Placenta accreta

When the placenta grows too deeply within the uterine wall, a condition known as placenta accreta develops. Normally, after childbirth, placenta delivery should follow. In placenta accreta, the placenta stays attached. There are three types of placenta accreta. Placenta accreta is when the placenta just sticks to the wall of the uterus. Placenta increta is when it is embedded deep down in the uterine muscle. Placenta percreta is when it passes through and beyond the uterine muscle.

Last Updated: February 24, 2024

One in every 30,000 pregnancies had placenta accreta in the 1960s, but by the 2000s, that number had risen to one in every 533 births. Prior cesarean delivery is a risk factor for placenta accreta, hence the rise reflects the rise in cesarean deliveries.

Most of the time, a previous cesarean section is linked to placenta accreta spectrum (PAS) disorders. This is likely related to aberrant placentation after cesarean scar decidua loss. Other risk factors include maternal age and multiparity. Placenta accreta is associated with myomectomy, uterine curettage, hysteroscopic surgery, endometrial ablation, uterine embolization, and pelvic irradiation.

Placenta accreta rarely causes any noticeable symptoms. Third-trimester pregnancy (weeks 28-40) is when some women have the most common pregnancy complications, including bleeding and pelvic pain (from the placenta pressing on the bladder or other organs).

Placenta accreta can be detected with a prenatal ultrasound. The depth to which the placenta has crossed the uterine wall can sometimes be viewed by magnetic resonance imaging (MRI).

Occasionally, doctors would not notice placenta accreta until after you've given birth. The placenta should be expelled by uterine contractions within 30 minutes following delivery. If this is not happening, doctors may suspect placenta accreta.

Treatment

Prenatal detection is key for effective management of the placenta accreta spectrum. There are many things that can be done to reduce risks. In order to maximize infant maturity and limit maternal hemorrhage, the American College of Obstetricians and Gynecologists (ACOG) recommends cesarean hysterectomy deliveries occur between 34 0/7 and 35 6/7 weeks of gestation.

However, a hysterectomy (the removal of the uterus) may be the safest option in extreme circumstances if the placenta is deeply attached or intruding into other organs. Having the uterus removed during a cesarean section delivery is known as a cesarean hysterectomy. The baby, uterus, and placenta will all be delivered at the same time. Removing the uterus while it is still linked to the placenta reduces the likelihood of heavy bleeding.

It is impossible to avoid placenta accreta. Multiple cesarean deliveries or a placental abnormality, such as placenta previa, can raise the likelihood of placenta accreta. See a doctor to discuss your risk factors for placenta accreta.

References

Shepherd AM, Mahdy H. Placenta Accreta. [Updated 2022 Sep 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK563288/

Cleveland Clinic (2022). Placenta Accreta. Retrieved November 17, 2022, from https://my.clevelandclinic.org/health/diseases/17846-placenta-accreta

Mayo Clinic (2022). Placenta Accreta. Retrieved November 17, 2022, from https://www.mayoclinic.org/diseases-conditions/placenta-accreta/diagnosis-treatment/drc-20376436

Last Updated: February 24, 2024