Placenta Praevia and Abnormally Invasive Placenta (AIP)



Canberra Hospital and Health ServicesClinical Guideline Placenta Praevia and Abnormally Invasive Placenta (AIP)Contents TOC \h \z \t "Heading 1,1" Contents PAGEREF _Toc494443817 \h 1Guideline Statement PAGEREF _Toc494443818 \h 2Alert PAGEREF _Toc494443819 \h 2Scope PAGEREF _Toc494443820 \h 2Section 1 – Background PAGEREF _Toc494443821 \h 2Section 2 – Antenatal care of the woman with suspected Placenta Praevia or Abnormally Invasive Placenta PAGEREF _Toc494443822 \h 3Section 3 – Pre-operative management of AIP PAGEREF _Toc494443823 \h 5Section 4 – Emergency surgery PAGEREF _Toc494443824 \h 6Section 5 – Operative day PAGEREF _Toc494443825 \h 7Implementation PAGEREF _Toc494443826 \h 8Related Policies, Procedures, Guidelines and Legislation PAGEREF _Toc494443827 \h 8References PAGEREF _Toc494443828 \h 8Definition of Terms PAGEREF _Toc494443829 \h 9Search Terms PAGEREF _Toc494443830 \h 9Guideline StatementThis 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.AlertWomen with morbidly adherent/invasive placentation are potentially at very high risk of serious morbidity and therefore a high level of consultant involvement is required.Back to Table of ContentsScopeThis document applies to Canberra Hospital Health Services (CHHS) staff working within their scope of practice including but not limited to:Medical OfficersRegistered Nurses and MidwivesStudents working under supervisionsonogaphers/interventional radiologistsBack to Table of ContentsSection 1 – BackgroundPlacenta 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). 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 basalisVilli attached to myometriumPlacenta increta Villi invade the myometriumPlacenta percreta Villi fully penetrate the myometriumMay breach the serosa and invade surrounding structuresRisk Factors Previous uterine surgery – Caesarean section, uterine curettage, myomectomyPrevious retained placentaAdvanced maternal ageBack to Table of ContentsSection 2 – Antenatal care of the woman with suspected Placenta Praevia or Abnormally Invasive PlacentaUltrasound 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 sectionAnomaly 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 gestationIn 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 birthFor women who have previously had a caesarean section, it is important to rule out AIP especially when there is anterior placenta praeviaIn cases of symptomatic women, imaging should be performed as appropriateDiagnosis 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 CareThe 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 deliveryFor 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) ObstetricianA further scan with a senior member of the FMU team present should be considered to assist with surgical planningOnce 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 madeThe woman’s haemoglobin levels and iron stores should be checked and optimised prior to surgeryAs 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 documentedThe 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 AIPSteroids may be administered as prescribed if requiredThe management plan is to be formulated by the obstetric team in consultation with medical imaging, operating theatres and other teams as neededWomen 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 outcomeSurgical 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 determinedThere 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 anaesthetistBack to Table of ContentsSection 3 – Pre-operative management of AIPElective Surgical Procedure This requires complex multi-disciplinary involvement that relies on excellent communicationObstetricsAn 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 rm 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.UrologyRefer to specialist urologist for flexible cystoscopy and consideration of ureteric stenting and possible involvement with delivery if appropriateAnaesthesiaArrange 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 procedureNeonatal teamDate and time of procedure, to be notified for a NICU bed. Arrange antenatal consultation with Neonatologist if less than 32 weeks gestationVascular SurgeryDate and time of procedure, assistance may be required.Gynaecology OncologistDate and time of procedure, assistance may be required.WomanCounsel the woman and her family about the suspected diagnosisDiscuss the need for operative birth and the timingThe option of prophylactic interventional radiologyThe implications in terms of hysterectomy, massive blood loss, cell salvage and blood transfusionThe 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 hysterectomyImmediate care of her baby after birthConservative 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. Back to Table of Contents Section 4 – Emergency surgeryEmergency 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 rm the 1st and 2nd on-call obstetric consultantsInform the on-call anaesthetic consultantInform the theatre co-ordinator and request appropriate staffNotify NICUInform 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 admissionBack to Table of Contents Section 5 – Operative dayPre-operativeAll 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 preparationThe woman is encouraged with antenatal expression of colostrum with obstetric consultationEnsure pathology collected including blood cross matchingLiaise with urologist for cystoscopy and ureteric stent insertion. If iliac artery balloon placement anticipated, liaise with Interventional radiologistOrder MRI and discuss results with RadiologistDay of SurgeryEnsure urinary catheter has been inserted prior to transfer to Interventional Radiology Department On arrival in Interventional Radiology continuous CTG commencedIf required, iliac artery balloons are placed before transfer to theatreWoman 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 nurseMidwife provides routine intra-operative careDepending 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 ICUWhere 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 wardRepeat pathology as requiredIntraperitoneal drain and IDC out as per surgeons recommendationUreteric stents to be removed as per urologist recommendationRoutine postoperative care and postpartum care will be provided as per the woman’s clinical situationCare should be taken to provide a debrief if required including referral to social workBreastfeeding and expressing are supported as requiredRoutine care is provided for the baby as per relevant GuidelinesBack to Table of ContentsImplementation 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.Back to Table of ContentsRelated Policies, Procedures, Guidelines and LegislationProceduresCritical Bleeding /Massive TransfusionGuidelines Obstetric EmergenciesBack to Table of ContentsReferencesRoyal College of Obstetricians and Gynaecologists. Green–top Guideline No. 27. Placenta praevia, placenta praevia accreta and vasa praevia diagnosis and management. London: UK 2011. National Institute for Health and Care Excellence (NICE) Guideline. Caesarean section- Clinical Guideline. Manchester UK: NICE Guidelines: 2011. .uk/guidance/cg132King Edward Memorial Hospital. Placenta Accreta. Perth:WA. 2014. Available from Australian and New Zealand College of Obstetricians and Gynaecologists. College Statement: C-Obs 20. Placenta Accreta. Melbourne, Australia: RANZCOG; 2005.Eller AG, Porter TF, Soisson P, Silver RM. Optimal management strategies for placenta accreta. BJOG 2009;116:648–54.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.Timmermans S, van Hof AC, Duvekott JJ. Conservative management of abnormally invasive placentation. Obstet and Gynecol Surv 2007; 62:529-39.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.Back to Table of ContentsDefinition of Terms Placenta accreta: Placenta implants totally/partially/focally through the decidua basalisVilli attached to myometriumPlacenta increta: Villi invade the myometriumPlacenta percreta: Villi fully penetrate the myometriumMay breach the serosa and invade surrounding structuresBack to Table of ContentsSearch Terms Placenta accrete, Placenta increta, Placenta percreta, Morbidly adherent placenta, Adherent placenta, Placenta praevia Back to Table of ContentsDisclaimer: 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 AmendedSection AmendedApproved By29 December 2016Whole documentED/CHHSPC Chair ................
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