Spotting in early pregnancy is common for many women and usually not a cause for concern. However, in some instances, it may occur as a symptom of a pregnancy complication.
About a quarter of pregnant women experience bleeding during the first trimester. Although bleeding is a possible sign of early pregnancy loss, it does not mean that this will happen. Several other conditions and factors, including normal hormonal shifts, may cause spotting in early pregnancy.
The most common causes of spotting in early pregnancy include:
A subchorionic hematoma is sometimes called subchorionic hemorrhage. This happens when blood builds up near the chorion, which is the fetal membrane next to the placenta. The bleeding may also appear between the uterus and the placenta.
Subchorionic hematoma is a common pregnancy complication with various studies estimating the prevalence between 1.3% and 62% among different groups of pregnant women.
A subchorionic hematoma is not a pregnancy loss. Many pregnant women with this type of bleeding have no further complications during their pregnancy.
A 2012 meta-analysis of nine research studies concluded that there was a link between subchorionic hemorrhage and higher risk of pregnancy loss and preterm labor.
However, a 2013 observational study of 1,115 women that included 142 with a subchorionic hematoma found no significant increase in the risk of pregnancy complications.
In an ectopic pregnancy, a fertilized egg implants outside of the uterus, often in the fallopian tubes. A woman may still have pregnancy symptoms or get a positive pregnancy test. The pregnancy, however, cannot survive. If it continues to grow, it can rupture and cause life threatening bleeding or a dangerous infection.
An ectopic pregnancy can cause spotting as the pregnancy grows. If the pregnancy ruptures, it can cause life threatening internal bleeding that may get progressively heavier over several hours.
The cervix, the doughnut-shaped entry to the uterus, increases its blood supply during pregnancy. This means it is more likely to bleed from irritation, such as after sex or a pelvic exam. Light spotting after any form of vaginal penetration is a possible sign of cervical bleeding.
Cervical bleeding is not dangerous and usually stops on its own within a few hours. The blood is typically red or brown, and the bleeding minimal.
Very rarely, a serious injury to the cervix, such as from an assault or trauma, might cause more severe cervical bleeding. These injuries can cause infections and other serious complications. It is important to see a doctor following any traumatic injury to the cervix or vagina.
For many pregnant women, bleeding triggers fears of pregnancy loss. A 2010 study of 4,539 pregnant women found that 26.7% experienced bleeding at some point during their pregnancies, but only 12% had a pregnancy loss. These figures suggest that less than half of people who bleed during pregnancy have a pregnancy loss.
About two-thirds of people who do have a pregnancy loss report bleeding. As such, bleeding is a symptom that a pregnant person should not ignore. Any pregnant woman who has concerns about their pregnancy should speak to a doctor about risk factors and how to minimize them.
Around the 7th week of pregnancy, a luteal-placental shift happens. This is when the placenta develops enough to begin producing hormones that sustain the pregnancy. Before this change, the corpus luteum — a group of cells that forms during ovulation — produces pregnancy hormones.
This hormonal change sometimes triggers a temporary drop in the hormone progesterone. This shift may cause spotting, or even bleeding as heavy as a period. As long as the placenta begins producing enough progesterone, the pregnancy can safely continue, and a woman will not have a pregnancy loss.
A doctor or other healthcare provider may do numerous tests to diagnose bleeding. These may include:
An ultrasound can diagnose a subchorionic hematoma. It can also tell a healthcare provider the location of the pregnancy, helping in the detection of an ectopic pregnancy.
After about the 6th week of pregnancy, an ultrasound can measure the viability of the pregnancy. If the embryo is growing correctly, and there is a sufficiently strong heartbeat, this suggests that the pregnancy will continue and the risk of pregnancy loss is low.
An ultrasound can also examine other pelvic organs to check for causes of bleeding. For example, an ovarian cyst may cause bleeding.
Blood tests can measure levels of the pregnancy hormone hCG. Low hCG may suggest that a pregnancy is not developing correctly or is in its early stages.
Some healthcare providers also check progesterone levels. Low progesterone may cause temporary bleeding, while very low progesterone may be a sign of an abnormal pregnancy.
While many women who experience bleeding have healthy pregnancies, it is important never to treat bleeding as usual. Bleeding can be a critical symptom of several pregnancy-related symptoms, and prompt treatment for conditions such as ectopic pregnancy can save lives.
Implantation happens when a fertilized egg embeds in the lining of the uterus. This marks the beginning of pregnancy. Some women notice spotting shortly after implantation. However, the body does not begin producing hCG until after implantation.
A woman is not pregnant until after implantation, and a pregnancy test cannot usually detect pregnancy until several days after implantation. So, bleeding that appears after a woman already knows she is pregnant is not implantation bleeding.
Implantation bleeding is usually brown. Some women may mistake the bleeding for their monthly period because it usually occurs around the time a woman expects her period.
The flow of implantation bleeding is often lighter and shorter than a period, so women who experience unusual bleeding after having sex should consider the possibility of pregnancy.
Speak to a doctor about any bleeding early in pregnancy. While the bleeding may be harmless, it is impossible to diagnose its cause without blood work, an ultrasound, or other diagnostic tests.
Bleeding from a ruptured ectopic pregnancy can endanger the life of the mother. While many pregnancy losses pass on their own, some require treatment to prevent excessive bleeding and infection.
Prompt medical care can be lifesaving. Even when there is no serious problem, the right care can offer peace of mind.
If a pregnant woman experiencing spotting has Rh-negative blood, a doctor may prescribe RhoGAM. This treatment can help prevent a condition known as erythroblastosis fetalis.
If a woman experiences light bleeding at any time, they should contact a midwife, doctor, or another healthcare provider.
A woman should visit an emergency room if:
- they develop a fever
- bleeding gets heavier over several hours
- bleeding is heavy, similar to a period
- there are large clots in the blood
- they have cramps
- there is severe pain in the abdomen
- they feel dizzy or light-headed
Many women panic when they bleed during pregnancy, especially if they have a previous history of miscarriage. Seeking prompt care is the fastest way to ease anxiety and get clear answers.
It is not advisable for people to try to self-diagnose bleeding or assume that bleeding means a pregnancy loss. A few quick tests can usually diagnose the cause, and prompt treatment can prevent possible complications.