Bleeding during pregnancy is common, especially during the first trimester, and usually it's no cause for alarm. But because bleeding can sometimes be a sign of something serious, it's important to know the possible causes, and get checked out by your doctor to make sure you and your baby are healthy.
About 20% of women have some bleeding during the first 12 weeks of pregnancy. Possible causes of first trimester bleeding include:
Implantation bleeding. You may experience some normal spotting within the first six to 12 days after you conceive as the fertilized egg implants itself in the lining of the uterus. Some women don't realize they are pregnant because they mistake this bleeding for a light period. Usually the bleeding is very light and lasts from a few hours to a few days.
Miscarriage. Because miscarriage is most common during the first 12 weeks of pregnancy, it tends to be one of the biggest concerns with first trimester bleeding. However, first trimester bleeding does not necessarily mean that you’ve lost the baby or going to miscarry. In fact, if a heartbeat is seen on ultrasound, over 90% of women who experience first trimester vaginal bleeding will not miscarry.
Other symptoms of miscarriage are strong cramps in the lower abdomen and tissue passing through the vagina.
Ectopic pregnancy. In an ectopic pregnancy, the fertilized embryo implants outside of the uterus, usually in the fallopian tube. If the embryo keeps growing, it can cause the fallopian tube to burst, which can be life-threatening to the mother. Although ectopic pregnancy is potentially dangerous, it only occurs in about 2% of pregnancies.
Other symptoms of ectopic pregnancy are strong cramps or pain in the lower abdomen, and lightheadedness.
Molar pregnancy (also called gestational trophoblastic disease). This is a very rare condition in which abnormal tissue grows inside the uterus instead of a baby. In rare cases, the tissue is cancerous and can spread to other parts of the body.
Other symptoms of molar pregnancy are severe nausea and vomiting, and rapid enlargement of the uterus.
Additional causes of bleeding in early pregnancy include:
- Cervical changes. During pregnancy, extra blood flows to the cervix. Intercourse or a Pap test, which cause contact with the cervix, can trigger bleeding. This type of bleeding isn't cause for concern.
- Infection. Any infection of the cervix, vagina, or a sexually transmitted infection (such as chlamydia, gonorrhea, or herpes) can cause bleeding in the first trimester.
Abnormal bleeding in late pregnancy may be more serious because it can signal a problem with the mother or baby. Call your doctor as soon as possible if you experience any bleeding in your second or third trimester.
Possible causes of bleeding in late pregnancy include:
Placenta previa. This condition occurs when the placenta sits low in the uterus and partially or completely covers the opening of the birth canal. Placenta previa is very rare in the late third trimester, occurring in only one in 200 pregnancies. A bleeding placenta previa, which can be painless, is an emergency requiring immediate medical attention.
Placental abruption. In about 1% of pregnancies, the placenta detaches from the wall of the uterus before or during labor and blood pools between the placenta and uterus. Placental abruption can be very dangerous to both the mother and baby.
Other signs and symptoms of placental abruption are abdominal pain, clots from the vagina, tender uterus, and back pain.
Uterine rupture. In rare cases, a scar from a previous C-section can tear open during pregnancy. Uterine rupture can be life-threatening, and requires an emergency C-section.
Other symptoms of uterine rupture are pain and tenderness in the abdomen.
Vasa previa. In this very rare condition, the developing baby's blood vessels in the umbilical cord or placenta cross the opening to the birth canal. Vasa previa can be very dangerous to the baby because the blood vessels can tear open, causing the baby to bleed severely and lose oxygen.
Other signs of vasa previa include abnormal fetal heart rate and excessive bleeding.
Premature labor. Vaginal bleeding late in pregnancy may just be a sign that your body is getting ready to deliver. A few days or weeks before labor begins, the mucus plug that covers the opening of the uterus will pass out of the vagina, and it will usually have small amounts of blood in it (this is known as "bloody show"). If bleeding and symptoms of labor begin before the 37th week of pregnancy, contact your doctor right away because you might be in preterm labor.
Other symptoms of preterm labor include contractions, vaginal discharge, abdominal pressure, and ache in the lower back.
Additional causes of bleeding in late pregnancy are:
- Injury to the cervix or vagina
- Polyps
- Cancer
Because vaginal bleeding in any trimester can be a sign of a problem, call your doctor. Wear a pad so that you can keep track of how much you're bleeding, and record the type of blood (for example, pink, brown, or red; smooth or full of clots). Bring any tissue that passes through the vagina to your doctor for testing. Don't use a tampon or have sex while you are still bleeding.
Your doctor might recommend that you rest as much as you can and avoid exercise and travel.
You should expect to receive an ultrasound to identify what the underlying cause of your bleeding may be. Vaginal and abdominal ultrasounds are often performed together as part of a full evaluation.
Go to the emergency room or call 911 right away if you have any of the following symptoms, which could be signs of a miscarriage or other serious problem:
- Severe pain or intense cramps low in the abdomen
- Severe bleeding, with or without pain
- Discharge from the vagina that contains tissue
- Dizziness or fainting
- A fever of more than 100.4 or more degrees Fahrenheit and/or chills
People may worry if they notice clots in their menstrual blood, but this is perfectly normal and rarely cause for concern.
Menstrual clots are a mixture of blood cells, tissue from the lining of the uterus, and proteins in the blood that help regulate its flow.
Some medical conditions can cause large blood clots, often alongside heavy menstrual bleeding or period pains. People should see a doctor if they are concerned about their menstrual clots.
Share on PinterestBlood clots are a natural part of menstruation.
It might be surprising to see a thick glob of menstrual blood, but, in most cases, blood clots are a natural part of menstruation.
It does not usually mean that there is a problem, but sometimes it can be a sign of a health condition.
Blood clots are a natural part of the body’s defense mechanism. The thick, jelly-like texture of a menstrual clot helps prevent too much blood from escaping.
This is the same clotting function that happens elsewhere in the body is an injury to the tissue, such as a cut or laceration.
Menstrual clots generally occur when the flow is heavy. They are more common during the first 2 days of menstruation, which is typically the heaviest part of a period.
Clots can be bright in color, or a darker, deeper red. More sizeable clots may look black. Menstrual blood begins to appear darker and more brown toward the end of each period as the blood is older and leaving the body less quickly.
Clots happen when the uterine lining sheds increased amounts of blood. When the blood pools in the uterus or vagina, it begins to coagulate, much like it would on an open skin wound.
The consistency of menstrual blood varies both throughout the period and from one period to another.
People may experience a heavy flow containing menstrual clots one month, and a lighter flow with no clots the next month.
This variation is natural, and changes may occur due to diet and lifestyle factors.
During menstruation, the endometrial cells that line the uterus strip away and leave the body.
As this happens, the body releases proteins that cause the blood in the uterus to coagulate. This coagulation prevents the blood vessels in the uterine lining from continuing to bleed.
The blood that the body has already shed also contains these coagulation proteins.
When the flow is most substantial, the coagulation proteins within the blood may start to clump together, resulting in menstrual clots.
This generally occurs when menstrual blood pools in the uterus or vagina before leaving the body.
Although it is normal to have clots in the blood during menstruation, this symptom can sometimes signal a medical issue. It is advisable to seek medical advice if the clots:
- are larger than a quarter in size
- are very frequent
- occur with an abnormally heavy flow that requires a person to change their pad or tampon at least every 1–2 hours
- occur with significant pain
The following conditions may cause abnormal menstrual clots:
Uterine polyps or fibroids
A blockage in the uterus may stop it from contracting as it should, meaning that it cannot force the blood out as quickly as usual. The blood will leave the body more slowly so it will have more time to pool and form clumps.
The blockage can also cause a heavier flow, which results in more blood pooling.
Blockages may occur as a result of growths in the uterus. These include uterine polyps and fibroids, which are not cancerous but can cause other health issues without proper management.
Uterine polyps and fibroids consist of either endometrial or muscular tissue that grows in the uterine wall. They can cause symptoms such as:
- persistent lower back pain
- pain during sex, or dyspareunia
- feeling bloated
- fertility issues
- irregular spotting
Endometriosis
Share on PinterestEndometriosis can cause painful and heavy periods.
Endometriosis is a condition that causes the tissues of the uterine lining to grow outside of the uterus.
This abnormality can lead to several symptoms, which may be worse around the time of menstruation.
Symptoms of endometriosis often include:
- pain and cramping in the pelvis or lower back
- very heavy periods, or menorrhagia
- painful periods, or dysmenorrhea
- discomfort or pain during sex
- fertility issues
Adenomyosis
In people with adenomyosis, the uterine lining grows into the muscular wall of the uterus.
This can make the endometrial lining and uterine wall much thicker, which can lead to a much heavier flow during a period.
As a result, it is more likely that blood clots will appear in the menstrual blood.
Hormonal imbalances
The balance of hormones in the body is essential for maintaining a healthy uterus.
If the levels of specific hormones become unbalanced, many issues can occur, including heavy menstruation or clotting.
Pregnancy loss
During a miscarriage, or pregnancy loss, a person will usually pass a number of large clots, depending on the stage of the pregnancy.
Pregnancy loss can sometimes occur before a person knows that they are pregnant, so they may mistake an early miscarriage for a regular menstrual cycle.
Enlarged uterus
After pregnancy, a person’s uterus often remains somewhat larger than it was before. An enlarged uterus can also be due to structural issues, such as fibroids.
There will be additional space for the blood to pool in, which could lead to further clotting before it exits the body.
Bleeding disorders
Some bleeding disorders may be responsible for heavy menstrual flow, as they can affect the coagulation proteins that the uterine lining needs to stop menstrual bleeding.
Disorders such as platelet function disorder or von Willebrand’s disease (VWD) may cause abnormally heavy menstruation.
People who are experiencing very heavy menstrual bleeding or have clots larger than a quarter in their menstrual blood should see a doctor, especially if they have any of the signs or symptoms of the conditions mentioned above.
What is a heavy flow?
A person with heavy menstruation may have to change their pad, tampon, or menstrual cup more than once every 2 hours for part of their period. They may also need two pads at a time and may miss out on everyday activities due to their menstrual flow.
Anemia
People with very heavy periods have a higher risk of iron-deficiency anemia.
Anemia occurs when there are fewer red blood cells in the body than usual. Low iron levels can cause this because the body needs iron to make new healthy blood cells.
Other symptoms of iron deficiency include:
- general fatigue
- weakness
- shortness of breath
Anyone who is uncertain about their menstrual clots should see a doctor.
Share on PinterestA diet that includes iron-rich foods may help with menstrual blood clots.
To diagnose the cause of abnormal menstrual clots, a doctor may ask about signs and symptoms, order blood or imaging tests, carry out a physical examination, or a combination of these.
Finding out the cause will allow a doctor to recommend the most appropriate course of treatment.
Doctors may advise taking an iron supplement if they believe that someone is losing too much blood or may be at risk of anemia.
They may also suggest some actions that people can take at home, such as:
- staying hydrated with water
- avoiding aspirin, which may make bleeding worse
- eating a healthful diet that includes iron-rich foods
- doing regular physical activity
Medication
Doctors may prescribe hormonal medications to help balance the hormones and control heavy bleeding.
They may suggest using or changing a birth control method. Intrauterine devices (IUDs) containing progestin may reduce blood flow, and some birth control pills may also help.
Doctors may recommend taking nonsteroidal anti-inflammatory drugs (NSAIDs) during the period to help reduce symptoms, such as cramping, pain, and discomfort. The NSAIDs may also help with excessive bleeding.
People who prefer not to use hormone treatments may wish to try medications that control blood clotting instead. It is best to speak to a doctor about this.
Menstrual clots are normal and usually a symptom of heavy menstrual flow.
However, anyone who notices a pattern of heavy flow or heavy clotting alongside other symptoms should see a doctor.
There are a few different causes of abnormal menstruation. A doctor can help find effective ways to treat the underlying issues and control frequent or large menstrual clots.
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