The posterior placenta occurs when a mother's placenta attaches to her uterus on the back wall. The placenta is an organ that supplies nutrients and oxygen from the mother's blood to the baby's blood. It covers a wide area and is connected to the mother's uterus. The umbilical cord connects the placenta to the baby.
The frontal area of the uterus is considered the anterior placenta; the rear is the posterior placenta; the fundus constitutes the upper wall of the placenta and the sides of the uterus are the right and left sides.
It does not matter in which area of the uterus the placenta is located, but if the lower portion is too low, it can make it difficult for the baby's head to descend at birth. This can happen when the mother has a posterior placenta.
There is a posterior placenta when the uterus is positioned between the mother's pelvic bones. As the baby begins to grow, so does the uterus. The placenta attaches itself to the uterine wall. When it attaches to the back, it is considered a posterior placenta.
The position of the placenta largely depends on the location of the egg when it has been fertilized. The fertilized egg attaches itself to the wall of the uterus and begins to grow from there.
Possible consequences
The uterus is a muscular, pear-shaped organ nestled in a woman's pelvic bones. During pregnancy, the uterus enlarges as the baby grows. The placenta, an important liver-shaped organ that transfers blood rich in oxygen and nutrients from the mother to the baby, is attached to the inner wall of the uterus.
The placenta may adhere to the front of the uterus, in front of the woman's belly, called the anterior placenta. If the placenta attaches to the back wall of the uterus, it is called the posterior placenta.
The anterior and posterior positions of the placenta are considered normal for the mother and the developing baby.
The concern arises when the placenta develops towards the cervix, called the placenta previa. In such a condition, the placenta could separate from the neck that is narrower and less stable at the bottom of the uterus and complications could result from excessive bleeding or premature delivery.
Both the anterior and posterior placenta are normal for both the baby and the mother. When it is in the vertical position of the uterus, this causes a posterior placenta. When the placenta is on the back wall towards the top of the uterus, it is considered the posterior fundal placenta as it is attached to the fundus of the uterus.
This is considered the best location for the baby, as it allows him to move to the previous position just before he is born. Whereas if it faces the spine of its mother, the crown of the child's head can make its way in the direction of the birth canal.
Ultrasound
When a woman is pregnant, an ultrasound is done to find out exactly where the placenta is and what its location is on the cervix. It is normal for the placenta to change during pregnancy.
In mid-pregnancy, the placenta occupies 50% of the space located on the surface of the uterus. At about 40 weeks, the placenta only occupies 17 to 25% of the surface of the uterus.
It is not that the placenta is shrinking, it means that it grows at different times during pregnancy.
In the third part of pregnancy, the baby's head begins to prepare for delivery by descending into the pelvic area.
The lower part of the uterus begins to contract the pressure that the baby's head is putting on this area. This occurs is when placental attachment seems to be starting to rise.
Previous placenta
When the placenta grows in the direction of the cervix, it is called the placenta previa and this could be a cause for concern. The placenta has a chance to detach itself from the unstable portion of the cervix into the lower part of the uterus, which could cause preterm labor and complications as a result of heavy bleeding.
There is usually nothing to worry about if a scan taken early in your pregnancy determines that your placenta is in the lower part of your uterus, as the placenta will move upward as the pregnancy progresses..
Later in pregnancy, this position of the placenta could cause problems. Placenta previa means that the cervix has become blocked and the baby may not be able to be delivered vaginally except by cesarean section.
Placental abruption occurs when the uterine wall stretches towards the second half of pregnancy, resulting in excessive bleeding.
It is important to monitor the location of the placenta throughout the pregnancy to determine if the mother will be able to deliver her baby vaginally or if she will need a C-section.
Prevention
Mothers rarely detect the position of the placenta, although women with a posterior placenta can feel the baby's movements earlier and stronger than mothers with an anterior placenta.
This is because a posterior placenta fills the back wall of the uterus, forcing the baby forward and closer to the woman's womb, where fetal heartbeat and movements are most easily detected.
Ultrasounds, first used in obstetrics in the 1960s, detect the position of the placenta and the baby's development. Sometimes the placenta will shift as the uterus grows.
Mothers who are diagnosed with placenta previa may find that the placenta has shifted into a posterior placenta or anterior placental position by the time of birth.
References
- New Health Guide ORG. (2014). Posterior Placenta. 2-1-2017, from Health Guide.
- Gill, L.. (2013). A posterior placenta. 2-1-2017, from Baby Center.