What Is Placenta Previa?

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During pregnancy, the placenta moves as the womb stretches and grows. Early in the pregnancy, it’s common for the placenta to be low in the uterus. Normally, the placenta moves toward the top of the uterus as the pregnancy goes along.

Ideally, the placenta will be sitting at the top of the uterus by the third trimester, allowing the cervix to remain open and available for labor. However, when the placenta takes up space in the bottom of the uterus, the baby may rest with their head toward the top.

Woman laying down while her doctor does an ultrasound examination on the lower abdomen.

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Risk Factors

Risk factors for placenta previa include:

  • Age: Those 35 years and older are two to three times more likely to experience placenta previa. This math works out to about one case in every 100 pregnancies. 
  • Multiple pregnancies: After the first child, people are more likely to experience placenta previa. A low-lying placenta is also a risk factor for pregnancies of multiple babies—such as twins.
  • Previous surgery: With any surgery, some scarring is left behind as part of the healing process. If you’ve ever had a cesarean section or surgery on your uterus, this can increase your risk.
  • Substance abuse: Smoking cigarettes or using drugs during pregnancy increases the risk factor for many complications, including a low-lying placenta. 
  • In vitro fertilization (IVF): Conceiving a baby through IVF does seem to increase the odds of complications with the placenta in general.

Symptoms

Typically, your doctor will identify placenta previa on an ultrasound before any symptoms appear. Ideally, your doctor will let you know what to expect with this condition, including symptoms you might experience, such as preterm labor. 

While not everyone will experience all, or any, of these symptoms, the most common symptoms of placenta previa are:

  • Bleeding: Whenever there's a problem with the placenta, vaginal bleeding is a possibility. This bleeding is typically heavier than spotting and is often painless.
  • Contractions: Some people with placenta previa will experience sharp cramping pains or even contractions.
  • Breech position: With a textbook pregnancy, the baby will be lying with their head toward the bottom of the uterus because there is more room. However, when the placenta takes up space in the bottom of the uterus, the baby will rest with their head toward the top. This position increases the chance of the baby being in a breech position during labor.

Treatment

With all pregnancies, the goal is to make it to full term. As you get closer to your third trimester, your doctor may start making recommendations to get you as close to your due date as possible. 

Some of these recommendations may include: 

  • Medication: In some cases, your doctor might recommend a medication to prevent you from going into premature labor. While these medications don't always stop preterm labor, they will at least increase the odds of making it to the 36-week mark.
  • Pelvic rest: Sometimes, giving the pelvic area a break can help reduce the symptoms and increase the odds of a full-term pregnancy. When pelvic rest is recommended, it means avoiding putting anything into the vagina, including during menstruation (tampons), intercourse, and pelvic exams.
  • Bed rest: Since bed rest can create a whole host of other problems, strict bed rest is not often recommended. However, your doctor may suggest you limit your activity level for a specific time frame. The length of time could be anywhere from a few hours each day to several days per week or longer.
  • Frequent check-ins: In some situations, the doctor may increase the frequency of your appointments. These frequent check-ins allow the doctor to monitor both mom and baby a little more closely until it's time for delivery.
  • Hospital stay: In more severe cases, your doctor will admit you to the hospital until the baby is born. A hospital stay happens when your doctor feels it is necessary to keep an eye on you and the baby around the clock.

Complications

Keep in mind that while placenta previa sounds scary, the condition itself is not dangerous for you or the baby. However, there are serious risks and potential complications from the placenta being in the wrong place. These possible complications are why your doctor will monitor you a little more closely as the due date gets nearer. 

Possible problems from placenta previa include:

  • Future risk: Once you’ve had placenta previa, you’re more likely to have it again in future pregnancies. 
  • Preterm labor: Placenta previa increases the chance of your baby being born before the due date. 
  • Hemorrhage: Placenta previa increases the risk of uncontrolled bleeding during pregnancy. Sometimes the bleeding is severe enough to result in a blood transfusion or hysterectomy.
  • Placenta accreta: Placenta accreta happens when the placenta grows more deeply in the wall of the uterus than it should. This condition can create life-threatening bleeding during labor and delivery. 

A Word From Verywell

Pregnancy is an exciting, overwhelming, and nerve-racking time for many people. If you have concerns about experiencing placenta previa—or have concerns about being diagnosed with placenta previa—it’s essential to talk to your doctor about them.

In many cases, just knowing how focused your doctor is about your case and what their plan is for monitoring you and your baby through delivery can help ease a diagnosis's anxiety. 

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