11 Factors That Can Cause Bleeding During Pregnancy

Causes of bleeding during pregnancy include implantation bleeding, ectopic pregnancy, and miscarriage.

Spotting or vaginal bleeding during pregnancy can be quite scary. But it’s not as uncommon as you might think. In fact, bleeding occurs during the first trimester in around 15 to 25% pregnancies.1 So is bleeding during pregnancy a given or should you be worried? The answer is that it depends.

1 in 4 women sees some bleeding in the first 12 weeks of pregnancy. About 50% of these may end in a miscarriage.2 So, it’s a good idea to see your OB/GYN if you experience bleeding at any point during your pregnancy to rule out serious health concerns.


In some cases, bleeding during pregnancy can be quite harmless, while in others it may be caused by a serious condition that may pose a risk to the baby’s and your well-being. Typically, bleeding that occurs during the second or third trimester is more likely to be caused by a complication.3 Let’s take a closer at various factors that may cause bleeding while you’re expecting. 4

1. Implantation Bleeding

You might have spotting or light bleeding around 1–2 weeks after fertilization, when the fetus implants itself in the wall of your uterus. This is known as implantation bleeding and usually occurs around the time your first period would have been due after conception.


2. Cervical Bleeding

When you become pregnant, blood supply to the womb and cervix increases and more and more blood vessels develop in the area. Because of this, your cervix is more prone to bleeding during pregnancy and becomes a “friable” cervix which can be irritated or injured easily. You may, for instance, notice light bleeding or spotting after a pelvic exam, pap test, or sexual intercourse. Refrain from sexual intercourse before a physical examination, so you can prevent further irritation to the cervix.5 6

3. Infections

Certain infections that cause vaginal bleeding may also be responsible for bleeding during pregnancy. This may include sexually transmitted infections such as chlamydia or gonorrhea or infections such as thrush or bacterial vaginosis. Other signs of an infection may include pain or a burning sensation after urination, abnormal vaginal discharge, and pain during sex.7 8 9 10


Remember, some of these infections can be passed on to the baby from the mother or cause complications during the pregnancy. So it is important to see a doctor if you have these signs so they can be correctly diagnosed and treated.

4. Ectopic Pregnancy

In some cases, a fertilized egg doesn’t implant in the uterus. Instead, it implants elsewhere, often in your fallopian tube. This is known as an ectopic pregnancy. During an ectopic pregnancy, the fallopian tube can rupture and cause internal bleeding. Blood loss may then lead to weakness, pain, fainting, and shock. It can even be fatal in some cases.


Vaginal bleeding can sometimes be the only symptom experienced during an ectopic pregnancy although you may feel abdominal, shoulder, or pelvic pain. Do see a doctor immediately if you experience these symptoms. And remember, it’s possible for these symptoms to occur even before you realize or confirm you are pregnant. Unfortunately, it’s not possible to save the pregnancy in this case.

5. Molar Pregnancy

Heavy bleeding with or without blood clots, stomach pain, and backache may indicate a miscarriage or ectopic pregnancy. See a doctor immediately.


In some cases, a baby doesn’t develop properly in the womb and you may see a growth of a clump of abnormal cells instead of a fetus. In many cases, this may not cause any symptoms and may only be detected during an ultrasound. However, some women may experience vaginal bleeding with or without tiny lumps similar to grapes. Other signs of a molar pregnancy may include severe morning sickness or an abnormally swollen tummy. Your doctor will usually remove the abnormal cell growth if you have this condition.11 12

6. Miscarriage

Cramping and bleeding can be signs of loss of a pregnancy or miscarriage. Vaginal bleeding later in the pregnancy can also point toward a miscarriage. However, miscarriages are rarer after the 3rd month. Also, do keep in mind that around 50% of women who miscarry do not experience bleeding, so it’s not the only indication.13


7. Cervical Ectropion

Cervical ectropion is another common cause of bleeding, especially in the later months of pregnancy. This happens because of changes to the cells in the cervix during pregnancy. Glandular or soft cells that exist within the cervical canal may spread to the outside surface of the cervix. These are more delicate than epithelial cells found in this area and may bleed faster. Bleeding is particularly likely after sex. However, this does not cause any harm.14 15 Your doctor will confirm the condition after a thorough examination.

8. Placental Abruption

Placental abruption is a condition where the placenta gets detached from the uterus wall and can occur before birth or during the delivery. Apart from vaginal bleeding, you may experience back pain and abdominal pain. Placental abruption can cause severe complications if it’s not detected early enough as it may result in the baby not getting sufficient oxygen or the expectant mother losing excessive amounts of blood. If placental abruption occurs close to the due date, the baby may be delivered early.


9. Placenta Previa

When your placenta lies low in your womb, it may completely or partly block your baby’s way to the cervix. This is known as placenta previa. And it can cause vaginal bleeding usually without pain. Sometimes, placenta previa resolves on its own between the 32nd and the 35th week of pregnancy as the placenta slowly moves up during the pregnancy. But if the placenta is still low when you are due to give birth, you might need to have a cesarean delivery.

10. Placenta Accrete

In women with placenta accrete, the placenta or a part of it cannot be separated from the uterine wall. This condition causes bleeding during the last trimester and excessive, even life-threatening, loss of blood during delivery. Most cases of placenta accrete are detected during routine ultrasound exams. If you have placenta accrete, your doctor may need to perform a hysterectomy after delivery to prevent excessive blood loss. You may also need to go to a hospital that specializes in dealing with this complication for the birth.

11. Preterm Labor

Vaginal bleeding late in your pregnancy can be a sign that your body is preparing for labor to begin. This happens when blood mixed with the mucus plug that sealed your cervix during the pregnancy comes off before labor. If this happens before your due date, it could point toward early labor. Your doctor will do a pelvic exam to check if your cervix has changed to confirm if you are going into labor. You may also see regular or frequent contractions, back pain, and pelvic pressure.16

A host of normal physiological changes can cause bleeding during pregnancy just as much as certain serious health issues. So don’t panic just yet. The important thing is to be alert to these changes and report them to your doctor immediately. With some care and prompt medical attention, things should get back to normal.