Ha - Obstetrics Flashcards
how is the FBC different in pregnancy
mild anaemia
macrocytosis
neutrophilia
thrombocytopaenia
why do you get a mild anaemia in preg
mainly due to plasma volume rising
red cell mass increases but not as much
why do you get thrombocytopaenia in preg
increased platelet size (immature platelets) due to increased turnover
what blood demands are increased in preg
increased iron req from 1-2mg to 6mg daily absorption
increased folate (200mcg/day extra)
what can iron def casue in preg
IUGR
prematurity
PP haemorhage
is iron excreted in the body?
NO - it is just recycled or not absorbed in the first place if it is not needed
when should folic acid supplements be given in preg
before conception and for the 12+ weeks of gestation
what dose of folic acid is given in preg
400 ug daily
define anaemia in preg (each trimester and PP)
Hb <110 1st trimester
Hb <105 2nd/3rd trimester
Hb < 100 PP
blood film results of iron def anaemia
low Hb
low MCV
low MCH
+ low ferritin
when does platelet count fall in preg
physiologically in 3rd trimester
causes of low platelets in preg
physiological
pre eclampsia
ITP
microangiopathic syndromes
others: BM failure, leukaemia, hypersplenism
if the platelets are severely low in preg, what is the most likely cause
ITP or pre eclampsia
if the platelets are marginally low in preg, what is the most likely cause
physiological
what is the physiological decrease in platelet count in preg %
10%
what is a sufficient platelet level for delivery
> 50x10^9
why does platelet count drop in preg
poorly understood - but dilution + increased consumption
when does platelet count start to rise again PP
2-5 days
what % of pre eclampsia pts have low platelets & how does it relate to disease
50% (proportionate to severity)
when does low platelets resolve in pre eclampsia
after delivery
why does pre eclampsia cause low platelets
increased activation and consumption leading to DIC
Tx of ITP in preg
IV IG or steroids
% of preg ppl with ITP
5% (many have it before preg)
can ITP affect baby
yes - variable though
Mx of ITP in preg
check cord blood then daily baby blood as may fall for 5 days PP
what is seen on blood film of microangiopathic syndromes
low platelets
schistocytes (RBC fragments)
for which MAHA conditions does delivery affect / not affect course
affects pre eclampsia, HELLP syndrome
does not affect TTP or HUS
leading cause of mortality in pregnancy
VTE
blood in preg becomes ____coagulable due to ______ and ____fibrinolytic due to ______
hypercoagulable
- increase in factor 8 and vWF
hypofibrinolytic
- half of protein S and increased PAI-1
why is blood in pregnancy procoagulant (3)
increased thrombin production
increased fibrin cleavage
reduced fibrinolysis
when is VTE risk for preg mothers greatest
1-6 weeks PP
which Ix are done for ?VTE in preg
doppler and VQ
which Ix is not done for ?VTE in preg and why
D-dimer - raised anyway by preg
what factors increase VTE risk for all preg mothers
increased coagulability of blood
reduced venous return
vessel wall is prothrombotic
what variable factors can increase VTE risk for some preg mothers
hyperemesis / dehydration
obesity
pre-eclampsia
PMH thrombosis
age / parity
multiple preg
ovarian hyperstimulation IVF
who is most at risk of VTE in preg (age)
> 40s
how can VTE be prevented in preg
women with risk factors given heparin and TED stockings
mobilise early
maintain hydration
why is LMWH used but not warfarin for VTE in preg
LMWH does not cross placenta
warfarin crosses placenta
when does VTE prophylaxis need to be stopped in preg
for labour or planned delivery esp epidural
what is the rule for anticoag and epidural
wait 24hrs after Tx dose or 12hrs after prophylactic dose to give epidural
what issues does warfarin cause for baby
chondrodysplasia punctata
- abnormal cartilage and bone
- early epiphyses fusion therefore short
- nasal hypoplasia
- asplenia
- deafness
- seizures
when in preg is warfarin teratogenic
1st trimester
what is antiphospholipid syndrome
recurrent miscarriages, VTEs, persistent lupus anticoagulant +/- APL ABs
what is the biggest maternal mortality factor in less developed countries
haemorrhage
what 2 main causes of maternal haemorrhage are there
placenta praevia
placenta accreta
define PP haemorrhage
> 500ml blood loss
what % of preg have >1L blood loss
5
4 causes of PP haemorhage
4Ts
tone - uterine atony
trauma - laceration / rupture
tissue - retained placenta
thrombin - coagulopathy
2 main causes of PP haemorrhage
uterine atony
trauma
what haematological factors can cause PP haemorrahage
dilutional coagulopathy after transfusion
DIC in abruption
amniotic fluid embolism
what do coagulation changes in preg predispose the mother to
DIC - disseminated intravascular coagulation
what precipitates a mother to decompensate into DIC
amniotic fluid embolism
abruptio placentae
retained dead foetus
pre-eclampsia
sepsis
incidence of amniotic fluid embolism
1 in 20-30,000
Sx of amniotic fluid embolism
sudden onset shivers, vomitting, shock, DIC
mortality of amniotic fluid embolism
86%
risk factors for amniotic fluid embolism
> 25 years old
third trimester
misoprostol (labour inducing drug)
what haemaglobinopathies are screened for in babies
alpha thalassaemia
beta thalassaemia
sickle cell
prognosis of alpha and beta thalassaemia
alpha - death in utero
beta - tranfusion dependent
