Management of Abnormally Invasive Placent

An expert is a person with significant experience in AIP and a high level of knowledge and/or skills relating to the condition.

Expectant outpatient management of women with AIP, even in the presence of placenta previa, is acceptable treatment, as long as the woman is asymptomatic and has been appropriately counseled.

Symptomatic women (eg, those with bleeding, uterine contractions, or other obstetric complications) should be cared for according to local protocols and expertise.

As soon as women are antenatally diagnosed with AIP, they should have their Hb level measured. If it is low (<110 g/L [11 g/dL] before 28 weeks’ gestation or <105 g/L [10.5 g/dL] after 28 weeks’ gestation), appropriate hematinic investigations should be undertaken and if indicated, iron supplementation (oral or intravenous) should be given to optimize their Hb level before surgery.

The timing of delivery should be tailored to each unique set of circumstances and based on the individual woman’s risk of emergent delivery. To reduce the risk of neonatal morbidity, it is reasonable to continue expectant management until after 36.0 weeks’ gestation for women with no previous history of preterm delivery (<36.0 weeks’) and who are stable with no vaginal bleeding, preterm premature rupture of the membranes (PPROM), or uterine contractions suggestive of preterm labor.

In the case of women with history of previous preterm birth, multiple episodes of small amounts of vaginal bleeding, a single episode of a significant amount of vaginal bleeding or PPROM, planned delivery at around 34.0 weeks’ gestation should be considered given the increased risk of emergent delivery.

An individualized approach for antenatal steroid administration should be employed, based on the current local guidelines for the specific gestation at delivery, irrespective of the suspicion or diagnosis of AIP.

The IS-AIP does not recommend undertaking routine preoperative cystoscopy. If preoperative cystoscopy is performed for insertion of ureteric stents, the appearance of the bladder should not change the (imaging- based) plan of management.

Placement of ureteric stents may be beneficial in preventing ureteric injury and early morbidity.

The effect of prophylactic arterial balloon catheters on bleeding and morbidity among women with a prenatal diagnosis of AIP has yet to be confirmed. Significant adverse events have been reported from this procedure. Larger, prospective, appropriately controlled studies are needed to demonstrate both the safety and efficacy of prophylactic balloon occlusion. Given this, the IS-AIP cannot recommend routine use of prophylactic pelvic arterial balloon catheters for all cases of suspected.

When hysterectomy is either planned or likely, the woman should be placed in a position in which the vagina is accessible (such as lithotomy or legs straight on the operating table but parted) to facilitate manipulation of the cervix, if required to assist the hysterectomy. This will also allow easier assessment of any blood lost vaginally.

There is no evidence of benefit for routine use of a vertical midline incision for all cases of antenatally diagnosed AIP. The decision regarding which type of skin incision is used should be made by the operating team. The location of the placenta, degree of invasion suspected, likelihood of intraoperative complications, maternal body habitus, gestational age, and preference of the operating surgeon/obstetrician should all be taken into consideration.

Avoiding placental transection when making the uterine incision is essential if AIP is clearly evident on opening the abdomen, and is reasonable for women with antenatally suspected AIP but with no definite evidence seen at laparotomy, even if it means making an upper segment or fundal incision, as it is likely to reduce maternal blood loss from the placental bed.

If the US scan is undertaken in an appropriately sterile manner, the small theoretical risk of introducing infection is outweighed by the benefit of ensuring the incision is made away from the placental bed. Therefore, intraoperative US of the exposed uterus should be used, where possible, to locate the placental edge and assist decision making regarding the uterine incision site.

When expectant management is planned and AIP confirmed at delivery, forced manual removal of the placenta should not be attempted.

Expectant management appears to be associated with less blood loss and lower transfusion requirements than both hysterectomy and uterus-conserving surgery and will be successful for between 60% and 93% of women, with the remainder undergoing hysterectomy, usually for secondary PPH or infection.

There is no evidence of benefit from the use of methotrexate when the placenta left in situ. As there is evidence for potential significant harm including maternal mortality, the IS-AIP do not recommend the use of methotrexate for conservative management of AIP.

There is no evidence for prophylactic uterine artery embolization increasing efficacy of conservative management, and 2 cases of uterine necrosis have been reported in 2 cohort studies (level 2b evidence). Therefore, the IS-AIP do not recommend prophylactic uterine artery embolization in women undergoing conservative management.

There is, however, some evidence to suggest that attempting local resection may be detrimental in cases involving invasion into the uterine cervix and/or parametrium (level 4 evidence). Therefore, local resection should be considered only where there is no invasion into the parametrium and/or uterine cervix.

The IS-AIP expert consensus of what constitutes an “appropriate case” for local resection is focal disease with an adherent/ invasive area which is <50% of the anterior surface of the uterus.

Tranexamic acid should be administered whenever massive hemorrhage occurs, preferably as soon as possible after onset of significant bleeding.

Women wishing to preserve their fertility should be counseled that this is possible.

If conservative management is successful, the subsequent pregnancy rate is between 86% and 89%.

Women wishing for fertility preservation should be managed by a team with appropriate resources and experience in conservative management according to that team’s local protocols.