Any amount of bleeding during pregnancy can be scary. However, it’s not always a sign that something is wrong. The Mayo Clinic reassures us that many women who experience bleeding during pregnancy go on to have healthy pregnancies! That being said, it’s important to understand the possible causes, be aware of your symptoms, and be in touch with your healthcare provider.


Today, we’re exploring the possible causes of bleeding during pregnancy and how you can get diagnosed and treated! Keep reading to learn more.

Bleeding vs. Spotting: How Much Bleeding is Normal?

The amount of bleeding you’re experiencing is important to note, as your doctor may ask if you’re bleeding or spotting.


  • Spotting, also called light bleeding, looks like a few drops of blood here or there. Your underwear won’t be soaked by spotting. While it isn’t usually a serious concern, you should alert your doctor so they can monitor your symptoms.

  • Bleeding. Bleeding is more than just a few drops of blood and usually points to a serious problem. If you need a pad just to keep the flow from ruining your underwear, contact your doctor as soon as possible.

What are the Possible Causes of Bleeding During Pregnancy?

As mentioned earlier, bleeding during pregnancy is very common and not always a cause for alarm. However, it’s important to communicate with your doctor regularly and keep track of your symptoms to prevent further complications. 

Bleeding During the First Trimester

According to the Cleveland Clinic, it’s normal to experience bleeding during the first trimester. Possible causes include:


  • Miscarriage (before 20 weeks). Miscarriages in the first trimester may start with light bleeding and get heavier as they progress. 


  • Cervical polyps. Cervical polyps are growths found in the cervix, which bleed due to the increased estrogen produced during pregnancy. Cervical polyps are common and usually benign, though 0.2 to 1.5% of cases are malignant. The National Library of Medicine states that “many women with polyps have successful pregnancies”.


  • Implantation bleeding. Implantation bleeding occurs when a fertilized egg attaches to the lining of the uterus. The bleeding is very light. Some women mistake it for a period or don’t notice it at all. According to the Mayo Clinic, it stops on its own and doesn’t require treatment. 


  • Subchorionic hematoma. Subchorionic hematomas occur when blood collects under the chorion membrane, which attaches the uterine wall to the amniotic sac, resulting in vaginal bleeding. The Cleveland Clinic states that most subchorionic hematomas “go away on their own without causing complications”. 


  • Molar pregnancy. The March of Dimes defines a molar pregnancy as “a tumor that develops in the uterus at the beginning of pregnancy”. If left untreated, it can be dangerous to the woman. Signs and symptoms of a molar pregnancy include vaginal bleeding or intense nausea and vomiting.


  • Ectopic pregnancy. An ectopic pregnancy occurs when the fertilized egg implants and starts to grow outside of the uterus, usually in the fallopian tube. If left untreated, it could cause a rupture where the egg has implanted.

Bleeding During the Second or Third Trimester

Bleeding during the second and third trimesters usually indicates serious problems. Call your healthcare provider immediately, as you may need emergency treatment. 


  • Miscarriage. Miscarriage after 20 weeks of pregnancy is also called a stillbirth. One of the most common symptoms is vaginal bleeding.


  • Placenta previa. Placenta previa is a problem during pregnancy in which the placenta covers the cervix, which can cause vaginal bleeding. The baby may need to be delivered via C-section if it doesn’t resolve on its own.


  • Placental abruption. Placental abruption occurs when the placenta separates from the uterus before delivery. This causes heavy bleeding in the mother and blocks the flow of oxygen and nutrients to the baby.


  • Uterine rupture. A uterine rupture is a life-threatening situation in which the uterus is torn along the scar from a C-section.


  • Incompetent cervix. An incompetent cervix is a rare occurrence in which the cervix dilates too soon, causing preterm labor.


  • Preterm labor. Preterm labor is labor that occurs after 20 weeks and before 37 weeks of pregnancy. It can cause bleeding, especially if the woman is also experiencing contractions, backaches, or pelvic pressure. 

Other Causes of Bleeding During Pregnancy

You can experience bleeding due to other reasons not directly related to pregnancy. Other possible causes are:


  • Sexually Transmitted Infections (STIs). STIs like chlamydia and gonorrhea can cause light bleeding during pregnancy.


  • Sex. Having sex while pregnant can cause you to bleed. It can be especially dangerous if you’ve had pregnancy complications in the past.


  • Internal exams. Procedures that require your healthcare provider to probe into the vagina, such as pelvic exams and transvaginal ultrasounds, may cause you to bleed.


While the causes listed above are commonly associated with bleeding during pregnancy, they may not be the cause for your specific situation. Contact your doctor to receive an accurate diagnosis. 

How Bleeding During Pregnancy is Treated

First, your doctor will perform an ultrasound to determine the cause of the bleeding. If the results are unclear, they may also perform a blood test, urine test, or an MRI. Once the cause of the bleeding has been discovered, they may advise you to: 


  • Get more rest and stay off your feet 
  • Avoid heavy exercise 
  • Refrain from lifting heavy objects
  • Avoid having sex until the bleeding stops


Bed rest, hospitalization, or surgery may be needed in severe circumstances.

Free Ultrasounds in San Antonio, TX

You don’t have to navigate unplanned pregnancy and all the emotions that come along with it alone. Our clinic provides free ultrasounds and a confidential environment to ask hard questions and sort through your thoughts.


Give us a call at (210) 651-1611, text us at (210) 638-8221, or schedule your free ultrasound today! 


Mayo Foundation for Medical Education and Research. (2022, January 20). Bleeding during pregnancy causes. Mayo Clinic. Retrieved from 

Vaginal bleeding during pregnancy: Causes & treatment. Cleveland Clinic. (2021). Retrieved from 

Alkilani, Y. G., & Apodaca-Ramos, I. (2022, April 30). Cervical Polyps. National Library of Medicine. Retrieved from 

Al Chami, A., & Saridogan, E. (2017, February). Endometrial polyps and subfertility. National Library of Medicine. Retrieved from 

Mayo Foundation for Medical Education and Research. (2022, April 19). Implantation bleeding: Common in early pregnancy? Mayo Clinic. Retrieved from  

Subchorionic hematoma: Causes, symptoms & treatment. Cleveland Clinic. (2022). Retrieved from 

Molar pregnancy. March of Dimes. (2017, October). Retrieved from