnormalities

Brown spotting can also occur in placental abnormalities such as placenta previa and placenta abruption. However, frank vaginal bleeding is the more likely presentation. Placenta abruption is usually associated with pain, whereas placenta previa is not. Placenta previa refers to a condition in which the placenta covers the cervical opening. Vaginal bleeding is the more common presentation of placenta previa, but brown spotting can also occur. In the condition known as placenta abruption, the placenta separates from the uterus. Vagina bleeding is also the more likely presentation for this condition, but occasionally brown spotting might occur. This is a serious condition requiring urgent medical attention.

Molar Pregnancy

Gestational Trophoblastic Diseases or Molar pregnancies are pregnancy tumors that are characterized by the presence of abnormal tissue in the uterus. These conditions may masquerade as pregnancies and sometimes even the fetal tissue (although abnormal) might be present. Some of the gestational trophoblastic diseases are malignant cancers and may spread quickly to other parts of the body. Gestational trophoblastic diseases may present with a variety of symptoms including brown spotting. Treatment depends on the particular type of molar pregnancy that is present.

Labor

The start of labor is also associated with slight vaginal bleeding, which might appear as brown spotting or frank blood. This occurs due to the passage of the mucus plug of the cervix. If the woman has not reached her 37th week yet, this onset of labor is referred to as pre-term labor. This passage of the mucus plug and vaginal bleeding/brown spotting may occur many days or even weeks before the onset of other symptoms of labor (backache, cramps, uterine contractions, etc.)

Other Conditions Not Related to Pregnancy

Beyond the aforementioned causes that are mainly related to the pregnancy, any other gynecological cause of brown spotting might be present in addition to the pregnancy. Common causes of brown spotting including cervicitis and vaginitis (caused by sexually transmitted diseases and other infections), injury or trauma to vagina or cervix, cervical ectropion (cervical erosions), cancers of cervix/vagina/uterus, and cervical polyps might also result in brown spotting. Non-gynecological conditions like urethral polyp or kidney conditions might also result in brown spotting in the undergarments.

Often no cause of this brown spotting is discerned, though the pregnant woman and her fetus are determined healthy upon careful medical evaluation. Such unexplained brown spotting during pregnancy is very common.