Medically reviewed by Drugs.com. Last updated on May 30, 2020.
The placenta is a structure that develops inside your uterus during pregnancy, providing oxygen and nutrition to and removing wastes from your baby. The placenta connects to your baby through the umbilical cord. In most pregnancies, the placenta attaches at the top or side of the uterus.
Placenta previa (pluh-SEN-tuh PREH-vee-uh) occurs when a baby's placenta partially or totally covers the mother's cervix — the outlet for the uterus. Placenta previa can cause severe bleeding during pregnancy and delivery.
If you have placenta previa, you might bleed throughout your pregnancy and during your delivery. Your health care provider will recommend avoiding activities that might cause contractions, including having sex, douching, using tampons, or engaging in activities that can increase your risk of bleeding, such as running, squatting, and jumping.
You'll need a C-section to deliver your baby if the placenta previa doesn't resolve.
The placenta is a structure that develops in the uterus during pregnancy. In most pregnancies, the placenta is located at the top or side of the uterus. In placenta previa, the placenta is located low in the uterus. The placenta might partially or completely cover the cervix, as shown here. Placenta previa can cause severe bleeding in the mother before or during delivery. A C-section delivery might be required.
Bright red vaginal bleeding without pain during the second half of pregnancy is the main sign of placenta previa. Some women also have contractions.
In many women diagnosed with placenta previa early in their pregnancies, the placenta previa resolves. As the uterus grows, it might increase the distance between the cervix and the placenta. The more the placenta covers the cervix and the later in the pregnancy that it remains over the cervix, the less likely it is to resolve.
When to see a doctor
If you have vaginal bleeding during your second or third trimester, call your doctor right away. If the bleeding is severe, seek emergency medical care.
The exact cause of placenta previa is unknown.
Placenta previa is more common among women who:
- Have had a baby
- Have scars on the uterus, such as from previous surgery, including cesarean deliveries, uterine fibroid removal, and dilation and curettage
- Had placenta previa with a previous pregnancy
- Are carrying more than one fetus
- Are age 35 or older
- Are of a race other than white
- Use cocaine
If you have placenta previa, your health care provider will monitor you and your baby to reduce the risk of these serious complications:
- Bleeding. Severe, possibly life-threatening vaginal bleeding (hemorrhage) can occur during labor, delivery or in the first few hours after delivery.
- Preterm birth. Severe bleeding may prompt an emergency C-section before your baby is full term.
Placenta previa is diagnosed through ultrasound, either during a routine prenatal appointment or after an episode of vaginal bleeding. Most cases of placenta previa are diagnosed during a second trimester ultrasound exam.
Diagnosis might require a combination of abdominal ultrasound and transvaginal ultrasound, which is done with a wandlike device placed inside your vagina. Your health care provider will take care with the position of the transducer in your vagina so as not to disrupt the placenta or cause bleeding.
If your health care provider suspects placenta previa, he or she will avoid routine vaginal exams to reduce the risk of heavy bleeding. You might need additional ultrasounds to check the location of your placenta during your pregnancy to see if placenta previa resolves.
There is no medical or surgical treatment to cure placenta previa, but there are several options to manage the bleeding caused by placenta previa.
Management of the bleeding depends on various factors, including:
- The amount of bleeding
- Whether the bleeding has stopped
- How far along your pregnancy is
- Your health
- Your baby's health
- The position of the placenta and the baby
If placenta previa doesn't resolve during your pregnancy, the goal of treatment is to help you get as close to your due date as possible. Almost all women with unresolved placenta previa require a cesarean delivery.
For little or no bleeding
Your health care provider might recommend rest, which means avoiding activities that can trigger bleeding, such as sex and exercise.
Be prepared to seek emergency medical care if you begin to bleed. You'll need to be able to get to the hospital quickly if bleeding resumes or gets heavier.
If the placenta is low lying but doesn't cover the cervix, you might be able to have a vaginal delivery. Your health care provider will discuss this option with you.
For heavy bleeding
Heavy bleeding requires immediate medical attention at your nearest emergency health facility. Severe bleeding might require a blood transfusion.
Your health care provider will likely plan a C-section as soon as the baby can be delivered safely, ideally after 36 weeks of pregnancy. However, you might need to have an earlier delivery if heavy bleeding persists or if you have multiple bleeding episodes.
If your delivery is planned before 37 weeks, your doctor will offer you corticosteroids to help your baby's lungs develop.
For bleeding that won't stop
If your bleeding can't be controlled or your baby is in distress, you'll likely need an emergency C-section — even if the baby is premature.
Coping and support
If you're diagnosed with placenta previa, you're sure to worry about how your condition will affect you, your baby and your family. Some of these strategies might help you cope:
- Learn about placenta previa. Having information about your condition can help ease your fears. Talk to your health care provider, research on your own and connect with other women who've had placenta previa.
- Prepare for a C-section. Placenta previa might prevent you from delivering your baby vaginally. Remind yourself that you and your baby's health are more important than the method of delivery.
- Make the best of rest. Although you won't be confined to bed, you will have to take it easy. Fill your days by planning for your baby's arrival. Read about newborn care or purchase newborn necessities, either online or by phone. Or use the time to catch up on thank-you notes or other nontaxing tasks.
- Take care of yourself. Surround yourself with things that comfort you, such as good books or music you love. Give your partner, friends and loved ones suggestions for ways to help, such as visiting or making one of your favorite foods.
Preparing for an appointment
If you've been pregnant for more than 12 weeks and you develop vaginal bleeding, call your pregnancy health care provider. He or she may recommend immediate medical care, depending on your symptoms, your medical history and how far along you are in the pregnancy.
What you can do
Before your appointment, you may want to:
- Ask about pre-appointment restrictions. In most cases, you'll be seen quickly if you have a diagnosis of placenta previa. However, if your appointment will be delayed, ask whether you should restrict your activity in the meantime.
- Arrange to bring a family member or friend. Someone who's with you can help you gather and remember information.
- Write down your questions. Having a list of questions can help you make the most of your time with your health care provider.
Basic questions about placenta previa to ask your health care provider include:
- If I have placenta previa, is there a chance it could resolve on its own?
- How will my bleeding be managed?
- What follow-up care will I need during the rest of my pregnancy?
- What activity restrictions do I need? For how long?
- What signs or symptoms should prompt me to call you?
- What signs or symptoms should cause me to go to the hospital?
- Will I be able to deliver vaginally?
- Does this condition increase my risk of complications during future pregnancies?
Don't hesitate to ask other questions.
What to expect from your doctor
Your health care provider is likely to ask you a number of questions, including:
- When did you notice vaginal bleeding?
- Did you bleed only once, or has the bleeding come and gone?
- How heavy is the bleeding?
- Is the bleeding accompanied by pain or contractions?
- Have you had previous pregnancies I'm not aware of?
- Have you had uterine surgeries, including C-section, fibroid removal, or dilation and curettage after a miscarriage or abortion?
- Do you or did you smoke? How much?
- How far do you live from the hospital?
- How long would it take to get to the hospital in an emergency, including time to arrange child care and transportation?
- Do you have someone who could care for you if you need bed rest?