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Canberra Hospital and Health ServicesClinical Guideline Placenta Praevia and Abnormally Invasive Placenta (AIP)Contents

Contents....................................................................................................................................1

Guideline Statement.................................................................................................................2

Alert.......................................................................................................................................... 2

Scope........................................................................................................................................ 2

Section 1 – Background.............................................................................................................2

Section 2 – Antenatal care of the woman with suspected Placenta Praevia or Abnormally Invasive Placenta.......................................................................................................................3

Section 3 – Pre-operative management of AIP.........................................................................5

Section 4 – Emergency surgery.................................................................................................6

Section 5 – Operative day.........................................................................................................7

Implementation........................................................................................................................ 8

Related Policies, Procedures, Guidelines and Legislation.........................................................8

References................................................................................................................................ 8

Definition of Terms...................................................................................................................9

Search Terms............................................................................................................................ 9

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Guideline Statement

This purpose of this guideline is to provide clinical direction for the care of women with an abnormally invasive placenta (AIP). Commonly used synonyms include Morbidly Adherent Placenta (MAP) or placenta accreta.

Alert

Women with morbidly adherent/invasive placentation are potentially at very high risk of serious morbidity and therefore a high level of consultant involvement is required.

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Scope

This document applies to Canberra Hospital Health Services (CHHS) staff working within their scope of practice including but not limited to: Medical Officers Registered Nurses and Midwives Students working under supervision sonogaphers/interventional radiologists

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Section 1 – Background

Placenta praevia exists when the placenta is implanted wholly or partly into the lower segment of the uterus. Abnormal invasion of the placenta (AIP) to the uterine wall is a potentially life threatening obstetric complication that frequently require interventions such as caesarean hysterectomy and high volume blood transfusion.

IncidencePlacenta praevia occurs in 0.3-0.5% of all pregnancies. The incidence of placenta praevia andAIP along with its complications is increasing due to increasing incidence of caesarean section (CS) combined with increasing maternal age.

Classifications:Placenta PraeviaPlacenta praevia exists when the placenta is inserted wholly or in part into the lower segment of the uterus.

It is classified by ultrasound imaging: if the placenta lies over the internal cervical os, it is considered a major praevia (Grades 3 – 4).

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If the leading edge of the placenta is in the lower uterine segment but not covering the cervical os, minor or partial praevia exists (Grades 1- 2).

Abnormally Invasive Placenta (AIP)Placenta accreta Placenta implants totally/partially/focally through the decidua basalis Villi attached to myometrium

Placenta increta Villi invade the myometrium

Placenta percreta Villi fully penetrate the myometrium May breach the serosa and invade surrounding structures

Risk Factors Previous uterine surgery – Caesarean section, uterine curettage, myomectomy Previous retained placenta Advanced maternal age

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Section 2 – Antenatal care of the woman with suspected Placenta Praevia or Abnormally Invasive Placenta

Ultrasound Imaging:Ultrasound does not diagnose all cases of abnormally invasive placenta and it needs to be suspected in the context of a low lying placenta where there has been a previous caesarean section

Anomaly ultrasound scan should include placenta localisation. If there is suspicion of low lying placenta, a transvaginal scan should be performed to confirm the diagnosis. Transvaginal ultrasound is safe in the presence of placenta praevia and is more accurate than transabdominal ultrasound in locating the placenta.

A further transvaginal scan is required for all women whose placenta reaches or overlaps the cervical os at their anomaly scan as follows: In cases of asymptomatic suspected minor praevia, follow-up imaging can be left until

36 weeks gestation In cases with asymptomatic suspected major placenta praevia or accreta, ultrasound

scan should be performed at 32 weeks, to clarify the diagnosis and allow planning for third trimester management and birth

For women who have previously had a caesarean section, it is important to rule out AIP especially when there is anterior placenta praevia

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In cases of symptomatic women, imaging should be performed as appropriate

Diagnosis of the Abnormally Invasive PlacentaAny woman with vaginal bleeding after 20 weeks of gestation, a high presenting part, an abnormal lie in the 3rd trimester or painless and unprovoked bleeding should raise the suspicion of placenta praevia irrespective of previous imaging results.

Colour flow Doppler ultrasonography should be performed in women with a placenta praevia who are at increased risk of placenta accreta; with previous studies estimating sensitivity around 92% and specificity of 68%. MRI and Doppler ultrasound are equally effective in detecting the morbidly adherent placenta. MRI is helpful in detecting the depth of infiltration in cases of morbidly adherent placenta, especially when there is lateral or posterior invasion. Definitive diagnosis of the type of the morbidly adherent placenta is made intraoperatively and histologically.

Antenatal Care The consultant obstetrician, with the respective team, should assume overall

responsibility for decision making and co-ordination with the multidisciplinary team for on-going care and planning for delivery

For all cases of placenta praevia, ultrasound reports should specify whether or not there are features of placenta accreta. If this is not specified, the ultrasound is to be repeated. This scan should be performed by a senior member of the ultrasound service and reviewed by the lead Fetal Medicine Unit (FMU) Obstetrician

A further scan with a senior member of the FMU team present should be considered to assist with surgical planning

Once diagnosed, women are to be reviewed and counselled by a senior consultant obstetrician either on the day of diagnosis or at the earliest possible appointment time.

All relevant stakeholders should be contacted and the appropriate referrals made The woman’s details should be added on to the Antenatal High Risk list so that on-going

discussions and monitoring of plans can be made The woman’s haemoglobin levels and iron stores should be checked and optimised prior

to surgery As with all women at risk of major obstetric haemorrhage, those with suspected AIP

should be encouraged to remain close to the Centenary Hospital for Women & Children (CHWC) for the duration of the third trimester of pregnancy.

Both an elective and an emergency plan should be devised and clearly documented The timing of the caesarean section should consider the desirability of performing it as

an elective rather than an emergency procedure. Elective caesarean section is recommended at 38 – 39 weeks of gestation for

uncomplicated placenta praevia and from 34 - 37 weeks for AIP Steroids may be administered as prescribed if required The management plan is to be formulated by the obstetric team in consultation with

medical imaging, operating theatres and other teams as needed

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Women with features of AIP are to be referred to and counselled by the consultant obstetrician to discuss the delivery plans. Hysterectomy should always be discussed and documented as a potential outcome

Surgical bookings and theatres should be contacted to book an available morning operating list

Patients should be referred for anaesthetic review once the surgical plan has been determined

There is no evidence to support the use of autologous blood transfusion for placenta praevia. Cell salvage may be considered in cases at high risk of massive haemorrhage; discuss with anaesthetist

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Section 3 – Pre-operative management of AIP

Elective Surgical Procedure This requires complex multi-disciplinary involvement that relies on excellent communication

ObstetricsAn experienced senior obstetrician supported by a second obstetrician will manage the delivery.

Gynaecology Theatre Nurse and Midwifery Team Leader of BirthingAn elective caesarean section should be booked to occur between 34 and 37 weeks gestation, (usually 36 weeks) depending on individual clinical situationin order to avoid labour and an emergency procedure.Book cell saver if massive obstetric haemorrhage is anticipated. Indicate the requirement of this in the Request for Admission (RFA) form.

Surgical BookingsComplete an elective caesarean section booking form (RFA) and inform surgical bookings that the procedure is being booked. This is usually booked as an extra list with no disruption to the elective caesarean section list.

Inform antenatal ward of planned admissionContact person: CMC Antenatal Ward.

Interventional RadiologyReview the films (ultrasound and/or MRI) with the lead obstetrician and radiologist, confirming the site of the placenta, the site of the suspected myometrial invasion and if it is possible to ascertain if there is bladder or lateral involvement. This also helps to determine uterine incision site (to avoid placenta injury if possible).Once a date for the planned caesarean section has been confirmed, book interventional radiology for insertion of iliac artery balloons. This booking is made online.

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UrologyRefer to specialist urologist for flexible cystoscopy and consideration of ureteric stenting and possible involvement with delivery if appropriate

AnaesthesiaArrange preoperative anaesthetic consultation and for a decision as to the number of cross-matched units of blood required and the use of cell-salvage.

HaematologyDate and time of procedure, advice may be required.

ICURequest to book an ICU bed, ensure ICU aware of date and time of procedure

Neonatal teamDate and time of procedure, to be notified for a NICU bed. Arrange antenatal consultation with Neonatologist if less than 32 weeks gestation

Vascular SurgeryDate and time of procedure, assistance may be required.

Gynaecology OncologistDate and time of procedure, assistance may be required.

Womano Counsel the woman and her family about the suspected diagnosiso Discuss the need for operative birth and the timingo The option of prophylactic interventional radiologyo The implications in terms of hysterectomy, massive blood loss, cell salvage and blood

transfusiono The type of surgery will depend on the location and degree of the abnormal

implantation of the placenta. This could range from conservative surgery to excising the placental implantation site with primary repair of the uterus to hysterectomy

o Immediate care of her baby after birth

Conservative management of placenta praevia or AIP can be considered as an option and can preserve fertility. This decision should be made after careful counselling regarding the risk of life threatening haemorrhage and hysterectomy.

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Section 4 – Emergency surgery

Emergency Surgical Procedure A small percentage of women with AIP may present with bleeding and require emergency surgery. It is expected that much of the preparation would have been completed. The obstetric team will refer to the checklist and inform appropriate personnel as below.

Inform the 1st and 2nd on-call obstetric consultants Inform the on-call anaesthetic consultant Inform the theatre co-ordinator and request appropriate staff Notify NICU

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Inform the on-call transfusion scientist at the Blood Bank (ext 44239) Alert the on-call urologist and vascular surgeon Notify the ICU of the potential post-op admission

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Section 5 – Operative day

Pre-operative All preoperative preparation should be performed by the obstetric team in accordance

with elective caesarean section pathway The woman should be admitted to the ward at least 24 hours before scheduled surgery

to facilitate adequate and timely preparation The woman is encouraged with antenatal expression of colostrum with obstetric

consultation Ensure pathology collected including blood cross matching Liaise with urologist for cystoscopy and ureteric stent insertion. If iliac artery balloon placement anticipated, liaise with Interventional radiologist Order MRI and discuss results with Radiologist

Day of Surgery Ensure urinary catheter has been inserted prior to transfer to Interventional Radiology

Department On arrival in Interventional Radiology continuous CTG commenced If required, iliac artery balloons are placed before transfer to theatre Woman is transferred from Radiology to Theatre. Anaesthetic administered (usually spinal initially). Depending on clinical circumstances

the decision may be made to convert to general anaesthetic. Fetal monitoring continues as per obstetric consultation. Neonatal team is aware to attend surgery including Registrar and retrieval nurse Midwife provides routine intra-operative care Depending on the woman’s condition she may be transferred to Recovery, then to

Interventional Radiology for balloon removal. If there has been significant bleeding and she is haemodynamically unstable she may be transferred to ICU

Where the baby is cared for will depend on gestation and the individual clinical situation and will be at the direction of the Neonatology team.

When stabilised the woman is admitted to the Antenatal ward Repeat pathology as required Intraperitoneal drain and IDC out as per surgeons recommendation Ureteric stents to be removed as per urologist recommendation Routine postoperative care and postpartum care will be provided as per the woman’s

clinical situation Care should be taken to provide a debrief if required including referral to social work Breastfeeding and expressing are supported as required Routine care is provided for the baby as per relevant Guidelines

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Implementation

This guideline will be discussed in existing program of education and included in professional development sessions. It will be available electronically via the ACT Health intranet Policy and Clinical Guidance Register.

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Related Policies, Procedures, Guidelines and Legislation

ProceduresCritical Bleeding /Massive Transfusion

Guidelines Obstetric Emergencies

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References

1. Royal College of Obstetricians and Gynaecologists. Green–top Guideline No. 27. Placenta praevia, placenta praevia accreta and vasa praevia diagnosis and management. London: UK 2011. https://www.rcog.org.uk/globalassets/documents/guidelines/gtg_27.pdf

2. National Institute for Health and Care Excellence (NICE) Guideline. Caesarean section- Clinical Guideline. Manchester UK: NICE Guidelines: 2011. nice.org.uk/guidance/cg132

3. King Edward Memorial Hospital. Placenta Accreta. Perth:WA. 2014. Available from http://www.kemh.health.wa.gov.au/development/manuals/O&G_guidelines/sectionb/2/b2.22.pdf

4. Royal Australian and New Zealand College of Obstetricians and Gynaecologists. College Statement: C-Obs 20. Placenta Accreta. Melbourne, Australia: RANZCOG; 2005.

5. Eller AG, Porter TF, Soisson P, Silver RM. Optimal management strategies for placenta accreta. BJOG 2009;116:648–54.

6. Faranesh, Rita MD, Shabtai, Romano MD, Eliezer, Shalev MD, Raed, Salim MD. Suggested Approach for Management of Placenta Percreta Invading the Urinary Bladder Obstet and Gynecol 2007; 110:512-5.

7. Timmermans S, van Hof AC, Duvekott JJ. Conservative management of abnormally invasive placentation. Obstet and Gynecol Surv 2007; 62:529-39.

8. Alfirevic Z, Tang AW, Collins SL, Robson SC and Palacios-Jaraquemada J, on behalf of the Ad-hoc International AIP Expert Group. Pro forma for ultrasound reporting in suspected abnormally invasive placenta (AIP): an international consensus. Ultrasound Obstet Gynecol 2016; 47: 276–278.

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Definition of Terms

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Placenta accreta: Placenta implants totally/partially/focally through the decidua basalisVilli attached to myometrium

Placenta increta: Villi invade the myometrium

Placenta percreta: Villi fully penetrate the myometriumMay breach the serosa and invade surrounding structures

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Search Terms

Placenta accrete, Placenta increta, Placenta percreta, Morbidly adherent placenta, Adherent placenta, Placenta praevia

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Disclaimer: This document has been developed by Health Directorate, Canberra Hospital and Health Services specifically for its own use. Use of this document and any reliance on the information contained therein by any third party is at his or her own risk and Health Directorate assumes no responsibility whatsoever.

(to be completed by the HCID Policy Team)Date Amended Section Amended Approved By29 December 2016 Whole document ED/CHHSPC Chair

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