Placenta accreta spectrum: Risk factors, diagnosis and management with special reference to the Triple P procedure

Abstract

Abnormal invasion of placenta or placenta accreta spectrum disorders refer to the penetration of the trophoblastic tissue through the decidua basalis into the underlying uterine myometrium, the uterine serosa or even beyond, extending to pelvic organs. It is classified depending on the degree of invasion into placenta accreta (invasion <50% of the myometrium), increta (invasion >50% of the myometrium) and percreta (invading the serosa and adjacent pelvic organs). Clinical diagnosis is made intra-operatively; however, the confirmative diagnosis can only be made after a histopathological examination. The incidence of abnormal invasion of placenta has increased worldwide, mostly as a consequence of the rise in caesarean section rates, from 1 in 2500 pregnancies to 1 in 500 pregnancies. The importance of the disease is due to the increased maternal and foetal morbidity and mortality. Foetal implications are mainly due to iatrogenic prematurity, while maternal implications are mostly the increased risk of obstetric haemorrhage and surgical complications. The average blood loss is 3000-5000 mL, and up to 90% of the patients require a blood transfusion. An accurate and timely antenatal diagnosis is essential to improve outcomes. The traditional management of abnormal invasion of placenta has been a peripartum hysterectomy; however, the increased incidence and the short- and long-term consequences of a radical approach have led to the development of more conservative techniques, such as the intentional retention of the placenta, partial myometrial excision and the 'Triple P procedure'. Irrespective of the surgical technique of choice, women with a high suspicion or confirmed abnormally invasive placenta should be managed in a specialist centre with surgical expertise with a multi-disciplinary team who is experienced in managing these complex cases with an immediate availability of blood products, interventional radiology service, an intensive care unit and a neonatal intensive care unit to optimize the outcomes.

Keywords: Triple P procedure; intentional retention of placenta; peripartum hysterectomy; placenta accreta spectrum disorders; placenta percreta; prophylactive endovascular occlusive balloons; the ‘smudged egg’ sign.

Conflict of interest statement

Declaration of conflicting interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship and/or publication of this article.

Figures

Figure 1.

The ‘St George’s Boat Incision’ on the rectus sheath. Note the flap allows access to the myometrium above the upper border to the placenta.

Figure 2.

Anterior wall uterine defect after myometrial excision. Note approximately 2 cm lower myometrial margin to facilitate closure.

Figure 3.

Application of the white powder, the PerClot (local haemostat) to the areas of bladder invasion.

Figure 4.

Second-layer closure of the myometrial defect. Note the use of three ‘box sutures’ with a 110-mm needle to close the first layer without tension, prior to continuous second-layer closure.

Figure 5.

A cornual placenta percreta at the site of excision of previous cornual ectopic pregnancy.

Figure 6.

Placenta percreta invading one of the horns of a bicornuate uterus.

Figure 7.

Myometrial excision of area of placental invasion in the upper segment after bilateral ligation of uterine arteries.