|Risk of Abnormal Placental Placement Following C/S
There is an association between C/S delivery and abnormal placental position and growth in subsequent pregnancies. This risk begins following the first C/S and increases with each subsequent C/S, especially after 4 C/S. Therefore, it is important to consider this risk in women wanting to have large families.
The incidence of placenta previa (placenta covering the cervix) significantly increases in women with each additional C/S delivery:
- One C/S: 0.9%
- Two C/S: 1.7%
- Three: 3.0%
- Four: 10%
The presence of placenta previa is also associated with an increased incidence of placenta accreta, increta, and percreta.
Under normal circumstances, the placenta attaches to the uterine wall in the upper portion of the uterus (fundus) and it does so like a suction cup without deeply penetrating into the uterine tissue or muscle. Placenta Accreta, Increta and Percreta are all abnormal and potentially life threatening attachments of the placenta into muscle and sometimes through the entire uterine wall to include adjacent organs such as the bladder and rectum.
Placenta accreta is an invasion of the myometrium which does not penetrate the entire thickness of the uterine muscle. It is the most common form of the condition and accounts for 75-78% of cases.
Placenta increta occurs when the placenta further extends into the myometrium, penetrating deeper into the muscle. This represents 17% of cases.
Placenta percreta represents the worst of this condition, when the placenta penetrates the entire myometrium through the entire uterine wall. This variant can lead to the placenta attaching to other organs such as the rectum or bladder. This represents 5-7% of cases.