Placental issues Flashcards
(39 cards)
1
Q
Describe the types of cord insertion (6 types). For each
-Definition
-Incidence
-Risk factors
A
- Velamentous
- cord vessels are separate before insertion
-Incidence 1% - Marginal cord insertion
- cord inserts in or near the margin of the placenta
-7-9%.
-Increased in twin pregnancies. PTL, IUGR, Fetal distress - Succenturiate
- placenta has 1 or more smaller lobe with exposed vessels running between the two
-Incidence - 5%
-Risk factors - Advanced maternal age, IVF, fibroids, Vasa praevia - Bilobate - placenta is bilobed with no exposed vessels between the two lobes. Lobes are roughly the same size.
Incidence - 2-8%
Risks - increase in abruption, polyhydramnios, retained placenta - Circummarginate
-Extrachorial, annular shape with raised edges composed of a double fold or the chorion. Smaller basal plate.
-PPROM, PTB, Placental insufficiency - Circumvallate
-Extrachorional placenta similar to the circummarginate except the transition to the membranous to villous chorion is flat.
2
Q
Discuss fetomaternal haemorrhage
-Definition
-Causes (3)
-Clinical features (5)
-Investigations (3)
A
- Definition
Haemorrhage of fetal cells into maternal circulation - Causes
-Most of the time no cause is found
-Abruption
-Trauma - Clinical features
-Nil
-APH
-Reduced FM
-Symptoms of transfusion reaction in mother is ABO incompatibility
-IUFD - Investigations
-Kleihauer-Bekte test
-MCA PSV >1.3 MoM = moderate anaemia, >1.5 MoM = severe anaemia
-Cord blood haemoglobin (Cordocentesis)
3
Q
Discuss limitations of the kleihauer bekte test.
1. With the test
2. With the results
A
- Limitations with the test
-Manual counting technique
-Technically challenging
-Interobserver variation
-Variable staining which impacts cell counting - Limitations with results
-Is based on an assumption of maternal blood volume so over estimates in small women and under estimates in large women
-Lifespan of fetal RBC are reduced in maternal circulation with ABO incompatibility
-Only 4% of abruptions have +ve kleihauer
-FMH doesn’t equal abruption and vise versa
4
Q
Discuss unexplained APH
-Risks (6)
-Management
A
- Risks
-PTB OR 3.0
-Still birth OR 2.10
-Fetal anomalies OR 1.42
-NICU admission
-Hyperbilirubinemia
-Lower BW - Management
-If spotting only and placenta praevia excluded can be discharged home
-If anything heavier admit for observation at least until stopped
5
Q
Discuss Vasa praevia
-Definition (2)
-Classification (2)
-Risk factors (4)
-Incidence (1)
A
- Definition
-Passage of fetal vessels within free placental membranes within 2 cm of the internal cervical os
-Vessels are not protected by placental tissue or Wharton’s jelly - Classification
Type I - vessel is connected to velamentous umbilical cord
Type II - vessel connects the placenta with a succenturiate or accessory lobe - Risk factors
-Placenta praevia - OR 22
-Bilobed/Succenturiate lobe OR 22
-Velamentous cord insertion - occurs in 2%
-ART OR 8
-LLP in the third trimester - Incidence
-1:2500
6
Q
Discuss diagnosis of vasa praevia
-Screening (5)
-USS features (4)
-Confirmation (2)
A
- Screening
-No evidence to support universal screening
-RANZCOG supports universal screening of cord insertion at mid trimester scan but not routine TVUSS for vasa praevia
-Targeted screening in those with risk factors for vasa praevia with TAUSS then TVUSS if concerning features (RCOG doesn’t recommend - insufficient evidence)
-Need to use colour doppler and TVUSS to confirm. (High sens and spec 100% & 99.8%. Most accurate method RANZCOG)
-Best done 18-20 weeks with confirmation at 30-32 weeks
-If risk factors then consider TVUSS on midtrimester scan - USS features
-Aberrant liner or tubular echolucent structure
-Blood flow within these structures on doppler
-Umbilical artery/venous wave form on pulse doppler
-Aberrant vessel or vessels located within 2cm of internal os attached to the inner perimeter of the fetal membranes - Confirmation
-If seen in 18-20 weeks scan repeat scan at 30-32 weeks
-Resolution occurs in 20%
7
Q
Discuss antenatal management of vasa praevia (11)
A
- Tertiary referral
- Prophylactic hospitalisation from 30-32 weeks (RANZCOG)
- If considering outpatient management a long closed cervix and negative FFN would be reassuring but not evidence based
- Role of cervical length and cerclage is unknown
- Steroids at 32 weeks as precaution for rapid delivery
- Aim delivery 34-36 weeks. Never after 37 weeks
- Immediate CS if PPROM or labour or suspected bleeding from fetal vessels. Have O neg blood available
- If SROM with bleeding and fetal distress consider vasa praevia and deliver. Don’t await Dx
- Aim delivery in a hospital with appropriate neonatal resus ability
- Delivery is by CS with mapping of fetal vessels to avoid laceration
- Send placenta for histo in event of still birth or neonatal death
8
Q
Discuss possible clinical manifestations of vasa praevia (3)
A
- Dx on USS
- Palpation of pulsating fetal vessels at internal os on VE
- Dark red vaginal bleeding and acute fetal compromise after SROM or ARM
9
Q
Discuss management of vasa praevia when undiagnosed on USS (4)
A
- Cat 1 section. Do not wait for diagnosis
- Inform paeds
- Neonatal resus probable
- Neonatal blood transfusion with O neg blood likely
10
Q
What is the fetal prognosis with vasa praevia
-Overall mortality
-Mortality when dx by USS antenatally
-Mortality if undiagnosed antenatally
A
- Overall mortality - 36%
- Mortality with antenatal dx - 3%
- Mortality without antenatal dx 66%
11
Q
Discuss placenta praevia
-Incidence (4)
-Classification (3)
-Risk factors (8)
A
- Incidence
-1:5 at 24 weeks
-1:200 at term
-1:100 if previous CS - RR4.5
-3:100 if 3 previous CS - RR 6.5 - Classification
-Can be assessed if >16 weeks
-Placenta praevia = covering internal os
-Low lying placenta = within 2 cm of internal os - Risk factors
-Smoking OR 1.4
-IVF pregnancy OR 3.7
-Previous D&C
-Previous CS esp if done pre labour or less than 12 months ago. Dose response
-Previous placenta praevia - risk recurrence 4-8%
-Multiparity
-AMA
-Multiple pregnancy
12
Q
Discuss placenta praevia
-Who and when should there be screening (4)
-What are the chances of resolution (2)
-What factors make resolution less likely (3)
-What is the role of cervical length (2)
A
- Who and when should there be screening
-All women should have placental location documented at routine anatomy scan
-Screen if APH
-Repeat scan at 32 weeks as 90% will have resolved
-Repeat scan at 36 weeks as another 50% will have resolved - Factors which make resolution / migration less likely
-Previous CS
-Posterior placenta
-If placenta >2.5cm over internal os - Role of cervical length
-Short cervix (<30mm) <34/40 is predictive of increased risk of haemorrhage and PTB.
-Impact of a cerclage is unknown and not recommended
13
Q
Discuss placenta praevia
-Maternal risks (4)
-Fetal risks (5)
A
- Maternal risks
-PPH
-Hysterectomy
-DIC
-AKI - Fetal risks
-Prematurity and associated perinatal morbidity
-Cord prolapse from malpresentation
-IUGR
-Anaemia from exsanguination if placenta incised during CS
-Fetal mortality - 8:100
14
Q
Discuss presentation of placenta praevia
-Bleeding (6)
-Pain (2)
-Examination (2)
A
- Bleeding
-30% bleed before 30/40
-30% bleed 30-36/40
-30% bleed >36/40
-10% bleed in labour
-Precipitated by shearing forces on placental vasculature - sexual intercourse.
-Often unprovoked - Pain
-Bleeding is usually painless
-Can be associated with contractions either prior to onset of bleeding or post bleeding from uterine irritability - Examination
-Anyone with bleeding and high presenting part need to rule out placenta praevia
-Don’t do a VE
15
Q
Discuss antenatal management of placenta praevia (9)
A
- Optimise Hb
- Ensure up to date G&H with blood put aside if difficult crossmatch
- Advise to avoid sexual intercourse or travel far from medical assistance
- Advise to present if contractions, bleeding, pain
- Consider steroids (RCOG single dose 34-35+6)
- Serial growth scans if APH
- TEDS and mobilisation for thromboprophylaxis
- Individualise location of care based on pregnancy circumstances and social circumstance
- Consent and advise around risk of hysterectomy (2% if praevia, 10% if praevia + prev CS)
- If presenting in PTL with PVB but stable tocolytics can be considered
16
Q
Discuss delivery options for placenta praevia
-Risk factors for emergency caesarian section (4)
-Location (4)
-Mode of delivery (2)
-Timing of delivery (3)
-Preparation of blood products (4)
A
- Risk factors for emergency caesarian section
-Sentinel bleed <29 weeks
-APH esp. if multiple
-Previous CS
-Shortened cervix <3.1cm - Location
-Unit with blood transfusion service and access to critical care
-If CS then should have facilities
-If preterm then should have NICU who can manage that gestation - Mode of delivery
-CS if complete praevia or if heavy or continued bleeding in labour or if maternal or fetal compromise from bleeding
-In LLP VB more likely if: head is engaged and beyond leading edge of placenta, placental edge is <1cm thick. - Timing
-No bleeding 36-37 weeks
-Episode of bleeding 34-36+6 weeks
-Profuse bleeding at any point - Blood product preparation
-2 units id no APH and trialling VB
-4 units if no APH and CS
-6-10 units + FFP if major APH
-Consider cell salvage
17
Q
Discuss delivery of woman with placenta praevia
-Surgical approach (5)
-Methods to manage haemorrhage
A
- Surgical approach
-Consider vertical skin and uterine incision if baby in transverse lie
-Use USS pre and intraoperatively to map placenta boarders
-If placenta is transected clamp umbilical cord immediately
-Have instruments available for hysterectomy
-Have senior obstetrician onsite or scrubbed - Haemostatic techniques
-Close uterus - best way to stop placental bed bleeding unless profuse
-TXA and ecbolics
-Placental bed sutures - 2 x2cm sutures into myometrium
-Uterine artery ligation - dissect bladder down to avoid ureters. Use 1.0 vicryl on blunt needle to ligate. Place suture high and low on either side
-Bakri balloon
-B-Lynch suture- not designed for praevia but can be used in conjunction with balloon. Avoid too tight can cause blanching and necrosis
-Uterine artery embolisation
-Hysterectomy - definitive management
18
Q
Discuss placental abruption
-Definition of abruption (1)
-Incidence (2)
-Risk of recurrence (2)
A
- Definition
-Separation of the placenta from the uterus anytime from viability to second stage of labour - Incidence
-1% of all pregnancies
-50% of cases occur intrapartum - Risk of recurrence
-5% after one abruption
-20-25% after two abruptions
19
Q
Discuss definitions of APH
-Overall definition
-Incidence
-Minor haemorrhage
-Major haemorrhage
-Massive Haemorrhage
A
- Overall definition
-Bleeding from genital tract from 20+0 till birth. No specific amount - Incidence
-3-5% of pregnancies
-20% of very preterm babies born in association with APH - Minor haemorrhage
- < 50mL that has settled - Major haemorrhage
-Blood loss of 50-1000mL with no signs of clinical shock - Massive haemorrhage
-Blood loss >1000mL or signs of clinical shock
20
Q
Discus risk factors of placental abruption
-Incidence of abruption in low risk pregnancies (1)
-Pre-existing factors (4)
-Pregnancy factors (9)
A
- 70% of abruptions occur in low risk pregnancies
- Pre-existing risk factors
-Previous placental abruption OR 7.8 / 5%
-Advance maternal age
-High Parity
-Thrombophillias - FV Leiden and prothrombin gene
-Low maternal BMI - Current pregnancy factors
-IVF
-Bleeding in first trimester esp with haematoma identified
-Trauma - MVA, Domestic violence
-Notching on uterine artery
-PET/HTN
-PPROM, Chorioamnionitis
-SROM with polyhydramnios or multiple pregnancy
-Substance abuse - smoking, cocaine, amphetamines
-ECV
-Non vertex presentation
21
Q
Discuss work up of placental abruption
-Presenting symptoms (5)
-Examination findings (3)
-Investigations (5)
A
- Presenting symptoms
-Abdominal pain - intermittent vs continuous vs absent
-PVB
-Persistent uterine activity or increased tone
-PTL
-Blood stained liquor - Examination findings
-Tender uterus with woody feel and increased tone
-Speculum for source of bleeding and cervical dilation
-Avoid digital exam until praevia excluded - Investigations
-Clinical diagnosis
-CBC and coags
-Kleihauer - Very poor sensitivity and specificity - don’t do as a diagnostic test only use for anti-D guide
-USS - limited diagnostic value. Fails to detect 75% of cases but if reports abruption then there is likely to be an abruption!
-CTG for fetal wellbeing once mother stable
22
Q
Discuss management of placental abruption
-If maternal or fetal compromise (5 points)
A
- ABCD
- Resuscitate mother as first priority
- If fetus is alive aim for delivery
-Instrumental if fully dilated
-CS if not fully dilated
-May need to be under GA if in DIC - If fetus is dead aim for vaginal delivery
-Replace blood and coagulation products - Monitor mother for DIC, AKI, acute anaemia
23
Q
Discuss management of placental abruption
-If NO maternal or fetal compromise in labour (3)
-If NO maternal or fetal compromise not in labour (9)
A
- If in labour
If in labour allow to proceed with continual fetal monitoring
Anticipate PPH as APH risk factor - active third stage
Thromboprophylaxis PN - If not in labour
-Admit and observe 24-48 hrs after bleeding has settled
-Steroids if < 34+6
-Tocolysis is contraindicated but can be considered by senior obstetrician for transfer or steroid completion
-Offer IOL if term.
-Growth scans
-Offer IOL at 37-38 weeks if recurrent bleeding or IUGR otherwise no need for IOL
-Manage anemia
-Give anti-D if required
24
Q
Discuss complications of placental abruption
-Maternal (5)
-Fetal (4)
A
- Maternal
-Anaemia
-Infection
-Hypovolemic shock
-DIC
-PPH - Fetal
-Fetal hypoxia
-SGA and IUGR
-Prematurity
-Still birth
25
Discuss DIC
-Incidence in placental abruption (1)
-Pathophysiology (3)
-Investigations (4)
-Management
1. Incidence - 35% in placental abruption
2. Pathophysiology
-Damaged placental tissue releases thromboplastin triggering extrinsic pathway
-Consumption of clotting factors, platelets and fibrinogen
-Activation of fibrinolytic system resulting in anticoagulation and uncontrolled bleeding
-Micro vascular clot formation can cause end organ damage
3. Investigations
-APTT, PT, Fibrinogen
-Platelets
4. Management
-Liaise with senior haematologist
-4 units of FFP and 10 of cryo while waiting for coag studies if relentless bleeding
-Platelets if <50
26
Discuss placenta accreta spectrum
-Pathophysiology of normal placentation (1)
-Pathophysiology of abnormal placentation (3)
1. Pathophysiology of normal placentation
-Chorionic villi attach to the stratum basalis of the endometrium and are separated from the decidua by the nitabuch line.
2. Pathophysiology of abnormal placentation
-The Nitabuch line prevents excessive penetration of the decidua by trophoblasts
-In accreta spectrum the layer is absent which stops separation and allows for invasion
-Absence also impacts how the spiral arteries and intervillous spaces develop
27
What are the types of abnormal placentation and what percentage of abnormal placentation to they make up (3)
1. Placenta accreta
- 80 % of all abnormal placentation
-Chorionic villi attach directly to the uterine myometrium
2. Placenta increta
-15% of all abnormal placentation
-Chorionic villi invade the myometrium
3. Placenta percreta
-5% of all abnormal placentation
-Chorionic villi invade through the myometrium and serosa
-May invade adjacent organs that are below the peritoneal reflection (Bowel and bladder)
28
Discuss accreta spectrum disorder
-Incidence (2)
-Risk factors (11)
1. Incidence
-Rising as increase in CS rates
-1:2000
2. Risk factors
-Previous accreta - recurrence rate15-30%
-Scar pregnancy diagnosed in first trimester
-Previous CS: 1 CS OR 2.0; 2 CS OR 9-18; 3 CS OR 56*
-Placenta praevia 3% chance*
-Placenta praevia + CS: 3% if 1 CS, 11% if 2 CS, 40% if 3 CS
-Previous postpartum endometritis
-Previous uterine surgery OR3.4 - MROP, myomectomy, curettage, endometrial ablation
-Short CS pregnancy interval
-Increase in maternal age >35yrs*
-ART
-Abnormally shaped uterus
-Multiparity*
29
Discuss placenta accreta spectrum diagnosis
-Value of antenatal diagnosis (2)
-Who should be screened (1)
-USS utility (2) and findings (8)
-MRI utility (4) and findings (5)
1. Value of antenatal diagnosis
-50% are not diagnosed antenatally
-Antenatal diagnosis and planning has been shown to reduce morbidity and mortality
2. Who should be screened
-Women with previous CS and low lying placenta or placenta praevia
2. USS utility
-Sensitivity 50-70% and specificity 97%. Relies on high clinical suspicion
-Best time to scan 24-26 weeks. Accuracy declines across 3rd trimester
3. USS findings
-Loss of hypoechoic plane in myometrium underneath the placental bed
-Prescence of numerous lacunae that are large and irregular and contain turbulent flow - "moth eaten '
-Loss or interruption of the bright bladder wall
-Thinning of the myometrium overlying the placenta
-Deviation of the uterine serosa away from the expected plane caused by bulge of placental tissue
-Subplacental hypervascularity
-Bridging vessels across myometrium
-Placental lacunae with feeder vessels
4. MRI utility
-No better than USS but used both together is helpful if placenta posterior
-83% sensitivity, 83% specific
-Scan at 24-28 weeks
-Scan be used to determine extent of invasion esp on posterior placentas
5. Findings
-Abnormal uterine bulge
-Dark intraplacental bands on T2 weighted
-Heterogenous signal intensity
-Disorganised vasculature of the placenta
-Disruption of the utero-placental sone
30
Discuss risks of placenta accreta spectrum for mothers (6)
1. Haemorrhage - 50% have PPH
-Medium blood loss 2-8L
-Massive transfusion >10 units in 40%
2. Hysterectomy
3. Bladder injury - 17%
4. Ureteric injury - 10-15%
5. Mortality - 6%
6. Uterine rupture at any time in pregnancy esp if percreta
31
Discuss antenatal management of placenta accreta spectrum
-Who should be involved (7)
-Where should delivery occur (4)
-Timing of delivery (2)
-Bleeding considerations (3)
-Surgical planning (3)
1. Who should be involved
-MDT input from obs, gynae, urologist, radiologist, haematologist, anaesthetist, vascular
2. Location of delivery
Plan delivery at location with high volume transfusion capability, surgical specialties, ICU, NICU
3. Timing of delivery
-Aim 35-36+6
-If APH or risks factors for preterm delivery consider after 34/40
4. Bleeding considerations
-Valid G&H
-Optimise Hb
-Consider cell salvage
5. Surgical planning
-Consider MRI for surgical planning
-Anaesthetic review
-Counsel woman regarding surgical risks and options for surgery
32
Discuss delivery for placenta accreta spectrum
-Bleeding considerations (4)
-Anaesthetic type (2)
-Positioning (1)
-Incision type (3)
-Ecbolics (2)
-Urological considerations (3)
-IR considerations (4)
1. Bleeding considerations
-Alert blood bank
-Cross match 4 units initially
-Alert haematologist and have available
-Consider access to cell saver
2. Anaesthetic type
-Both regional and GA
-Choice to be made in conjunction with woman
3. Positioning
-Lithotomy to allow access from between leg and to access vagina and do cystoscopy if required
4. Incision type
-Midline on skin
-USS to map placenta and cut away from this
-Consider fundal or high transverse incision
5. Ecbolics
-Don't give if planning to leave placenta insitu
-Can use if planning to take placenta out
6. Urological considerations
-Urological stents no routinely required but if bladder invasion suspected can use
-Consider early cystotomy at site of placental invasion and bladder repair instead of dissection
7. IR considerations
-Preoperative balloon placement is controversial. No good RCT evidence. Not routinely recommended
-Consider balloon placement in those where hysterectomy is planned
-Uterine artery embolisation in women who are attempting to preserve the uterus can be considered if PPH
-Balloon complications include internal iliac artery dissection
33
Discuss surgical options for managing placenta accreta spectrum
-Considerations for surgical options (6)
1. Things to consider regarding surgical options
-Position of placenta
-Depth of invasion
-Parametrial extension
-Visual inspection at the time
-Presenting clinical symptoms
-Woman's preferences
34
Discuss surgical options for managing placenta accreta spectrum
-Attempted delivery of placenta (5)
-Consider if depth and surface area of placenta is limited
-High risk for significant bleeding
-Manage as placenta praevia with ecbolics, placental bed sutures, b-lynch, uterine artery ligation and Bakri balloon
-May require partial myomectomy at placental site and then repair of uterus
-Early recourse to hysterectomy if bleeding ongoing
35
Discuss surgical options for managing placenta accreta spectrum: Leave placenta insitu
-Considerations (2)
-Surgical approach (3)
-Possible outcomes (3)
-Risks of retained placenta (9)
-Clinical follow-up (4)
1. Considerations
-Consider if undiagnosed and in location without appropriate services to enable transfer or if hysterectomy considered inappropriate to team or woman
-Consider in appropriately counselled women who will be able to commit to long term FU
2. Surgical approach
-Deliver baby via uterine incision well away from placenta.
-Trim and tie cord close to placental insertion site.
-Do not give ecbolics
3. Possible outcomes
-40% need hysterectomy for uncontrolled bleeding
-Resorption occurs over 14 weeks
-Some pass the placenta
4. Risk of leaving placenta
-40% severe morbidity
-Chronic bleeding
-Sepsis
-Peritonitis
-Uterine necrosis
-Fistula
-Injury to adjacent organs, AKI, pulmonary oedema
-DVT/PE
5. Clinical follow-up
-Regular clinical review
-Serial HCG
-No evidence methotrexate as adjuvant therapy
-Prophylactic antibiotics
-Repeat placenta accreta up to 30%. Good fertility rates
36
Discuss surgical options for managing placenta accreta spectrum
-Planned CS hysterectomy (4 points)
1. Best practice as reduced risk of massive haemorrhage - contraversial. Observational studies suggest less blood loss with conservative measures
2. Delivery baby through uterine incision distant to placenta
3. Close uterus then undertake hysterectomy enbloc
4. Cystomoy is OK
37
What is the triple P procedure for managing placenta accreta spectrum
1. Perioperative location of placenta and delivery fetus from incision above the upper boarder
2. Pelvic devascularisation with IR placed occlusion balloons in both illiac arteries
3. Placental non-separation with myomectomy excision and reconstruction of uterine wall
38
Discuss antepartum haemorrhage
-Definition (1)
-Incidence (2)
-Most important causes (2)
1. Definition
-Any bleeding from genital tract from 24/40 until delivery
2. Incidence
-Complicates 3-5% of pregnancies
-Leading cause of maternal and fetal mortality
3. Most important causes
-Abruption
-Praevia
39
Discuss complications of APH
-Maternal (9)
-Fetal (5)
1. Maternal complications
-Anaemia
-Infection
-Maternal shock
-Renal tubular necrosis
-Consumptive coagulopathy
-PPH
-Psychological sequalae
-Complications of blood transfusion
2. Fetal complications
-Fetal hypoxia
-SGA or IUGR
-Prematurity
-Mortality
-NICU admission and hyperbilirubinemia
