Women who give birth vaginally typically deliver the placenta minutes after baby arrives. Some expectant mothers, however, develop a condition in which the placenta fastens itself too deeply into the wall of the uterus—the deeper inside the uterus the blood vessels of the placenta penetrate, the more severe the condition.
Placenta accreta—which occurs when the placenta affixes to the uterus but doesn’t pierce the muscle—accounts for 75 percent of abnormal placental attachments. Far less common is when the placenta penetrates the uterine muscle (placenta increta) or when the placenta punctures the uterus so deeply it attaches to the bladder or another organ (placenta percreta). Placenta accreta is present in three out of every 1,000 deliveries, according to the Society for Maternal-Fetal Medicine.
Placenta accreta poses dangers to mothers-to-be and developing infants alike. It can cause severe, potentially life-threatening bleeding and uterine damage during delivery. Placenta accreta may also trigger preterm birth, which can result in underdevelopment-related health problems for babies.
What causes placenta accreta remains unclear, but the condition could be related to uterine abnormalities, such as those resulting from surgery. As C-section rates climb, so do the rates of placenta accreta.
During pregnancy, placenta accreta rarely provides clues to its presence, so knowing the risk factors that affect you and sharing them with your obstetrician are crucial. If you’ve had a uterine procedure in the past, you have an above-average risk for placenta accreta. Have you had a cesarean section to deliver a previous child? If so, you’re more likely to develop abnormal placental attachment. Placenta previa—placenta that obstructs or covers the cervix—is a risk factor for placenta accreta, as well.
If your physician knows you are at high risk for placenta accreta, he or she can monitor you for rare symptoms, such as third-trimester bleeding, and search for the condition with imaging, typically via ultrasound. Diagnosing placenta accreta prior to delivery is infinitely preferable to discovering it on the big day, when it will be more difficult for the delivery team to manage.
With advance knowledge that placenta accreta is present, you and your obstetrician can plan your delivery accordingly and ensure all of the specialists you need will be on hand. He or she may recommend delivering early via C-section and a hysterectomy to reduce the risk of severe bleeding. If you want to get pregnant again, speak with your physician about alternatives to hysterectomy.
With a plan in place, you’ll have greater peace of mind knowing you have an entire medical team in your corner ready to help you and your baby overcome the challenge of placenta accreta.