Antepartum Haemorrhage Flashcards
definition of Placenta Praevia
placenta developing within the lower uterine segment with a close distance between the lower placental edge and internal os of the cervix
what is considered a low lying placenta
placental edge within 20 mm of internal os
what is considered a normal placenta position
placental edge stary more than 20 mm away from the internal os
what is the pathophysiology of placenta praevia
the placenta develops from discoid trophoblast, the position of placenta depends on the implantation of discoid trophoblast.
in normal pregnancy, the placenta usually migrate away from the internal os, but sometimes this does not occur due to mal-implantation of the discoid trophoblast being lower than usual
how common is placenta praevia
5-28% of pregnancy in 2nd trimester
Risk factor for placenta praevia
advanced maternal age
smoker
artificial reproductive method
prev C/S - inc risk of implantation of discoid trophoblast on the C/S scar
what is the self-made story that reminds me of the risk factors for placenta praevia
An older woman who smokes has a kid with her 3rd husband after previous C/S through IVF.
what are the investigations for placenta praevia
1) foetal anomaly scan at 20 wks - part of the normal USS scan –> if low lying/placenta praevia –> F/U USS + TVS scan at week 32
what does short cervical length inc risk of?
inc risk of emergency C/S and massive haemorrhage at C/S
what are the symptoms of placenta praevia
painless PV bleed that has bright red blood - still oxygenated
what are some management of placenta praevia
advise contacting pregnancy service if contraction starts, bleeding
steroid for baby between 34 and 35 weeks
C/S for any Type 3 or more severe placenta praevia
- vaginal delivery can be attempted but only if marginal/minor praevia
in what conditions will you want to deliver a baby before 37 weeks with placenta praevia
if foetal contractions can not be suppressed
if severe bleeding
if IUGR
if IUD
what is type 1 placenta praevia
placental edge within 20mm of the internal os
what is type 2 placenta praevia
marginal - when the placental edge is very close to internal os but still not cross the internal os
what is type 3 placenta praevia
partial - when parts of the placenta cross/ in the middle of the internal os
what is type 4 placenta praevia
complete - when the internal os is in the middle of the placenta
what is placental abruption
premature seperation of normal sited placenta from uterus
what is the potential aetiology of placental abruption
acute inflammation + chronic vascular dysfunction
inflammation process mediate by cytokines (produces matrix metalloproteinese) which casues destruction of extra-cellular matrix & disruption of cell-cell membrane - ie abruption
blood then tracks down the uterus between the membranes & uterine wall–> further seperation
how can planetal abruption cause PPH
if degree of bleeding is large - large pressure generated in the uterus - blood extend into the myometrium - rupture internally & so blood can affect contraction - PPH
what are the RF/causes of placental abruption
○ Folic acid deficiency –> essential for development of placenta vascular bed
○ Cocaine –> can cause vasoconstriction and disrupt placenta adherence
○ Smoking
○ PIH/PET –> Pregnancy induced hypertension/Pre-eclampsia toxaemia
○ Thrombophilia - inc inflammatory makers?
○ Premature rupture of membranes –> presence of inflammation + infection
○ Multiple pregnancy –> sudden uterus decompression after delivery of first twin
○ Trauma
Recurrence
symptoms of placental abruption
PV bleed constant abdo pain utrine tenderness & woody sensation shock symptoms maternally DIC - bleeding from drip site/skin bruising
investigation for placental abruption
Bloods - FBC, U&es, LFT, G&S (X-match 4-6 units of blood)
Check for HELLP Syndrome
Coag, prothrombin time/activated partial thromboplastin time
fibrinogen level (pregnanct assoicated with hyperfibrinogenaemia & so even modestly dec fibrinogen may show severe coagulopathy – < 200 = severe abruption
Kleihauer- Bettle Test - to detect foeta blood cells in maternal circulation (also helps to correctly dose Anti-D)
USS - to assess blood inuterus or not
mx of placental abruption
if near term + foetus stable - induction by ARM & syntocinon infusion for vaginal delivery
IF FOETAL COMPROMISE - C/S
how do you screen for placenta abruption
uterine artery doppler - vascualr dysfunction leads to reduced invasion of cytotrophoblast & is assoicated with inc risk of placenta abruption
definition of placenta accreta
abnormally invastive placentation that can be categorised by depth
what layer of invasion does placenta accreta involve?
choriic villi attach to the myometrium in the abscence of decidua
what layer of invasion does placenta increta involve?
deepper into the myometrium but not extend to the outmost laters of uterus
what layer of invasion does placenta percreta involve?
through the myometrium up to the serosa
RF for placenta accreta
placenta praevia - implantation problem
prev C/S - decidua basails, a layer that prevents the invasion of trophoblasts cell penetrate deeper into the myometrium - can be damaged due to prev C/S
Ix for placenta accreta
USS
MRI - to help with the depth of invasion and lateral extension of myometrial invasion
what would make you be suspous of placenta accreta
previous C/s + anterior placenta praevia
Mx of placenta accreta
elective admisison from 34 wks + antenal corticosteriods at wk 34 + C/S
what is the risk of C/S hysterectomy if a woman has placenta praevia & prev C/S
27/100
definiton of vasa praevia
when the foetal vessels (not umbilical cord) crossing the internal os through the free placental membrane
what are the different types of vasa praevia
type 1/velamentous - occurs secondary to celamenotus (veli-like) cord insertion - 90%
type 2/succenturiate - occurs when foetal vessels connect lobes of placenta - 10%
what are the RF for vasa praevia
IVF - not naturally implanted & so can implant wrongly
placenta praevia/low-lying placenta
how is vasa praevia diagnosed
detected intrapartum during vaginal exam to fidn the cord to be in the membrane
USS - diagnosed in 2nd trimester - 20% resolve prior to delivery
Mx of vasa praevia?
prophylactic admission nfrom 30-32 wks + corticosteriods from wk 32 + elevative C/S at 34-36 weeks
what is uterine rupture
full thickness loss of the uterine wall and visceral peritoneum
in what circumstance would uterine rpture most likely to occur
during 2nd stage of labour + prev C/S/ prev abdominal surgery
what are the risk factors of uterine rupture
1) prev C/s
2) IOL
3) AOL
4) hyperstimulation
5) inc parity
6) malpresentation - eg breech
7) abnor uterus - eg biconcave
8) macrosomia
9) trauma/RTA
sign and symptoms of uterine rupture
1) can have no signs and symptoms at all - mother can compensate
2) pain between contraction
3) RFM esp during 2nd stage of pregnancy
4) haematuria & blood stain liqour
5) CTG abnor
mx of uterine rupture
stabilisation of mother and emergency C/S
what is placenta accreta
placenta moribidly attached to the uterine wall to an inc degree
degree dependent conditions - accreta, increta, percreta
what is the highest rate of complication for placenta accreta
the retained placenta which might require surgical management
higher risk of PPH
aslo assocaite with per-term labour
management of placenta accreta
elective C-section from 34 weeks + antenatal steriods
hysterectomy is highly likely
which layer of muscle is placenta accreta attach to
directly to the myometrium in the absence of decidua
which layer of muscle is placenta increta attach to
placental villi invade deeper into the myometrium, but do not extend to the outermost layers of the uterus.
which layer of muscle is placenta percreta attach to
chorionic villi penetrate through the myometrium up to the serosa.
ix for placenta accreta
Antenatal diagnosis
Prev C/S + anterior placenta previa suspicious
Imaging
USS
MRI; helps with depth of invasion and lateral extension of myometrial invasion
Diagnostic value of both have been found to be similar
what is vasa previa
fetal vessels crossing the internal cervical os through the free placental membranes
vasa praevia is likely to rupture during active labour or iatrogenically with artificial rupture of membranes
Can lead to fetal haemorrhage, exsanguinationand death
what are the different types of vasa previa
type 1
occurs secondary to a velamentous cord insertion (90% cases)
type 2
occurs when fetal vessels connect lobes of a placenta, for example when a succenturiate lobe is present. (10% cases).
risk factor for vasa previa
IVF
how do you diagnose vasa previa
occasionally detected intrapartum during vaginal examination when vessels are felt in the membrane
USS
Vasa praevia diagnosed in the second trimester resolves in approximately 20% of patients prior to delivery, therefore a repeat scan at 32 weeks is warranted.
management of vasa previa
prophylactic hospitalisation from 30–32 weeks should be considered
Elective delivery via caesarean at 34–36 weeks with a course of antenatal steroids from 32 weeks is reasonable in an asymptomatic patient.
If there is bleeding from a known or suspected vasa praevia, especially with suspected fetal compromise, delivery should be immediate and usually by caesarean section category 1
