Placenta Previa: Symptoms, Causes, and How to Treat It

You’re probably already familiar with the placenta—the organ that keeps your baby nourished in the womb.

Unfortunately, the placenta can also cause trouble when it settles in the wrong place in your belly. Here’s everything you need to know about placenta previa, what it means for you and your baby, and what your treatment options are.

The placenta is a pancake-shaped organ that typically attaches to the upper uterus. It removes waste and supplies nutrients and oxygen to your little one via the umbilical cord.

Placenta previa is when your placenta partially or entirely covers your cervix—the opening to the birth canal. This unfortunate positioning can lead to bleeding during pregnancy and problems during delivery, and almost guarantees you’ll need a cesarean section (C-section). 1

Types of placenta previa

This condition is classified differently depending on how covered your cervix is, with three distinctions: 1

• Complete previa (the internal os, your cervical opening, is fully covered)
• Partial previa (your cervical opening is only partly covered)
• Marginal placenta previa (the placental edge is within 2 cm of the internal os)

How common is placenta previa?

The placenta encroaches on the cervix in roughly 1 in 200 pregnancies. The good news is that an early low-lying placenta previa diagnosis has a high chance (around 90%) of resolving on its own as your uterus grows. In these cases, the placenta simply migrates away from your cervix. 2

Risk factors

Any woman can develop placenta previa, but certain factors increase your risk of developing it, such as: 3 4

• Being over 35
• Having had more than one child
• Carrying multiples
• Having had previous C-sections
• Using assisted reproductive technologies (ART) like in vitro fertilization (IVF)

Additionally, smoking or using certain drugs (such as cocaine) during your pregnancy can increase your risk of developing placenta previa. (Needless to say, engaging in that sort of activity is a bad idea for lots of other reasons, too, regardless of whether you’re pregnant or not.)

If you have placenta previa, your doctor will usually spot it during one of your routine second-trimester ultrasounds, before you experience noticeable symptoms.

Some women, however, report the following warning signs:

• Painless vaginal bleeding: This is the most common symptom. It shows up as bright red blood in the second half of your pregnancy (going into the third trimester). Triggers include cervical changes like thinning and dilation. 5
• Uterine contractions: Look for preterm contractions or cramping along with bleeding. 6

When you’re pregnant, you should report any vaginal bleeding to your doctor immediately to rule out placenta previa or other potential issues.

How do doctors confirm diagnoses of placenta previa?

If your doctor suspects you have placenta previa, you can expect to receive an ultrasound to locate your wayward organ’s position. This involves placing a transducer on your belly or inserting the device vaginally to determine if the placenta is covering the cervix and to what extent.

As mentioned, ultrasounds are routine and most women receive quite a few over the course of their pregnancies. By the time a diagnosis of placenta previa becomes a realistic possibility, you’ll be an old hand at this, and the check to confirm the condition won’t be anything you aren’t used to.

There’s no way to “cure” placenta previa. The goal of treatment is to manage the condition and minimize the risks to you and your baby.

Your doctor will tailor a plan to your circumstances, considering factors like how heavy your bleeding is (if you’re bleeding at all), how far along you are, and your overall health.

Here’s what your management plan might include: 3

• Pelvic rest: You’ll need to avoid sexual activity, introducing any foreign objects into your vagina, and vaginal exams to prevent disrupting the placenta.
• Activity restrictions: Your doctor may recommend limiting strenuous activities, exercise, and prolonged standing. They may also suggest you get plenty of bed rest.
• Hospitalization: Expect a hospital stay if you’re bleeding heavily. Your doctors will want to keep you under close observation for a while to make sure your condition doesn’t worsen.
• Medications: Your doctor might prescribe medications to prevent preterm labor or inject you with a corticosteroid to mature your baby’s lungs in case early delivery becomes necessary. You may also receive an Rh immunoglobulin (Rhlg) injection (e.g., a RhoGAM shot), which can prevent other disorders if you have Rh-negative blood. 7
• Monitoring: You’ll have regular ultrasounds and fetal heart rate checks.

Delivery options with placenta previa

The placenta’s location will determine the safest delivery method for you and your baby. 8

• Cesarean section (C-section): If the placenta completely or partially blocks your cervix, you’ll need a C-section to avoid life-threatening bleeding during labor and delivery. Your doctor will try to hold out for a minimum of 36 weeks before a scheduled C-section.
• Vaginal delivery: In rare cases where the placenta is low-lying but not covering your cervix fully, you could still deliver vaginally. Lean on your doctor to weigh the health factors and see if this is the right path to take.

Potential complications of placenta previa

While you can take heart in knowing that most women with placenta previa deliver healthy babies, you should still be aware of the potential complications this condition can cause: 9

• Preterm birth: Placenta previa ups your risk of premature delivery. Consequently, it puts your baby at higher risk of issues that disproportionately affect “preemies,” such as cerebral palsy.
• Breech position: With the placenta blocking the lower part of the uterus, the limited space may make your baby hesitant to shift to the normal head-first position. If your baby is in the “breech” (feet first) position at term, you’ll need a C-section.
• Hemorrhage: You’ll be looking at blood transfusions or, in rare cases, a hysterectomy (removal of the uterus) if bleeding becomes severe during pregnancy, labor, or post-delivery.
• Placenta accreta: This refers to the placenta attaching too deeply into the uterine wall, making post-delivery separation difficult and increasing your risk of hemorrhage.
• Placental abruption: With this condition, you’ll experience either a partial or complete separation of the placenta from the uterine wall before you deliver. This risks heavy bleeding and hinders your baby’s oxygen supply.
• Vasa previa: This rare condition sees fetal blood vessels cross the cervical opening. If the membranes rupture, it can cause a fetal hemorrhage. 10

Lastly, having placenta previa can endanger your future pregnancies. Statistically, if you’ve had this condition once, you’re at a higher risk of having it again later.

Placenta previa isn’t a condition you can predict, and if it develops, it wasn’t your fault. Fortunately, if you take your health seriously, there’s a lot you can do to boost your odds of having a positive outcome.

Listen to your doctor when it comes to rest and physical activity, and be open with them about how you’re doing. When the time comes, trust in the support of everyone around you, knowing that you’ve done all you could for yourself and your baby.