Bleeding During Pregnancy: Causes by Trimester & What to Do

Medical review: Dr. Sheila Sedicias
December 2022

Bleeding during pregnancy is a relatively common occurrence that does not always signal something serious. However, it is important that it be assessed by a doctor as soon as detected, as any serious causes should be ruled out. 

Causes for bleeding can vary depending on the mother’s trimester, which is why knowing the gestational age is important for the doctor’s assessment. 

Slight losses of dark pink, red, or brownish blood may be normal and typically result from changes that occur in the woman’s body. However, these same symptoms can also occur due to more serious conditions, like a miscarriage or an ectopic pregnancy. In the case of serious situations like these, usually, the blood loss suddenly becomes more abundant, and the blood becomes bright red. 

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What can cause blood loss during pregnancy?

The most conditions that can lead to blood loss in pregnancy are:

  • Normal spotting from cervical irritation;
  • Ectopic pregnancy;
  • Subchorionic hematoma:
  • Placental abruption;
  • Placenta previa;
  • Miscarriage;
  • Uterine infection.

Because there are many causes for bleeding during pregnancy, pinpointing the exact one may be difficult to distinguish, therefore you should notify you obstetrician promptly so that you can be assessed.

Bleeding by trimester

Additionally, the causes of the bleeding can vary according to the stage of pregnancy:

1. First trimester

Bleeding in the first trimester of pregnancy is common in the first 15 days after conception and, in this case, the bleeding is a pinkish color, lasts about two days, and causes cramps that are similar to period cramps. It is referred to as implantation bleeding. Read more about what implantation bleeding looks like and what to expect. 

This may be the first pregnancy symptom in some women so it is important to carry out a pregnancy test. 

What it can be: Even though some scant bleeding is normal during this stage of pregnancy, if the bleeding becomes intense, very bright red, or accompanied by nausea and cramps, it can indicate a miscarriage or ectopic pregnancy, both which require immediate attention.

What to do: You should be seen by your obstetrician or proceed to an emergency department immediately if bleeding is heavy and bright red. 

During the first three months of pregnancy, the mother may also present dark discharge, similar to coffee color, which appears on no particular day as it is not linked to a menstrual cycle. If this is the case, it could be subchorionic hematoma which can lead to a miscarriage. Read more about brown discharge during pregnancy.

2. Second trimester

The second trimester encompasses the fourth to sixth month of pregnancy. It starts on week 13 and finishes on week 24 of gestation.

What it can be: After the first three months of pregnancy, pregnancy bleeding is not as common. If it occurs, it can indicate placental abruption, miscarriage, placenta previa, cervicitis, or a wound in the uterus caused by contact

What to do: You are advised to notify your obstetrician or proceed to emergency department as soon as possible.

Other warning symptoms will usually occur with serious causes of blood loss. These symptoms can include abdominal pain, fever, or a decrease in fetal movement. 

3. Third trimester

Causes for blood loss during the third trimester can range from normal labor to a more serious problem.

What it can be: in some cases, the blood loss can indicate placenta previa or placental abruption. However, some women present with blood loss at the end of pregnancy due to loss of the mucous plug and the water breaking. Women who are at the onset of labor will note irregular contractions that gradually become more regular and more intense.   

What to do: You are advised to notify your obstetrician and proceed to emergency department as soon as possible.

In the last three months, it is also common for the woman to bleed after sexual intercourse, as the birth canal becomes more sensitive and bleeds easily. In this case, the woman should only go to the hospital if the bleeding lasts more than one hour.

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Written and updated by Daisy Oliveira - Registered Nurse on December of 2022. Medical review by Dr. Sheila Sedicias - Gynecologist, on August of 2020.
Medical review:
Dr. Sheila Sedicias
Physician graduated in Mastology and Gynecology by UFPE in 2008 and member no. 17459 of CRM-PE, Brazil.