Learn All About the Placenta and Placental Abruption

In this article, learn all about the placenta, a temporary organ, as well as placental abruption.
Learn All About the Placenta and Placental Abruption

Last update: 25 September, 2019

Learn all about the placenta and placental abruption in the following article. The placenta is a vital organ that connects mother and baby. It’s the means by which the fetus receives all the necessary nutrients to develop.

Now, it’s said that a woman has a normal placenta when it’s positioned correctly and, therefore, won’t cause any problems if it moves.

As the pregnancy progresses, it’s normal for the placenta to gradually rise until it completely separates from the opening of the cervix. This allows the baby to come out into the world during birth.

How a normal placenta evolves

During pregnancy, this temporary organ matures. These stages of maturity can be checked via ultrasounds. In the following list, we detail each of these stages:

  • Grade 0. This grade corresponds to the first two trimesters of pregnancy. It’s mainly characterized by the fact that the chorionic plate (near the fetus) is the same as the basal plate (near the uterus).
  • Grade I. From week 31, chorionic plate calcifications start to be seen. At this point, the placenta isn’t as homogeneous.
  • Grade II. From week 36 until the end of the gestation process, the placenta is irregular. This is due to calcium deposits, that the basal plate seems to be separated from the myometrium, and that the chorionic plate is corrugated and discontinuous.
  • Grade III. In this stage, the placenta is aged or completely calcified.

Where’s the placenta located?

A baby inside the placenta.

The life of both mother and baby is at risk in cases of placenta accreta.

The placenta is formed by a maternal component called the “chorionic plate” and a fetal placenta known as the “fetal plate.” The first consists of amniotic epithelial cells and a conjunctiva, formed by the axis of the first order villous trunks. As for the second, it consists of syncytiotrophoblast and cytotrophoblast residue, as well as by Nitabuch’s fibrinoid layer.

Between the two plates lies the intervillous space that contains the chorionic villi, which are initially constituted by trophoblastic tissue, which will then become the placenta. The placenta should be located in the back of the uterus.

On the other hand, placenta previa” is when the placenta is located in the lower part of the uterus.

The development of the placenta begins with embryo implantation, when the trophoblast cells penetrate the blood vessels of the uterus and establish a connection between mother and baby.

Placental abruption

Placental abruption is when this temporary organ detaches from the uterus early, before the 20th week of pregnancy and before the third trimester of pregnancy.

This condition can manifest as external or internal bleeding. In the case of the latter, the blood remains between the placenta and uterus.

The most common sign of placental abruption is vaginal bleeding, which is usually not as abundant as in cases of placenta previa.

Risk factors

  • Smoking
  • Leiomyomas or fibroids
  • Trauma
  • Hypertension
  • Maternal age
  • Multiparity
  • Pre-eclampsia
  • Previous cesarean section
  • Chorioamnionitis
  • Bleeding diathesis
  • Thromboembolic disorders
  • Retroplacental hematoma
  • Uteroplacental apoplexy
  • Early placento-decidual degeneration
  • Preterm rupture of membranes
A woman with placental abruption.

Symptoms of placental abruption

The most common symptoms are vaginal bleeding and painful contractions. Generally, the bleeding will depend on the magnitude. However, the blood may build up and remain between the placenta and the uterine wall (occult bleeding).

Other signs are:

  • If it’s mild, the woman may suffer from some bleeding accompanied by cramping.
  • If it’s moderate, heavier bleeding may occur. Cramps and abdominal pain will also be more intense.
  • If more than half of this temporary organ separates, the patient may experience abdominal pain and heavy bleeding. Also, she may suffer from contractions and the baby could move unusually.

In short, the degrees of placental maturity allow doctors to know the development of said organ, which can be seen through an ultrasound. This test allows doctors to analyze whether the pregnancy is developing as it should. If you notice any unusual signs, you must consult a specialist.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.



This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.