A placenta creta, accreta, increta, or percreta is a placenta that grows during pregnancy into or through the uterus. Having this condition is life-threatening and requires expert surgical and medical care.

Normally during pregnancy, the placenta attaches to the uterine wall and is separated from the uterus by the Nitabuch fibrinoid layer (named after Raissa Nitabuch who was among the first women who graduated from medical school in Bern, Switzerland, and who first described the basal layer of the placenta in her dissertation about the human placenta). Sometimes though, the Nitabuch fibrinoid layer is thinned or missing, and the placenta will attach itself too deeply into the uterine wall, this is called a placenta creta.

Depending on how deep the placenta invades the uterus, placenta creta can present itself in three different forms:

• Placenta accreta
• Placenta increta
• Placenta percreta

A placenta creta is present in about 1 in 2500 pregnancies today. Read on to find out more about each placenta condition, what it means for you, and what it means for your unborn child.

Read more about high-risk pregnancy complications

Placenta accreta

This is the most common form of placenta creta issues, where the placenta attaches to the uterine wall but does not attach deeply enough to affect the uterine muscle. 

In a placenta accreta, the typical Nitabuch fibrin layer is missing between the placenta and the uterus. This happens in about 75% of all the pregnancies that experience an issue with placenta attachment.

Placenta increta

This occurs within 15% of cases and happens when the placenta attaches itself so deeply into the uterine wall that it attaches to the uterine muscle. 

Placenta percreta

A placenta percreta is the least common type of the placenta creta conditions, presenting itself in about 5% of all these cases. This occurs when the placenta attaches itself so deeply that it attaches to another organ, such as the bladder.

Causes

The exact cause of this placenta condition is unknown, but evidence shows that it can be related to placenta previa, and previous C-section deliveries. Placenta previa is a condition that occurs in about 1 out of 200 pregnancies, and is a condition where the placenta lies low in the uterus and partially or completely covers the cervix. This could cause the placenta to bleed and detach from the uterine wall when the cervix and the lower portion of the uterus change. 

About 5-10% of women who experience placenta previa will experience placenta accreta in a subsequent pregnancy. In roughly 60% of the cases placenta accreta, multiple C-section deliveries were present.

With a placenta previa and one prior C-section delivery, there is an about 25% chance of an accreta, with a placenta previa and two prior C-sections, the chance of an accreta is about 50%, and with a placenta previa and three or more C-sections, the chance of an accreta is 75+%.

Risks to the fetus

Placenta accreta (or increta, or percreta) can result in a premature birth and complications associated with a premature birth could easily arise. Your healthcare professional will be able to examine you and determine the best course of action to take in order to keep the pregnancy going as close to full term as possible. A warning sign that this condition may exist is bleeding during the third trimester.

Risks to the mother

The primary concern is that the mother hemorrhages during delivery and subsequent attempt to separate the placenta from the uterine wall. Hemorrhaging can be life threatening to the mother if it becomes severe. Other concerns are damage to the uterus and surrounding organs. When the placenta attaches too much to the uterus, only a hysterectomy, the removal of the uterus with the placenta attached, can save the mother's life and prevent too much bleeding.

Can you prevent these conditions?

Unfortunately, nothing can be done to prevent the occurrence of this condition. Once diagnosed, you will be monitored very closely by your healthcare professional, and you may undergo surgery to attempt to save the uterus, or do a hysterectomy and remove it altogether. The best thing you can do if you have been diagnosed with this condition is to rest and relax. Talk to your doctor for the best course of action, and try to remain calm.