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Reasons for bleeding in early pregnancy

Posted on Wednesday, August 31, 2016 in Other Information & Resources

spotting bleeding in early pregnancy

Advertisers never use the colour red in advertising campaigns for sanitary products. It is more palatable for us to watch a beaker of blue solution being poured over the next ultra-thin product on the market than it’s red counterpart. We simply don’t like to be reminded that real blood is involved.

Red is also the colour you dread to see when you are pregnant.

There are a number of reasons why woman may spot in pregnancy, other than miscarriage.

I have included some links at the bottom of this page for more info, but here is a good summary of the information as I have found it:

  1. Cervicitis
    This is a condition in which the delicate cells at the mouth of the womb (or the cervix) bleed due to the mechanical action of intercourse, the alteration of acidity in the vagina (pH), or the effects of infections on these cells. There are two causes of Cervicitis:**

    • Ectopy (ectropion). With the hormonal changes of pregnancy, the fragile internal cells peek out a bit onto the external portion of the cervix, which is a harsher environment for them. Normally nestled deeply away from sexual activity and the acidity of the vagina, they can now be battered both chemically and mechanically. They’re easily damaged, causing bleeding. Of course, we’re not talking about a whole lot of bleeding — merely what is perceived as spotting. It must also be noted that these cells don’t normally bleed with sex –there is usually a predisposing condition, such as cervicitis. When these internal cervical cells are brought to a more external position, this is called ectopy.
    • Infection. Cervicitis is inflammation due to infection. Yeast is the most common culprit, and a simple prescription or even over-the-counter cream can end this concern quickly. Other infections are more worrisome. Sexually transmitted diseases (STDs), such as gonorrhea, chlamydia, trichomonas, and Gardnerella can do the same, so a microscopic evaluation is the best approach rather than just assuming it’s yeast. Some infections may be silent for years, meaning that even though there is no question of fidelity in a couple, there may have been an infection long before they even met each other; because of this, cultures for STDs have become standard in all pregnancies.

  3. Retrochorionic Bleeding.
    Sometimes bleeding occurs behind the conceptus inside the uterus. This is known as retrochorionic bleeding. Some blood will usually track down through the cervix and into the vagina. A speculum examination will often reveal blood tracking into the vagina through the cervical canal and a sonogram will reveal the presence of a retrochorionic blood clot. Although such bleeding can in some cases progress to an inevitable miscarriage, it often abates, and over time, the blood clot in the uterus absorbs and the pregnancy continues normally. Treatment involves careful observation, avoidance of aspirin and other non steroidal anti-inflammatory medications (NSAIDs), bed rest, and avoidance of vaginal penetration until the condition stabilizes.*

  5. Cervical Polyps.
    Harmless small polyps can also cause bleeding. These are overgrowths of benign tissue, probably owing their existence to estrogen levels that made them grow.**

  7. Implantation Bleeding.
    In the past it’s been thought that an egg eroding into the uterine lining would cause bleeding at the time because of a burrowing effect. It’s doubtful whether there’s any bleeding when this happens, and if so, it’s too small an amount to notice. The myth persists because there are bleeding episodes in which no cause is ever identified and in which the pregnancy goes on successfully to term. Such a mystery that starts off so menacingly but ends so well begs for an explanation that must include a natural process. Implantation makes sense under these criteria but can’t be proven.**

  9. Decidual Tissue.
    Sometimes a small piece of tissue becomes loose and disintegrates through some unknown cause, causing spotting. It’s usually a hormonally stimulated collection of menstrual-like tissue that can often be confused with a miscarriage. If it’s just tissue debris, it can mean nothing. If it’s actual tissue of the pregnancy (fetal or placental), then there should be serious concern, because now this “threatened miscarriage” is re-labeled as “incomplete miscarriage.” No one knows why such a phenomenon occurs, but it is harmless… The stabilization of the uterine lining depends on estrogen and progesterone. It’s possible that there are lags in the amounts of hormones so that lining not involved with implantation loses its grip and sheds… Such shedding of only decidual tissue has had no impact on whether a pregnancy will miscarry. The tissue is termed “decidualized,” because of the pregnancy-like effect on it at the hands of estrogen.**

  11. Subchorionic bleed.
    Subchorionic, or perigestational, hemorrhage is present in approximately 20% of women presenting with a threatened abortion, and is the most common cause of bleeding in normal IUPs (intrauterine pregnancy), usually presenting in the late first trimester. On US (ultrasound), these appear as either hyperechoic or hypoechoic, depending upon the age of the blood products. Most often these are not associated with any significant clinical sequelae, particularly if fetal cardiac activity is present. Large bleeds, defined as involving more than 2/3 the circumference of the gestational sac, are more likely to result in pregnancy failure. For smaller hematomas, no size thresholds have been confirmed to be prognostic, although this finding is a risk factor for subsequent pregnancy complications.******

  13. Bleeding occurs more often in women who have been through fertility treatment. This is probably due to the fact that many of them have transferred more than one embryo. The loss of either one or both embryos may result in bleeding.

  15. Having sexual intercourse during pregnancy does not have any adverse outcomes. However it would be sensible to avoid sex until the bleeding has completely stopped because of the risk of infection.***

  17. Approximately 30% of women will spot or bleed at some stage during their pregnancy. In one study with 4510 participants, 1204 (27%) reported some first-trimester vaginal bleeding or spotting, and 517 miscarriages were observed. Eight percent of those with bleeding reported heavy bleeding episodes. Women who reported heavy bleeding (n=97) had nearly three times the risk of miscarriage compared to women without bleeding during the first trimester.****

  19. Spotting or light bleeding episodes, especially those without pain and lasting only a day or two, do not increase the risk of miscarriage above baseline risk (i.e. the risk for women with no bleeding).****

  21. Bleeding prevalence is highest around gestational week 5–8. The timing of this peak coincides with the timing of important phases of placental development. A hormonally functional placenta is required for the luteal to placental shift in progesterone production that occurs around gestational week 7. Additionally, around the 10th week of pregnancy, the trophoblast blockage of the spiral arteries breaks down, remodeling of the arteries occurs, and the resulting blood flow to the developing placenta dramatically increases the oxygen tension. Premature onset of maternal-fetal circulation may expose the placenta and fetus to harmful levels of oxidative stress. Heavy bleeding during this time in pregnancy may be indicative of an underlying defect in placental development.****

  23. In another large study (4539 participants), approximately one-fourth of participants (n=1207) reported bleeding (n=1656 episodes), but only 8% of women with bleeding reported heavy bleeding. Of the spotting and light bleeding episodes (n=1555), 28% were associated with pain. Among heavy episodes, 54% were associated with pain. Most episodes lasted less than 3 days, and most occurred between gestational weeks 5–8. Twelve percent of women with bleeding and 13% of those without experienced miscarriage.
    Consistent with the hypothesis that bleeding is a marker for placental dysfunction, bleeding is most likely to be seen around the time of the luteal-placental shift.*****

  25. The term “threatened abortion” applies to any pregnancy of less than 20 weeks with abnormal bleeding, pain or contractions, with a closed cervix. Bleeding occurs in up to 27% of pregnancies, with the subsequent risk of miscarriage approximately 12%.******

  27. Bright red blood suggests that it is fresh, whereas brown blood suggests that it is stale blood that is tracking down. If bleeding becomes bright red or heavier get in touch with the EPAU or the Emergency Room for advice.***


Human Chorionic Gonadotropin (hCG)

If you experience bleeding in early pregnancy, you may have blood taken to check your beta hCG (human Chorionic Gonadotropin) levels. Typically this involves taking two blood tests, exactly 48 hours apart. You may have heard that hCG levels should double every 48 hours, although the truth is not as straightforward as this. In actual fact the higher your hCG levels rise, the slower their doubling rate becomes:

As your pregnancy develops, the increase (of hCG) slows down significantly. Between 1,200 and 6,000 mIU/ml serum, the hCG usually takes about 72-96 hours to double, and above 6,000 mIU/ml, the hCG often takes over four or more days to double. It makes little sense to follow the hCG values above 6,000 mIU/ml as at this point the increase is normally slower and not related to how well the pregnancy is doing. hCG levels rise during the first 6 to 10 weeks of pregnancy then decline slowly during the second and third trimesters.

Normal hCG doubling times:

  • Under 1,200 mIU/ml
  • 1200-6000 mIU/ml
  • Over 6,000 mIU/ml
  • Between 30 and 72 Hours
  • Between 72 and 96 Hours
  • Over 96 Hours


Signs which may indicate an early miscarriage:

Please remember that many women experience heavy bleeding and/or cramping and go on to have perfectly healthy babies. However you need to investigate any bleeding with your Early Pregnancy Unit or doctor. Here are some signs to look out for:

Symptoms of early miscarriage

  • Bleeding – light bleeding early in pregnancy is fairly common, and does not mean you will have a miscarriage. (It can include:):
    • Brown discharge: this may look like coffee grounds. This “discharge” is actually old blood that has been in the uterus for a while and is just coming out slowly.
    • Spotting, bright red bleeding or clots
  • Passage of tissue through the vagina
  • A gush of clear or pink vaginal fluid
  • Abdominal pain or cramping
  • Pregnancy symptoms, such as breast tenderness and nausea, begin to go away
  • Dizziness, lightheadedness, or feeling faint

If you have any symptoms of a miscarriage, you should contact a doctor right away to have an evaluation. It will be important to have an ultrasound exam to look into the uterus to see if the pregnancy is normal or you are having a miscarriage. Even if you think you passed the entire pregnancy and are feeling better, you should see a doctor. Sometimes, passing tissue occurs with an ectopic pregnancy (pregnancy outside of the uterus) which can be life-threatening if not diagnosed early.

Types of early miscarriage

Early miscarriage is a non-medical term for lots of different types of events that might or might not actually result in pregnancy loss. The types of miscarriage include the following:

  • Threatened Miscarriage: Spotting or bleeding in the first trimester in which the patient and the doctor are not yet sure if the pregnancy will miscarry or not.
  • Complete Miscarriage: the entire pregnancy is passed from the uterus, most commonly with bleeding and cramping, and no additional treatment or observation is needed.
  • Incomplete Miscarriage: the pregnancy is definitely miscarrying, but only some of the pregnancy tissue has passed. The tissue that is still in the uterus will eventually pass on its own. Some women may need emergency treatment if there is also heavy vaginal bleeding. Otherwise, women can use medicines to cause the rest of the tissue to pass or simply wait for the rest of the tissue to pass from the uterus.
  • Anembryonic Gestation: with this type of miscarriage, the pregnancy implanted but the embryonic tissue (the part of the pregnancy that will develop into a fetus) never developed, or started to develop and then stopped.
  • Embryonic or fetal demise: with this type of miscarriage, the early embryo (or fetus once 10 weeks pregnant) stops developing and growing.
  • Missed abortion: This is an uncommon type of miscarriage today. With a missed abortion, the pregnancy stops developing but the pregnancy tissue does not pass out of the uterus for at least 4 weeks. Sometimes, dark brown spotting or bleeding occurs, but there is no heavy bleeding.
  • Septic Miscarriage: some miscarriages occur with an infection in the uterus. This is a serious condition that requires urgent treatment to prevent shock and death. With septic miscarriage, the patient usually develops fever and abdominal pain and may have bleeding and discharge with a foul odour. Antibiotics and suction evacuation of the uterus are important to start as quickly as possible.

Courtesy UC Davis


Here are some links and articles related to this post:
  1. Bleeding in Early Pregnancy: Am I Going to Miscarry? Sher Fertility.*
  2. Bleeding in the First Trimester.**
  3. Crown rump length.
  4. Fetal pole.
  5. First Trimester Scans.
  6. First Trimester Ultrasound Notes for Trainees (downloadable pdf). Compiled by Dr. Phurb Dorji, Auckland University of Technology.
  7. Gestational sac.
  8. Gestational sac. Wikipedia.
  9. hCG Calculator and hCG Levels Chart Tool.
  10. Human chorionic gonadotropin. Wikipedia.
  11. Threatened Miscarriage (downloadable pdf). Coombe Women and Infants University Hospital.***
  12. Ultrasound of Early Pregnancy (downloadable pdf). Creighton University School of Medicine.
  13. Ultrasound of Fetal Biometrics and Growth (downloadable pdf). Creighton University School of Medicine.
  14. Understanding Early Miscarriage. Department of Obstetrics and Gynecology, UC Davis Health System.
  15. What is Fetal Pole?
  16. Yolk sac.
  17. Yolk sac. Wikipedia.
  1. Hasan, R; Baird, D; Herring, A; Olshan, A; Jonsson Funk, M; Hartmann, K. (2009). Association Between First-Trimester Vaginal Bleeding and Miscarriage. Obstetrics & Gynecology. Oct 2009; 114(4), 860–867.****
  2. Hasan, R; Baird, D; Herring, A; Olshan, A; Jonsson Funk, M; Hartmann, K. (2010). Patterns and predictors of vaginal bleeding in the first trimester of pregnancy. Ann Epidemiol. 2010 Jul; 20(7), 524–531.*****
  3. Lane, B; Wong-You-Cheong, J. (2014). Imaging of vaginal bleeding in early pregnancy. Applied Radiology. 2014, September 5th.******
  4. Morin, L; Van den Hof, M. (2005). Ultrasound Evaluation of First Trimester Pregnancy Complications (downloadable pdf). Journal of Obstetrics and Gynaecology. Canada 2005; 27(6) 581–585.
  5. Thach, T.S. (2009). Thach TS. Progestogen for preventing miscarriage : RHL commentary (last revised: 2 February 2009). The WHO Reproductive Health Library; Geneva: World Health Organization.


Much of this information in this post was originally published in an earlier post under the category “IVF using an Egg Donor”, entitled What’s the Bleeding Story?