Placenta Praevia Flashcards
Define placenta praevia
A placenta located wholly or in part into the lower segment, covering the internal os
What is a low-lying placenta
the placental edge is less than 20 mm from the internal os on transabdominal or transvaginal scanning >16 weeks
What is the difference between minor and major grade placenta praevia
Minor Grade 1-2
- Placenta in the lower segment, close to or encroaching on the cervical os
- Mode of delivery must be caesarean IF the placenta is within 2cm of the os, if further then vaginal delivery is possible
Major grade 2-4
- The placenta lies over the cervical os
- Mode of delivery must be a caesarean section - cannot do a VE in these patients due to the risk of bleeding
What are the risk factors for placenta praevia
Previous placenta praevia
Advanced maternal age
Curettage to endometrium e.g. in assisted conception
Increased parity
Previous C-section
Smoking
What are the symptoms of placenta praevia
Painless PV bleeding
Low-lying placenta on 20 week scan
What are the differentials for placenta praevia
Placental abruption
Miscarriage
CIN
ectropion
Trauma
What are the signs of placenta praevia on examination
Obs: hypotension + tachycardia
Abdominal exam: non-tender uterus
Note: Do NOT do VE due to risk of placental rupture
What investigations should be done for placenta praevia
- A-E assessment
- Bloods
- TV USS
Bloods: FBC, G&S, Rh status, X-match, U&Es, coagulation screen, Kleihauer-Betke test, LFTs, alpha-fetoprotein
Other:
TVUSS: confirm placenta praevia and assess cervical cancer
Doppler: screen for placenta accreta
CTG: assess foetal status
What is the management for symptomatic placenta praevia
- A-E exam
- Admit to ward if 34 weeks (but consider VTE risk)
- Stabilise - 2x wide bore cannulas, fluids, antifibrinolytic, CTG
- <34 weeks → steroids, magnesium
- anti-D if Rh negative
Unstable (bleeding uncontrolled, foetal distress) → EMCS
Stable:
<37 weeks grade1/2: vaginal delivery
<37 weeks grade 3/4: C-section
<37 weeks: ELCS at 37 weeks
What is the management for asymptomatic placenta praevia picked up at anomaly scan
Repeat scan at 32 and 36 weeks to assess the position of the placenta (may end up higher due to uterine stretching)
Grade 1/2: vaginal delivery at 36-37 weeks
Grade 3/4: ELCS at 36-37 weeks
Asymptomatic women with PP can remain at home if:
- They live close to the hospital
- Fully aware of the risk to self and foetus
- Have a constant companion
- Have telecommunication and transport
Advise not to have penetrative intercourse
Any sudden gushes of fluid - should come into hospital ASAP
What are the complications or placenta praevia
Pre-term delivery
Requirement for blood transfusion
Postpartum haemorrhage → hypovolaemic shock
Disseminated intravascular coagulation (DIC)
Hysterectomy in severe cases due to invasion of placenta into the endometrium
Increased VTE risk due to prolonged hospital admission
Sudden infant death syndrome (SIDS)
What is the prognosis for placenta praevia
Placenta praevia in early gestation may migrate into a normal position as pregnancy progresses (growth at the upper end of the placenta)
About 85% of placentas that are praevia at 15-20 weeks and 33% at 20-23 weeks will no longer be praevia at the onset of labour
Maternal progress is generally good.
Increased risk of receiving blood transfusion and hysterectomy
Foetal prognosis is good, but may be compromised by excessive bleeding and IUGR
What is placenta accreta
where chorionic villi invade the endometrium and may attach to the myometrium, rather than being restricted within the decidua basalis
What is placenta increta
where the chorionic villi invade into the myometrium
What is placenta percreta
where the chorionic villi invade through the myometrium, attaching to the serosa and sometimes into adjoining tissue (can attach to bladder or bowel sometimes) i.e. all layers
