Placenta previa is a major complication that some women encounter during their pregnancy. In this article, we will review everything you need to know about the placenta previa.

First of all, let’s talk about the placenta.
The placenta is a new organ that develops during pregnancy. It is essential for your baby survival. The placenta serves many functions to support the baby’s healthy growth:

  • It delivers oxygen, glucose, and other nutrients to the baby.
  • The placenta filters out any substances that could be harmful to your baby.
  • It removes carbon dioxide and waste products from your baby’s blood.
  • The placenta also produces hormones such as estrogen, progesterone, and lactogen. These hormones are crucial in the maintenance of a healthy pregnancy and preparation for delivery and breastfeeding.
  • The placenta is responsible for transferring maternal antibodies that provide immune protection to the fetus and newborn baby against infection.

Due to its importance, any problems affecting the placenta can be dangerous to you and your baby. Placenta previa is one of the problems that can affect the placenta during pregnancy.

What is placenta previa?

The placenta is attached to the uterus wall and connects to the baby by the umbilical cord. In early pregnancy, the placenta usually appears low. As the pregnancy continues, the uterus grows, and the placenta moves to the top of the uterus. If the placenta stays very low during the last months of the pregnancy and covers the uterus opening (cervix), this condition is called placenta previa.
There are three types of placenta previa, depending on how much of the placenta covers the cervix:

  • Marginal placenta previa also called a low lying placenta. The placenta is next to the cervix’s edge but does not cover the opening.
  • Partial placenta previa. The placenta covers part of the cervix.
  • Complete or total placenta previa. The placenta covers the cervix completely.


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Placenta previa affects about 1 in 200 pregnant women in the third trimester of pregnancy. (1)

What are the risk factors of placenta previa?

The causes of placenta previa are still unclear, but many conditions increase the risk of placenta previa. Placenta previa risk factors include :

  • Prior diagnosis of placenta previa
  • Being older (2)
  • Previous delivery by cesarean section (3)
  • Have had a baby
  • Smoking
  • Being pregnant with more than one baby
  • Prior miscarriage
  • Having an abnormality of the uterus such as fibroids
  • Have scars on the uterus from the previous procedure

What are the symptoms of placenta previa?

Not all women with placenta previa experience symptoms. The most common symptom is bright and red vaginal bleeding during the second half of pregnancy.
During that time of the pregnancy, the cervix begins to thin out. It disrupts the blood vessels in the area of the placenta that covers the cervix. This is why women with placenta previa are likely to bleed during the third trimester. The bleeding is often painless, but uterine cramping and abdominal pain may occur in some women. When the cervix starts to open up for the delivery, more vessels are damaged, making the bleeding more severe.
The risk of bleeding is higher if a lot of the placenta covers the cervix.

If you have vaginal bleeding anytime during your pregnancy, go to the emergency room.

How soon placenta previa can be detected, and how is it diagnosed?

Placenta previa is diagnosed through a transabdominal or transvaginal ultrasound scan during a routine prenatal visit in the second trimester (around 20th week). Some women will get a diagnosis of placenta previa when they begin experiencing painless bleeding. For the majority of women who have been diagnosed with placenta previa early in the pregnancy, it usually resolves on its own. But, the more the placenta covers the cervix, the less likely it is to improve. A placenta previa is usually not confirmed until the third trimester.

What are placenta previa complications?

When placenta previa does not resolve, the placenta blocks the cervix’s opening, allowing the baby to pass through the birth canal during delivery. This requires an emergency delivery by c-section. Placenta previa in the third trimester can lead to life-threatening complications such as:

  •  Blood loss for the mother and the baby
  • Shock of the mother if the bleeding is excessive
  • Reduction of fetal growth
  • Health risks to the baby due to preterm birth
  • Birth injury in the baby
  • Placenta accreta. Some women who have placenta previa are more likely to have the placenta that grows too deeply into the uterus and doesn’t come away easily after the delivery. This pregnancy complication is called placenta accreta and often leads to excessive bleeding if the placenta fails to separate. It may require a hysterectomy to control the bleeding.

What is the treatment for placenta previa

Placenta previa is not preventable. As we said before, most of the cases of placenta previa will resolve on their own. When it persists until the third trimester, your doctor may recommend measures to ensure you have a safe pregnancy and delivery, especially if you experience bleeding.
The severity of the bleeding is the first factor that will condition your healthcare provider’s treatment choice.

  • When you don’t experience any bleeding or have minimal bleeding, doctors will recommend bed rest at home. You will also have to avoid exercise, including sex.
  • In case of heavy bleeding, you may have to remain at a hospital until your delivery to monitor you and your baby continuously. You may also need to take medicine to prevent premature labor if you are under 36 weeks.
  • If the bleeding is uncontrollable, an emergency cesarean delivery will have to be performed. You may receive steroid shots for maturing your baby’s lungs and brain more quickly before a C-section.

If the mother has lost a lot of blood, it may require blood transfusions.




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About the Author

Hermione M.

My name is Hermione. I am the founder of WomenH and I write about women's health, wellness, mental health, and personal growth. I created this platform to inspire women to take care of themselves mentally, physically, and emotionally to become their best selves. Thank you for stopping by.

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