What is placenta accreta: main causes and complications 2026

During pregnancy, the placenta adheres to the uterine wall, detaching and being expelled later after the baby is born (that is, after delivery). However, placenta accreta is a serious pregnancy complication that can occur when the placenta adheres extremely deeply to the wall of the uterus. What does it consist of, what symptoms does it produce, what are its causes and what complications may arise?

What is placenta accreta? What does it consist of?

The placenta is a wonderful organ, essential for the development and evolution of pregnancy. Without it, life is not possible, and it is essential in pregnancy by becoming a vital connection between the mother and the growing baby. Among its important functions, it is responsible for transmitting the necessary nutrients to the fetus, eliminating the baby's waste, supplying it with oxygen and manufacturing essential hormones so that the pregnancy can continue.

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It begins to form from the moment the embryo is implanted in the uterine wall, something that occurs around 7 days after conception/fertilization has occurred, from the same cells coming from both the sperm and the egg that have also allowed the development of the fetus.

When the embryo reaches the uterus and implants (nestles in the endometrium), the trophoblast and amnioblast are formed. While the amnioblast is the inner layer that gives rise to the embryo, the trophoblast is its outer layer, which will eventually give rise to the placenta. This evolves into chorionic villi, which are inserted into the maternal tissue in the same way as if they were the roots of a tree, adhering to the womb wall.

Placenta accreta, also known medically as placental accreta, is a serious condition that occurs during pregnancy. It occurs when the placenta adheres deeply to the uterine walls. Thus, although the placenta commonly detaches from this wall after the baby is born, if placenta accreta exists, it is possible that part or all of the placenta remains attached to the uterus after delivery, which can cause serious blood loss.

Why is it so serious? What are its complications?

Placenta accreta is considered a potentially fatal pregnancy complication, especially if this type of placenta is not detected until the time of delivery.

However, in most cases, women with placenta accreta are diagnosed at some point during pregnancy, so when it comes time to deliver, doctors will usually perform an early cesarean section, then remove the woman's uterus, a procedure known as a hysterectomy.

What are its causes?

It is not known exactly what causes placenta accreta. However, doctors believe it may be related to existing irregularities in the uterine lining, and elevated levels of alpha-fetoprotein, a protein produced by the baby, which can be detected in the mother's blood.

When there are irregularities in the lining of the uterus, these may be due to previous uterine surgery, or a previous cesarean delivery. The presence of these scars allows the placenta to grow deep into the uterine wall.

But in some cases, placenta accreta occurs in women who have no history of placenta previa, cesarean delivery, or uterine surgery, and the real reasons why this complication arises are not known.

How is it diagnosed?

As we mentioned in a previous section, sometimes the placenta accreta appears during childbirth, which means that it could not have been previously found by the doctor.

However, sometimes the presence of this placenta is diagnosed during routine ultrasound tests. These are common tests that allow you to verify the presence of placenta accreta. And if there are some known risk factors, it is possible to perform a blood test to study whether there are - or not - high alpha-fetoprotein values.

What is the treatment like? How is placenta accreta treated?

We must keep in mind that, in reality, each case of placenta accreta is different, but if the doctor has been able to diagnose the presence of this type of complication at some point during the pregnancy (and, therefore, before delivery), he will create a plan to ensure that the baby is born safely.

Severe cases of placenta accreta are treated by surgery. First, doctors perform a cesarean delivery to deliver the baby.

Secondly, they can perform a hysterectomy (removal of the uterus) as a preventive measure to avoid serious blood loss, which can occur when part or all of the placenta remains attached to the uterus after childbirth.

When a woman wants to become pregnant again in the future, there is a treatment option that can help preserve fertility. It consists of a surgical procedure in which a large part of the placenta is left in the uterus. However, these women may be at higher risk of complications.