The placenta supplies food and oxygen to your baby.
Sometimes the placenta attaches itself to the wall of the uterus too deeply, which can cause several problems.
While rare, these conditions can cause dangerous bleeding.
Talk with your provider if you have any bleeding from your vagina while you are pregnant.
The placenta grows in your uterus (womb) and supplies your baby with food and oxygen through the umbilical cord.
Normally, the placenta grows onto the upper part of the uterus and stays there until your baby is born. During the last stage of labor, after giving birth, the placenta separates from the wall of the uterus, and your contractions help push it into the vagina (birth canal). This is also called the afterbirth.
Sometimes the placenta attaches itself into the wall of the uterus too deeply and doesn’t go out after giving birth (delivery of the placenta). This can cause problems, including:
- Placenta accrete – The placenta attaches itself too deeply and too firmly into the uterus.
- Placenta increta – The placenta attaches itself even more deeply into the muscle wall of the uterus.
- Placenta percreta – The placenta attaches itself and grows through the uterus, sometimes extending to nearby organs, such as the bladder.
In these conditions, the placenta doesn’t completely separate from the uterus after you give birth. This can cause dangerous bleeding. These conditions happen in about 1 in 530 births each year.
What are the signs of these placental conditions?
Placental conditions may cause vaginal bleeding in the third trimester. Call your health care provider right away if you have vaginal bleeding anytime during your pregnancy. If the bleeding is severe, go to the hospital right way.
How are these placental conditions diagnosed?
These conditions usually are diagnosed using ultrasound. In some cases, your provider may use magnetic resonance imaging (MRI). MRI is a medical test that makes a detailed picture of the inside of your body. The test is painless and safe for you and your baby and it will tell if there may be problems with the delivery of the placenta.
How are these placental conditions treated?
When these conditions are found before birth, your provider may recommend a cesarean section (also called c-section) immediately followed by a hysterectomy. This can help prevent bleeding from becoming life threatening. A c-section is surgery in which your baby is born through a cut that your provider makes in your belly and uterus. A hysterectomy is when your uterus is removed by surgery. Without a uterus, you can’t get pregnant again in the future.
If you have a placental condition, the best time for you to have your baby is unknown. But your provider may recommend that you give birth at around 34 to 38 weeks of pregnancy to help prevent dangerous bleeding. The provider will also prepare for other emergency procedures that could happen, such as a blood transfusion. If you want to have future pregnancies, your provider may use special treatments before the c-section to try to control bleeding and save your uterus.
If your provider finds out that the placenta doesn’t separate after giving birth, the provider may try to remove the placenta in surgery to stop the bleeding.
There are some methods such as special sutures to tie off the major bleeding blood vessels or a balloon (Bakri) that can be placed inside the uterus to block the bleeding. If these methods don’t stop the bleeding, a hysterectomy is necessary.
What causes these placental conditions?
We don’t know what causes these kinds of placental conditions. These conditions also happen where you have a scar from a surgery, like having a previous c-section or after removing a tumor that grows in the wall of the uterus (fibroid).
If you’ve had a c-section, you’re more likely to have these kinds of conditions than if you had a vaginal birth. And the more c-sections you’ve had, the more likely you are to have these placental problems.
Things that may make you more likely to have these kinds of placental conditions include:
- Smoking cigarettes
- Previous c-section
- Previous surgery in your uterus
- Previous dilatation and curettage
- Being 35 or older
- Having been pregnant before
- Past radiation to your pelvis, possibly during cancer treatment
- Having placenta previa
- Having endometriosis
Becoming pregnant by in vitro fertilization (IVF)
How can you reduce your risk for placental conditions?
One way to reduce your chances for having these kinds of placental conditions in future pregnancies is to have your babies by vaginal birth instead of c-section, if possible. Have a c-section only if there are health problems with you or your baby that make it medically necessary. For some moms and babies, health problems make c-section safer than vaginal birth.
If your pregnancy is healthy, it’s best to stay pregnant until labor begins on its own. Don’t schedule a c-section for non-medical reasons, like wanting to have your baby on a certain day or because you’re uncomfortable and want to have your baby earlier than your due date.
Even if you’ve already had a c-section, you may be able to have your next baby by vaginal birth. This is called vaginal birth after cesarean (also called VBAC). You may be able to have a VBAC depending on what kind of incision (cut) you had in your c-section and your overall pregnancy health. Talk to your provider if you think VBAC may be right for you.
What are some other placental problems?
In some cases, the placenta doesn’t develop correctly or work as well as it should. It may be too thin, too thick or have an extra lobe. The umbilical cord may not be attached correctly. The cord may have two vessels instead of three. Problems like infections, blood clots and infarcts (an area of dead tissue, like a scar) can happen during pregnancy and damage the placenta. Some of these problems may be diagnosed during your routine ultrasounds and followed closely to make sure they don’t cause other problems.
Placental problems like these can lead to health risks for you and your baby. Some of these risks include:
- You may have a miscarriage.
- Your baby doesn’t grow as well as they should during pregnancy.
- You may have increased bleeding at birth.
- You may have a premature birth. This is birth that happens too soon, before 37 weeks of pregnancy.
- Your baby may have birth defects.
Your provider checks the placenta after birth to make sure it is normal and that it was delivered completely. Sometimes the placenta is sent for testing in a lab, especially if the baby has certain health problems, like poor growth. The results of this test is called pathology and you can ask about it in your postpartum visit.
Last updated: January 2022