Somewhere around 30% of all pregnant women have some sort of bleeding during pregnancy, most commonly in the first trimester. Although miscarriage is one possible reason for first-trimester bleeding, it isn't the only explanation. Here are the most common reasons for first-trimester spotting or bleeding; remember that if you yourself are having bleeding, a visit to your doctor is the best way to determine the reason.
Implantation bleeding or spotting is light bleeding that occurs in some women around the time that the baby implants in the uterus, which is usually about eight to 12 days after conception. Because of that timing, implantation bleeding can sometimes be confused with a menstrual period.
Decidual bleeding is a type of light bleeding that can occur at intervals in early pregnancy around the times that a woman would have expected her menstrual period. Decidual bleeding is not a true menstrual period, but it is the most common reason why some women who report having had "periods" during pregnancy.
3. Increased Cervical Sensitivity
Blood flow to the cervix increases as a result of the hormonal changes of pregnancy, and this can lead to brief spotting after sex or after vaginal examinations and pap smears.
Bleeding or spotting can sometimes be a symptom of a bacterial infections of the vagina or cervix. These are especially important to treat during pregnancy, since there's evidence that some infections might increase the risk of second-trimester miscarriage or preterm birth.
A subchorionic hematoma is bleeding under the placenta. Subchorionic hematoma can sometimes end in miscarriage, but most often the bleeding goes away over time.
Vanishing twin is the term for a twin pregnancy in which one of the two babies is miscarried while the other remains viable.
Threatened miscarriage is a nonspecific term for when you have bleeding during pregnancy, but your cervix is still closed and there is no clear evidence that you are having a miscarriage (such as falling hCG levels). A threatened miscarriage can ultimately go on to be a viable pregnancy or may end in miscarriage.
Light bleeding in early pregnancy can be a warning sign of ectopic pregnancy, even though you might not have other ectopic pregnancy symptoms yet, so it's a good idea to see your doctor to rule out ectopic pregnancy.
Sadly miscarriage is an all-too-frequent explanation for early pregnancy bleeding, but it's not always obvious whether bleeding is caused by a miscarriage or something else, so see your doctor to be sure.