Placental Disorder Conditions

What is placenta accreta spectrum?

Placenta accreta spectrum is a term used to describe the ways in which an expectant mother’s placenta can become abnormally attached to the uterine wall. The placenta should normally come away from the uterus as the child is born. With placenta accreta, increta, and percreta, the placenta does not fully separate from the uterus during birth, which can lead to heavy and dangerous levels of blood loss during delivery. These conditions are all high-risk complications of pregnancy.

• Placenta accreta. A serious condition in which the placenta grows more deeply into the uterine wall than it should and becomes too firmly attached.
• Placenta increta. A severe condition, in which the developing placenta attaches and grows into the muscles of the uterine wall.
• Placenta percreta. A high-risk condition in which the growing placenta becomes attached to the uterine wall and actually grows through it, sometimes into the colon, the bladder, or other nearby organs.

A related condition is placenta previa.

How common is placenta accreta spectrum?

Placenta accreta was once a rare condition, but the rate has quadrupled since the 1980s. Experts estimate that it now occurs in about 1 in 272 pregnancies, which they attribute to the growing rates of cesarean delivery in the past 30 to 40 years.

Lucile Packard Children’s Hospital Stanford has developed a dedicated program in placental disorders to help manage this increased number of patients and to give them the expert and individualized attention and care plan they need.

What causes the disorders on the placenta accreta spectrum?

Placenta accreta is related to abnormalities in the uterine wall. This is often due to scarring following a cesarean delivery or other surgery in the area. However, placenta accreta can rarely happen on its own, with no apparent cause. 

What are the risks factors for placenta accreta?

• The level of risk grows based on the number of cesarean deliveries.
• If you have a history of cesarean delivery and/or placenta previa (a related condition in which the placenta partially or entirely covers the cervix because it lies too low in the uterus), you are at the highest risk of accreta.
• If you have placenta previa and a history of two cesarean deliveries, you have a risk of developing accreta as high as 40%.
• If you are over age 35 and have given birth previously (whether cesarean or not), you are at a higher risk of placenta accreta.

What are symptoms of placenta accreta?

There are few external symptoms of these conditions. In some cases, there is vaginal bleeding during the second or third trimester. This is usually painless. 

How is placenta accreta diagnosed?

The condition is diagnosed primarily by ultrasound. At Packard Children’s Hospital, maternal-fetal medicine (high-risk obstetrics) specialists have vast experience in evaluating ultrasounds using algorithms created by our own team specifically to evaluate these conditions.

What is the treatment for placenta accreta?

• If you have confirmed accreta, our approach at Packard Children’s Hospital is to schedule a combined cesarean delivery and hysterectomy between 34 and 37 weeks into pregnancy if you haven’t shown bleeding, signs of early labor, or any other complications. Surgery is performed by an experienced team composed of specialists in maternal-fetal medicine, gynecologic oncology, and obstetric anesthesia, among others.
• However, up to 30% to 50% of women with these conditions will deliver earlier than planned, due to bleeding or early labor. You should plan for early hospitalization if you are experiencing these symptoms or if you need to travel a significant distance to get to our hospital.
• The major complication of accreta is hemorrhage, which can be rapid and severe.