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What Is Decidual Bleeding?

Jessica Ellis
Updated Mar 03, 2024
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Decidual bleeding is a term for a partial shedding of the uterine lining during the first few months of pregnancy. This bleeding can be similar to a menstrual period and can occasionally prevent women from realizing that they are pregnant until other signs develop. Although this kind of bleeding is usually harmless, most experts recommend that pregnant women inform their doctors about any form or amount of vaginal bleeding as it can be a sign of more serious conditions.

During early pregnancy, quick hormonal shifts in the body can cause ovulation or the thickening of the uterine lining despite the presence of a fertilized egg. Around the time of a women’s normal menstrual period, the lining can shed, resulting in bleeding. For some women, the amount of blood released can resemble an normal period. For this reason, some experts recommend that anyone with other pregnancy signs, such as regular nausea, increased breast size or tenderness, or sudden weight gain, take a pregnancy test even if menstrual cycles appear normal. If an over the counter test proves positive despite the presence of bleeding, consider consulting a doctor for a more accurate confirmation of pregnancy.

Decidual bleeding is sometimes confused or used synonymously with implantation bleeding, another phenomena of early pregnancy. Implantation bleeding is characterized as a light spotting that is the result of the egg implanting in the uterus. Like decidual bleeding, implantation bleeding can cause women to believe they are not pregnant and are experiencing a normal menstrual period. Because of this similarity, and the fact that both types of bleeding are considered largely harmless, both implantation and decidual bleeding are often referred to collectively as first-trimester bleeding.

In most cases, this condition is not harmful to either the mother or fetus. Although figures vary, some experts suggest that harmless vaginal bleeding occurs in up to 30% of pregnancies. Most women who experience this type of bleeding during pregnancy go on to have healthy pregnancies and deliveries.

Despite the relative harmlessness of this type of bleeding, most experts urge that women experience any bleeding during pregnancy inform a health care provider immediately. Bleeding can be a sign of several conditions that can adversely affect health, such as cervical cancer, impending miscarriage, ectopic or molar pregnancies, or cervical or vaginal infections. If bleeding continues longer than a day or is heavy, a doctor may request an examination to check the health of both mother and fetus and rule out possible complications.

How Do I Know If I Have Decidual Bleeding?

Decidual bleeding presents differently for every woman because it looks and feels a lot like a normal period. Some women may experience minimal spotting while others have moderate bleeding, though most notice more clots than they get with a typical period. Women may also experience cramping and abdominal pain. 

The only way to know for sure that a woman is experiencing decidual bleeding instead of a normal period is to take a pregnancy test. It’s advisable to see a general physician or OB/GYN for evaluation to ensure that the woman and fetus are both healthy.

Women who experience heavy bleeding should see a physician as soon as possible. Excessive bleeding can be a symptom of other health conditions, like a vaginal infection, ectopic pregnancy, or early signs of miscarriage.

What Color Is Decidual Bleeding?

Decidual bleeding is typically light red to crimson, though some have brownish-colored blood. Women who experience other colors of discharge or who notice an odd or foul smell should seek medical attention as soon as possible to rule out other conditions.

How Long Does Decidual Bleeding Last?

Decidual bleeding can last anywhere from a few days up to a few weeks. It’s important to see a physician for evaluation and guidance, especially if the bleeding becomes heavy. 

How Often Does Decidual Bleeding Occur?

It can occur monthly, like a normal menstrual cycle. Since decidual bleeding is the uterine wall shedding, it looks and feels like a regular period. Consequently, decidual bleeding can prevent women from knowing they are pregnant for the first several months. 

How Do You Stop Decidual Bleeding?

There is no treatment because decidual bleeding usually resolves itself when the uterine wall stops shedding. Depending on the individual and their underlying conditions, a physician may prescribe hormonal treatments to correct an imbalance.

What Is Decidual Cast?

Decidual cast, or membranous dysmenorrhea, refers to the body shedding a large, solid clump of tissue. During a normal menstrual cycle, the body gradually sheds the uterine lining over several days, but with a decidual cast, it happens all at once. The body passes the entire lining in one piece, so it looks like a replica of the woman’s uterus.

Passing such a large amount of solid tissue can be extremely painful with overall bodily discomfort, vaginal bleeding, and cramping. However, once the cast passes, the symptoms should resolve quickly. The decidual cast should appear shiny and fleshy with pinkish coloring with mucus and blood mixed in with the tissue. 

While decidual bleeding is common, a decidual cast is extremely rare. Due to the lack of known cases, there is little information about the condition or what causes it to happen. Currently, the medical community believes that ectopic pregnancy and hormonal birth control pills are the leading causes.

What Should You Do If You Pass a Decidual Cast?

Passing a decidual cast is extremely rare, but it’s important to not panic. Contact a physician or go to an urgent care facility soon. It’s also a good idea to collect the tissue for testing to confirm a diagnosis and check pathology. 

Women taking contraceptives should continue to take them to avoid other complications. 

Does Decidual Cast Mean Miscarriage?

Though the symptoms appear similar, a decidual cast does not necessarily mean a woman is having a miscarriage. Most reported cases are women who were on contraceptives and not pregnant at the time of the passing. However, since membranous dysmenorrhea typically looks like a gestational sac, a medical team needs to rule out a miscarriage. 

Notably, other conditions can cause women to pass large, solid masses, including neoplasms and polyps. Younger women and girls have also had sarcoma botryoides and fibroepithelial polyps.

Can You Prevent a Decidual Cast? 

No, there is no way to prevent a decidual cast. It is a relatively rare condition that currently appears to have some association with certain contraceptives. However, there’s not enough information to suggest women should stop taking their birth control pills to avoid passing a decidual cast. 

Can You Still Get Pregnant With a Decidual Cast?

Given the lack of cases and subsequent research, it is unknown whether or not a woman can still get pregnant during or after passing a decidual cast.

Frequently Asked Questions

What is decidual bleeding?

Decidual bleeding is a form of vaginal bleeding that may happen in a pregnant woman's first trimester. It differs from a usual monthly cycle in that it is often lighter, lasts longer, and is frequently accompanied by additional symptoms, including cramps, nausea, and lower back discomfort. This sort of bleeding, which may either signify a healthy pregnancy or a miscarriage, is considered to be brought on by hormonal changes during pregnancy.

How does decidual bleeding differ from a regular menstrual period?

Decidual bleeding is lighter and lasts longer than a typical menstrual cycle. Other symptoms, including cramps, lower back discomfort, and nausea, are also often present. Decidual bleeding, which might indicate a healthy pregnancy or a miscarriage, is thought to be brought on by variations in hormone levels throughout pregnancy.

How long does decidual bleeding last?

Decidual bleeding may continue for a few days or for a few weeks. While it is usually milder than a normal menstrual period, it may also include additional symptoms, including cramps, nausea, and lower back discomfort.

Is decidual bleeding always a sign of a miscarriage?

Decidual bleeding can be indicative of a miscarriage, but this isn't always the case. If you experience decidual bleeding, it is imperative that you see a healthcare professional. They will determine if it is an indication of a miscarriage or a typical pregnancy.

What should I do if I experience decidual bleeding?

It is crucial that you get in touch with your healthcare provider right away if you experience decidual bleeding. It may be necessary to do more tests or examinations to identify the source of the bleeding, so it's important to follow your doctor's recommendations and take good care of yourself during this time.

The Health Board is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Jessica Ellis
By Jessica Ellis , Writer
With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica Ellis brings a unique perspective to her work as a writer for The Health Board. While passionate about drama and film, Jessica enjoys learning and writing about a wide range of topics, creating content that is both informative and engaging for readers.

Discussion Comments

By anon963542 — On Jul 30, 2014

I'm having the same issues. I can feel the babies move and kick. I have a monitor and have heard heartbeats with 142 to 145 beats per minute, but have continued to have a negative UPT and blood test at the doctor's office, I can't get them to do an ultrasound. I requested one but they won't do it. How did you get them to do it? Can you please give me some advice?

By hezekin25 — On Jul 29, 2014

Well, I have a story and I know no one can help me but going to the doctor. It's rather interesting.

I have had a tubal for nine years and now I feel pregnant. I do know that it is possible but I just can't believe it. I had a cycle, then the next one was late then the next one was short. I have gained weight, have breast tenderness/sharp pain in breast, colostrum, fatigue, some nausea and am moody. I have taken a HPT and they all have been negative. I took a blood test and it was negative so I am totally ignoring it.

Now that I have read tons of stories, I'm not so sure that the tests are right. Right now, I am just playing the waiting game. I don't like looking like a fool so when the blood test was negative I just said forget it. I do feel very pregnant and I have two kids so I know what this feeling is. I am just a little upset with the weight gain and possibly not being pregnant so I guess I will just keep waiting and keep you all posted.

By anon339768 — On Jun 26, 2013

@anon333781: I'm 20 and I had the exact same problem. Although yours started for two days then stopped then for two days again, mine was just one day then stopped for two days then came for one day, but when I say day, it's actually the one time out of like five when I go to the bathroom that there was pinkish when I wiped. Could I be pregnant?

By anon333781 — On May 07, 2013

I am 22 and have been engaged for three years. My fiance and I are trying to conceive. Last week, I had what I thought was my period. I bled for like two days, then it stopped and started for two more days, then stopped then started for another day.

Now when I go to the bathroom and wipe, there is a pinkish color on the toilet paper. I've take four home pregnancy tests and they've all come back negative. I don't know if I'm experiencing implantation or if it's something more serious. Does anyone have any thoughts or suggestions?

By anon332091 — On Apr 26, 2013

Personally, I don't know anything about it, but I definitely went to the doctor's office for a pregnancy test and received a negative result. After sounding like a lunatic, I'm sure, and insisting on a blood test, after four months of regular periods, a fifteen pound weight gain, and nausea I found out I was about five months pregnant.

By anon323011 — On Mar 02, 2013

Can anyone give me some advice about my problem? I used to have a regular period every month, but then last month (February) I was supposed to have my menstrual period the last week of the month. Then it was more than a week that I didn't have my period, so I decided to get a pregnancy test and it had two lines which means it was positive.

Two days after I found out that I'm positive on that pregnancy test, on the second day of March, I had some bleeding, but it's just like a few drops of blood and not too heavy, unlike a regular period. But I am still confused about it, because on the pregnancy test it showed that I'm positive but then suddenly I had bleeding. I feel so depressed about it. Please help me.

By anon271467 — On May 26, 2012

Before my periods, I have a very nauseated, sleepy feeling. I had my periods two days late and I just had a very heavy bleeding for only one day with a large blood clot but it stopped at night.

Then I had very light bleeding on the second and third day which cannot be counted as bleeding. On the fourth day, I started having a white discharge, and I also had a nauseated feeling. I want to sleep and am having back pain. What is this? The first day of my period was also painful. I'm married.

By anon259351 — On Apr 05, 2012

Yes, decidual bleeding can cause a false negative. I had a negative blood test at the doctor and they did and ultrasound and I was five months pregnant with a baby boy.

By anon226753 — On Nov 02, 2011

Why still consume alcohol when you are trying to conceive? That is silly. We know for a fact that alcohol reduces fertility and sperm count to begin with! Not even going to mention drug use!

By anon125104 — On Nov 08, 2010

Obviously jeancastle00 was talking in general. Why do you have to be so negative. She (or he) was simply stating a fact.

By anon109748 — On Sep 08, 2010

What do drugs and alcohol have anything to do with what anon94647 asked? And continuing? Was there an implied substance abuse issue or are we just making sure our own agendas are fulfilled?

By jeancastle00 — On Jul 11, 2010

@anon94647, I don't think that decidual bleeding will actually cause a false negative result in a pregnancy test but it has a psychological effect on the woman that is trying to determine her pregnancy status.

The vaginal discharge can be mistaken by the woman as her monthly menstrual discharge. This false sense of not carrying a child could result in a mother continuing to abuse drugs or alcohol even though she is pregnant.

By anon94647 — On Jul 09, 2010

So can decidual bleeding cause you to have a false negative test?

Jessica Ellis

Jessica Ellis


With a B.A. in theater from UCLA and a graduate degree in screenwriting from the American Film Institute, Jessica Ellis...
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