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Placental & bleeding Call your provider

Placenta accreta

Also known as Placenta accreta spectrum, PAS. Diagnosed in pregnancy, delivered early by plan (around 34 to 36 weeks).

Normally the placenta peels away cleanly within minutes of birth. In placenta accreta it has grown too deeply into the uterine wall and stays anchored, so pulling it free can cause severe bleeding. It usually causes no symptoms during pregnancy and shows up on ultrasound, most often in someone with a prior cesarean. A safe outcome turns on planning: a scheduled delivery at a specialized center with a team ready for it.

Know the warning signs When to call a provider
How common
About 1 in 272 to 1 in 533
Rising along with cesarean delivery rates.
When
Found in pregnancy
Delivered early by plan, often around 34 to 36 weeks.
Urgency
Call your provider
Usually managed by a planned delivery; report any bleeding.
Outlook
Best with a specialized team
Planning ahead is what gives this serious condition a good outcome.

Understanding it

What is placenta accreta?

Placenta accreta spectrum describes a placenta that attaches too firmly and grows too deeply into the uterine wall, so it will not separate normally after birth. The spectrum is graded by depth: accreta attaches to the muscle, increta grows into the muscle, and percreta grows clear through the wall, sometimes into a nearby organ like the bladder. All three share one central danger, bleeding when the placenta will not let go.

It has grown far more common, from about 1 in 30,000 pregnancies in the 1960s to roughly 1 in 272 to 1 in 533 today, tracking the rise in cesarean deliveries. A cesarean leaves a scar, and if the placenta later implants low over that scar, as a placenta previa, it can anchor into muscle instead of lining. Previa accompanies about 80% of accreta cases, and the risk climbs with each added cesarean.

During pregnancy it usually causes no symptoms and is found on ultrasound, sometimes with an MRI to judge how deep it goes; occasionally it bleeds in the third trimester. The real danger arrives at delivery, when the placenta will not separate and heavy, rapid bleeding follows. It is now a leading cause of severe maternal bleeding and emergency hysterectomy.

Planning changes the outcome more than anything else. Known in advance, delivery is scheduled before labor or bleeding starts, at a hospital with an experienced team and blood ready. The usual approach is a cesarean followed by removing the uterus, a hysterectomy, with the placenta left in place rather than pulled off. It is major surgery and usually ends fertility, but delivering this way, on a plan, turns a dangerous condition into a survivable one.

Symptoms

What are the symptoms?

Accreta usually causes no symptoms during pregnancy and is found on ultrasound. It is managed by a planned delivery rather than by waiting for symptoms, but report any bleeding.

Early signs

  • Usually no symptoms during pregnancy
  • Sometimes painless vaginal bleeding in the third trimester
  • Often found on ultrasound because of risk factors such as a prior cesarean and a low-lying placenta

Emergency signs — call 911

  • Any vaginal bleeding during pregnancy, which should prompt an immediate call
  • Heavy vaginal bleeding, which means going to the hospital right away
  • Signs of significant blood loss, such as feeling faint, dizzy, or having a racing heart

Why it matters

Risks to you and baby

Severe bleeding at delivery

The central danger. When the placenta will not separate, bleeding can be sudden and heavy, often needing a transfusion. It is a leading cause of severe maternal blood loss.

Hysterectomy and loss of fertility

The standard, safest treatment is usually to remove the uterus with the placenta still in place, stopping the bleeding but ending the ability to carry future pregnancies.

Injury to nearby organs

In the deepest form, percreta, the placenta can grow into the bladder or other organs that may be injured during surgery. One more reason a specialized surgical team matters.

Preterm birth

Because delivery is planned early to avoid an emergency, babies often arrive several weeks before the due date. Steroids are given ahead of time to help their lungs.

Why planning matters

Nearly every one of these risks shrinks when accreta is diagnosed ahead of time and delivery is scheduled at a center prepared for it. That is the single biggest lever on the outcome.

How it's found

How is it diagnosed?

Accreta is usually found on ultrasound during pregnancy, sometimes confirmed with MRI, and is often suspected in advance from risk factors like a prior cesarean and a low-lying placenta.

Ultrasound

The primary tool. It can show the placenta growing abnormally into the uterine wall, and it is accurate in experienced hands.

MRI

Used when ultrasound is unclear, or to judge how deep the placenta has grown and whether nearby organs are involved.

Risk-factor review

A prior cesarean combined with a low-lying or previa placenta raises suspicion and prompts a careful look at where the placenta attaches.

Usually in the second half of pregnancy, especially with a prior cesarean and a low placenta. Knowing in advance is what allows a safe, planned delivery.

Treatment

How is it managed?

The heart of care is planning: delivering at a specialized center with an experienced team, before labor or bleeding starts, usually by a scheduled cesarean and often a hysterectomy.

Treatment paths

A multidisciplinary team (obstetrics, anesthesia, surgery, and the blood bank) coordinates care at a hospital equipped for major bleeding. Delivery is scheduled before labor, usually a cesarean followed by hysterectomy, with the placenta deliberately left in place, since prying it off can cause massive bleeding. Blood is readied for transfusion.

Monitoring

Repeat ultrasounds track the placenta, any bleeding is assessed urgently, and the delivery is planned in detail well ahead.

Can it recur?

For most people the standard treatment is a hysterectomy, which ends future pregnancy, so recurrence does not apply. Where the uterus is preserved (conservative management), accreta can return, roughly one in five, and any future pregnancy carries serious risk. These choices are made carefully with a specialist team.

What you can do

Can it be prevented?

  • Avoid medically unnecessary cesareans

    The biggest population-level lever is limiting avoidable cesareans, since each one raises the risk in a future pregnancy. It is a reason to weigh a first cesarean carefully when there is a choice.

  • Get diagnosed ahead of time

    No medicine prevents accreta once it is present, but diagnosing it before birth allows a planned delivery at a specialized center, which is what most improves safety.

  • Deliver where the team is ready

    If accreta is suspected, delivering at a hospital with an experienced team and blood bank, rather than the nearest one, meaningfully lowers the risk of a bad outcome.

Who is more at risk

Risk factors

A prior cesarean
The dominant risk factor, climbing with each prior cesarean, especially when the placenta lies over the scar.
With placenta previa, the risk rises roughly from 3% with none to 40% or more after three cesareans
Placenta previa
A low placenta covering the cervix is present in about 80% of accreta cases and is a major risk factor on its own.
Other uterine surgery
Prior fibroid surgery, a D&C, or scarring inside the uterus (Asherman syndrome) can also predispose to accreta.
Age and prior pregnancies
Advanced maternal age and having had several pregnancies add to the risk.
Assisted reproduction
Pregnancies conceived through IVF have a somewhat higher rate of accreta.

Do not wait

When to call your provider or 911

  • Call your provider immediately for any vaginal bleeding during pregnancy, and go to the hospital right away if it is heavy.
  • Seek emergency care for signs of significant blood loss, such as feeling faint, dizzy, or having a racing heart.
  • If you have had a cesarean and this pregnancy has a low-lying placenta, ask your provider whether you should be evaluated for accreta.
  • Keep all recommended ultrasound appointments, which track the placenta and plan your delivery.
  • Confirm where you will deliver, since a specialized center with an experienced team is safest if accreta is suspected.

Talking to your team

Questions to ask your provider

  • How confident are you in the diagnosis, and how deep does the placenta appear to grow?
  • Should I deliver at a specialized center with a multidisciplinary team?
  • Will I likely need a hysterectomy, and what does that mean for future pregnancies?
  • When are you planning my cesarean, and will I get steroids for my baby's lungs?
  • What is the plan if I start bleeding before the scheduled date?
  • Given my history, what raises or lowers my risk in the future?

Keep reading

More on placenta accreta

All pregnancy guides articles

Good to Know

Placenta accreta FAQs

Common questions about placenta accreta, answered.

What exactly is placenta accreta?

It is a placenta that grows too deeply into the uterine wall and will not separate normally after birth. By depth it is called accreta (into the muscle's surface), increta (into the muscle), or percreta (through the wall, sometimes into the bladder). The shared danger is heavy bleeding when it will not detach.

Will I need a hysterectomy?

In most cases, yes. The safest way to control the bleeding is usually to remove the uterus with the placenta left in place. It is major surgery and ends fertility, hard news, but often what protects your life. Uterus-sparing options exist in selected cases and are discussed with a specialist team.

Why do I have to deliver early and at a special hospital?

Delivering on a set schedule, before labor or bleeding starts, at a center with an experienced team and blood ready, sharply lowers the risk of a life-threatening emergency. That is why an early, coordinated delivery is recommended.

I have had a cesarean and my placenta is low. Am I at risk?

That specific combination, a prior cesarean plus a low or previa placenta over the scar, is the highest-risk situation for accreta. It is exactly what your provider looks for, and it should prompt a careful ultrasound and a delivery plan.

Is my baby going to be okay?

Usually, yes. The main risk is prematurity, since delivery is planned early to keep you safe. Steroids given ahead of time help your baby's lungs, and babies born at 34 to 36 weeks generally do well.

Can placenta accreta be prevented?

Once it is present, no medication prevents it. Across the population, avoiding medically unnecessary cesareans lowers future risk, since each one adds to it. For an affected pregnancy, the best protection is diagnosing it early and planning delivery at a specialized center.

Can I have more children afterward?

If treatment involves a hysterectomy, the usual approach, then no. In selected cases the uterus can be preserved, but future pregnancies then carry serious risk, including a real chance of accreta returning. These decisions are made individually with specialists.

What symptoms should I watch for?

Often there are none during pregnancy. Some people have painless vaginal bleeding in the third trimester. Report any bleeding right away, but know the plan is a scheduled delivery, not waiting for symptoms.

Medically Reviewed · Updated

Reviewed by Dr. Grace Lin, MD, FACOG · OB-GYN

Obstetrician-gynecologist focused on reproductive and sexual health for women: pregnancy, BV, yeast, trichomoniasis and HPV/cervical screening. Our editorial guidelines →

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