What is « abnormally invasive placenta » (AIP)?
The placenta develops along with the baby in the uterus (womb) during pregnancy. It connects the baby with the mother’s blood system and provides the baby with its source of oxygen and nourishment. The placenta is delivered after the baby, and is also called the afterbirth.
Rarely, placenta development may be complicated by a problem known as AIP or placenta accreta. This is when the placenta grows into the muscle of the uterus, making separation at the time of birth difficult. AIP is more commonly found in women with placenta praevia (placenta cover a part or all of the cervix) who have previously had a caesarean section.
AIP may be suspected in the antenatal period by an ultrasound scan, but while additional tests such as magnetic resonance imaging (MRI) scans may help with the diagnosis, your doctor will only be able to tell for sure if you have this condition at the time of your caesarean section.
AIP causes bleeding when an attempt is made to remove your placenta. The bleeding may be severe and you may require a hysterectomy (removal of the womb) to stop the bleeding. It may be possible to leave the placenta in place after birth, to allow it to absorb over a few weeks and months. Unfortunately this latter type of treatment is not always successful and some women will still need a hysterectomy.
If AIP is suspected before your baby is born, your doctor will discuss your options and the extra care that you will need at delivery. Delivery may be planned earlier – for example between 35 and 36 weeks, depending on individual circumstances. You may need to have your baby in a hospital, which has additional facilities such as interventional radiology available. Your doctor will discuss this with you.
(based on the information found under RCOG Patients information "A low-lying placenta after 20 weeks")