Placenta accreta affects roughly 1 in 313 deliveries in the United States, making it far more common today than it was a generation ago. In the 1980s, the rate was closer to 1 in 2,500 deliveries. That eightfold increase reflects two parallel trends: rising cesarean delivery rates and better diagnostic tools that catch cases that might have been missed before.
How Rates Have Changed Over Time
Between 2016 and 2022, the rate of placenta accreta spectrum disorders climbed by about 2.9% per year in the U.S. A large national analysis of over 27 million pregnancy-related hospitalizations identified 36,310 cases, working out to 133 per 100,000 hospitalizations. That steady climb shows no sign of leveling off.
The increase has not affected all groups equally. Rates rose most notably among Black and White individuals during this period. Meanwhile, placenta previa, a condition where the placenta covers the cervix and often occurs alongside accreta, stayed essentially flat over the same years. This suggests the rise in accreta is not simply a byproduct of more previa diagnoses.
What Placenta Accreta Actually Is
In a normal pregnancy, the placenta attaches to the uterine wall and separates cleanly after birth. In placenta accreta, the placenta grows too deeply into the uterine wall and doesn’t detach on its own. This can cause severe, life-threatening bleeding during or after delivery.
The condition exists on a spectrum with three levels of severity. In the mildest and most common form (accreta), the placenta attaches too firmly but doesn’t penetrate the uterine muscle. In increta, it invades into the muscle itself. In percreta, the most severe form, it grows through the uterine wall and sometimes into nearby organs like the bladder. Among women who undergo cesarean delivery and are diagnosed with a form of this condition, about 77% have accreta, 13% have percreta, and 10% have increta.
Why Cesarean History Is the Biggest Factor
Prior cesarean delivery is the single strongest driver of placenta accreta risk, and it’s the main reason rates have surged. Each cesarean creates a scar on the uterus, and when a future placenta implants over that scar tissue, it can grow abnormally deep. The risk compounds with each additional cesarean.
When placenta previa occurs alongside a history of cesarean delivery, the combination is especially dangerous. Women with both conditions have more than four times the odds of developing accreta compared to those with previa alone. They also face dramatically higher odds of needing a hysterectomy during delivery (more than 20 times higher) and of urinary tract injuries during surgery. By the fifth cesarean, the risk of accreta with previa can exceed 67%.
IVF Pregnancies Carry Higher Risk
Pregnancies conceived through IVF carry a notably elevated risk of placenta accreta. The odds ratio ranges from 3 to 14 compared to spontaneous conception, meaning IVF pregnancies are roughly 3 to 14 times more likely to involve some degree of abnormal placental attachment. Frozen embryo transfers using hormone replacement cycles appear to carry a higher risk than fresh embryo transfers, possibly because the hormonal preparation alters how the uterine lining develops before the embryo implants.
How It’s Detected Before Delivery
Most cases are now caught before birth through prenatal ultrasound, which picks up placenta accreta with 85 to 90% sensitivity and 78 to 82% specificity. That means ultrasound correctly identifies the condition in the vast majority of affected pregnancies, though it occasionally flags a normal placenta as abnormal.
Radiologists look for specific warning signs on imaging. One is abnormal blood vessel patterns between the placenta and bladder wall. Another, called the “separation sign,” checks whether the placenta and uterine wall show a clear boundary between them. When that boundary is absent, it suggests the placenta has invaded the muscle. A visible pulsating blood vessel on the back wall of the bladder is another red flag with very high detection accuracy. MRI can supplement ultrasound in ambiguous cases, particularly for evaluating how deeply the placenta has invaded.
What Delivery Looks Like
When accreta is diagnosed before birth, the standard approach is a planned cesarean delivery, typically scheduled between 34 and 37 weeks of gestation. Delivering early reduces the chance of going into labor spontaneously, which could trigger uncontrolled bleeding. Some guidelines favor the 34 to 35 week window, while others extend to 36 or 37 weeks depending on severity and stability.
In many cases, a hysterectomy is performed at the same time as the cesarean because attempting to remove the placenta from the uterine wall can cause massive hemorrhage. However, conservative management, where surgeons leave part of the placenta in place and allow the body to reabsorb it over time, is an option for some women. Studies comparing the two approaches have found that conservative management results in less blood loss, fewer transfusions, and less injury to surrounding organs. Average blood loss with conservative surgical management is around 1,000 mL, which is significant but manageable with transfusion support when needed. Some women managed conservatively do still end up needing a hysterectomy later if bleeding or infection develops.
Why Early Detection Matters So Much
The gap between a planned and unplanned accreta delivery is enormous in terms of outcomes. When the diagnosis is known ahead of time, the birth can happen at a specialized center with a surgical team that includes maternal-fetal medicine specialists, experienced anesthesiologists, a blood bank prepared with units on standby, and urologists or other surgeons available if the placenta has invaded neighboring organs. When accreta is discovered unexpectedly during a routine cesarean, the risk of life-threatening complications rises sharply because the hospital may not have those resources immediately available.
This is one reason the rising rate matters so much. As more pregnancies are affected, routine screening in high-risk groups, particularly women with prior cesareans and a low-lying placenta, becomes increasingly important for catching cases before delivery day.