What Is Early Pregnancy Bleeding?

Early pregnancy bleeding refers to vaginal bleeding during the first trimester, or the first three months of pregnancy. It usually occurs after fertilization when the fertilized egg implants in the lining of your uterus. This type of bleeding is also sometimes called implantation bleeding.

While bleeding during pregnancy may seem like a problem, it's actually very common early on. About 15% to 25% of pregnant women have bleeding in the first trimester, the first three months of pregnancy. The bleeding is typically light. Even so, it's best to talk to your obstetrician-gynecologist if you experience any kind of bleeding during your pregnancy.

Sometimes early pregnancy bleeding can signal a number of problems, including miscarriage and ectopic pregnancy. Bleeding with pain or bleeding that is heavier than a normal menstrual amount is a reason for further investigation.

Causes of Early Pregnancy Bleeding

Implantation is the most common cause of early pregnancy bleeding, but it can also occur due to several other normal causes:

• The cervix may bleed more easily during pregnancy because more blood vessels are developing in this area. 
• You may have spotting or light bleeding after sexual intercourse or after a Pap test or pelvic exam, which involve contact with the cervix.

The bleeding in these cases should be light and last only a few days. If bleeding is heavier or lasts longer than a few days or occurs with pain, there could be a problem with the pregnancy, such as a miscarriage, which refers to pregnancy loss in the first 20 weeks of pregnancy. It is also called early pregnancy loss. Bleeding and cramping are signs of a miscarriage. However, about one-half of women who have a miscarriage do not have any bleeding beforehand.

Diagnosis

Your healthcare provider will review your overall health and details of your pregnancy. A pelvic examination can help identify nonpregnancy-related conditions like vaginal infections or polyps.

If you have a miscarriage, your practitioner will advise you on next steps to make sure your body expels any remaining tissue. If pregnancy loss has not occurred, they may order blood work, lab tests, or ultrasound imaging.

To narrow the cause or impact of your bleeding, your medical professional may order blood work to check the levels of:

• B-human chorionic gonadotropin
• Rh factor
• Progesterone
• Hemoglobin

A transvaginal ultrasound may be used to check on the development of your embryo. Measurements may be taken of the gestational sac (large cavity of fluid surrounding the embryo), yolk sac (the front part of the embryo), and embryo to gauge the health and progress of your pregnancy. Smaller than normal growth may indicate that pregnancy loss is either possible or imminent.

Complications

While most bleeding in early pregnancy is not necessarily bad, there are other causes of bleeding that could signal trouble.

Ectopic Pregnancy

One cause of bleeding in early pregnancy that is not normal is an ectopic pregnancy. An ectopic pregnancy occurs when the fertilized egg implants somewhere other than the uterus wall, typically in one of the fallopian tubes.

Vaginal bleeding is sometimes the only sign of an ectopic pregnancy. Other symptoms may include abdominal, pelvic, or shoulder pain. 

While there have been rare cases where ectopic pregnancies were carried to term, most are fatal to the embryo. The structure housing the embryo can rupture in weeks as it grows. This can put you at risk of internal bleeding or other complications. You may also experience abdominal, pelvic, or shoulder pain with an ectopic pregnancy.

An ectopic pregnancy is a medical emergency, as medications or even surgery may be required to repair the damage from a rupture.

Molar Pregnancy

Molar pregnancy is an abnormal pregnancy that occurs when there is a problem with the growth of the placenta. In about one in 1,000 pregnancies, a genetic error can occur during fertilization and lead to a molar pregnancy.

Molar pregnancies form tumors rather than embryos, and are one of the causes of early pregnancy loss. They can appear with:

• Bright red bleeding
• Dark brown bleeding
• Cramping
• Nausea
• Vomiting
• Abdominal pain or pressure

Subchorionic Hemorrhage

Subchorionic hemorrhage is caused by a type of blood clot that forms between the placenta and the wall of the uterus. There are no treatments for this condition, but it also doesn't mean a pregnancy will end. In most cases, these clots are only detected with an ultrasound after heavier periods of bleeding. While these clots can result in pregnancy loss, in most cases the pregnancy can continue without further complications.

Summary

Light bleeding during early pregnancy is normal. However, it's still important to check with your obstetrician-gynecologist if you experience any bleeding while pregnant. They can make sure your bleeding is not caused by a problem with your pregnancy or an underlying condition.

A Word From Verywell

Pregnancy can be an exciting time, but it is also full of unknowns and worries, especially if it is your first pregnancy. If you experience light bleeding early in your pregnancy, there is probably nothing to worry about. Some bleeding, particularly after implantation, is normal. It's still important, though, to keep your obstetrician-gynecologist informed. If your bleeding becomes heavy or occurs with cramping or pain, call your healthcare provider immediately.