Medically reviewed by Drugs.com. Last updated on Sep 3, 2023.
What is placenta previa?
Placenta previa is a condition that causes your placenta to grow near or completely over the opening to your cervix. It can also be called a low-lying placenta. The placenta supplies the baby with nutrients and oxygen during your pregnancy. It also takes away waste produced by your baby. Normally the placenta grows either on the side or top of your uterus (womb). If your placenta grows too near your cervix, it could grow completely over it and block the opening to your vagina. This may cause vaginal bleeding that is harmful to you and your baby.
What increases my risk for placenta previa?
The cause of placenta previa is still not clear. Any of the following may increase your risk:
- Age 35 or older
- Cigarette or cocaine use
- Being pregnant with twins, triplets or more
- Past C-section that caused scarring
- Past placenta previa
- Uterine scarring from past surgery or abortion
- Fertility treatments to help you get pregnant
What are the signs and symptoms of placenta previa?
- Bleeding a small amount (spotting) or a large amount, usually late in the second trimester
How is placenta previa diagnosed?
Placenta previa is often found during a normal pregnancy visit with your healthcare provider. The later in your pregnancy it is found, the higher the risk that it will not go away. Your provider will ask about your health and any past pregnancies. Tell him or her if you have had past uterine surgeries or procedures. Your provider may check your cervix by gently putting a speculum into your vagina. A speculum is a tool that opens your vagina to help your healthcare provider see your cervix. You may also need any of the following:
- An abdominal ultrasound is used to see if you have placenta previa. It is also used to check your baby for any problems during your pregnancy. A small device is moved around your abdomen and takes pictures of your uterus, placenta, and baby.
- A transvaginal ultrasound helps your provider judge how much of the cervix is covered by your placenta. A tube is passed through your vagina to get a clearer view of both your unborn baby and your placenta.
- A Doppler ultrasound may be done to check if your placenta has grown into the wall of your uterus.
- MRI pictures show how and where your placenta is growing. You may be given contrast liquid to help your placenta show up better in pictures. Tell your provider if you have ever had an allergic reaction to contrast liquid. Do not enter the MRI room with anything metal. Metal can cause serious injury. Tell the provider if you have any metal in or on your body.
How is placenta previa treated?
Placenta previa may go away later in your pregnancy, and you may not need treatment. Your placenta may move when your uterus changes shape as you get closer to delivery. If you need treatment, it may depend on how far along you are in your pregnancy. Your treatment also depends on how much of your cervix is covered by your placenta. You may need any of the following:
- You may need to be on bedrest until your baby is ready to be born. You may be able to rest at home, or you may need to stay in the hospital. If you are in the hospital, your healthcare provider may keep you on a monitor. A monitor is used to watch your vital signs (heart rate, breathing, and blood pressure). You may also need to wear a fetal monitor. Ask your provider which activities you may do while you are on bedrest.
- You may need a blood transfusion if you lose a large amount of blood. During a blood transfusion, you will get donated blood through an IV. You may need a transfusion while you are still pregnant or after your baby is born.
- Medicines may be needed. Medicine may be given to help your baby's lungs mature if your due date is close. Medicine may be given to stop contractions if your due date is not close.
- An amniocentesis (amnio) may be done to check your baby's lungs if you have a C-section date planned. An amnio may be done between weeks 36 and 37 of your pregnancy if you are not bleeding. Ask your provider for more information about amniocentesis.
- Your baby may need to be delivered early. If your due date is close, you may be able to give birth vaginally. If your placenta covers most or all of your cervix, a C-section will be done. A C-section may also be done if you have heavy bleeding, or you or your baby is in danger.
The following list of medications are in some way related to or used in the treatment of this condition.
How can I manage placenta previa?
- You will need to have a safety plan until your baby is born. Make sure you live or are staying a short distance from the hospital. You will also need to make sure someone is ready to take you to the hospital if needed.
- Do not douche or have sex. These may cause bleeding.
Call your local emergency number (911 in the US) if:
- You have chest pain when you take a deep breath or cough.
- You cough up blood.
- You suddenly feel lightheaded and short of breath.
- You have any amount of bleeding from your vagina.
- You are having severe abdominal pain or contractions.
When should I seek immediate care?
- You feel faint or too weak to stand up.
When should I call my doctor or obstetrician?
- You feel abdominal cramps, pressure, or tightening.
- Your heart is beating faster than normal for you.
- You have questions or concerns about your condition or care.
Care AgreementYou have the right to help plan your care. Learn about your health condition and how it may be treated. Discuss treatment options with your healthcare providers to decide what care you want to receive. You always have the right to refuse treatment. The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.
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