Placental Abruption

Question 1

What is placental abruption?

Answer 1

When part of the placenta becomes detached from the uterus resulting in bleeding
(Separation occurs between the uterine wall and decidua basalis)

Question 2

What does the outcome depend on?

Answer 2

Amount of blood loss

Degree of separation

Question 3

Can it reoccur in subsequent pregnancies?

Answer 3

Yes 4% (19-24% if twice)

Question 4

What are the distinguishing features?

Answer 4

Shock out of keeping with visible loss
Pain constant, in area of abruption 
Tender, tense uterus - strong muscular layer clamping down to reduce bleeding 
Normal lie and presentation 
Fetal heart absent/distressed
Coagulation problems 
Beware pre-eclampsia, DIC, anuria

Question 5

What risk factors are there?

Answer 5

Abruption in previous pregnancy 
Pre-eclampsia
Smoking
Drug misuse - cocaine, methamphetamine (cause vasoconstriction of vessels and abrupt increase in BP) 
IUGR
PROM
Multiple pregnancy
Increased maternal age >35
Abdominal trauma - car crash, fall, domestic abuse 
Polyhydramnios 
Assisted reproduction 
Intrauterine infection 
Non vertex presentation
Low BMI
Thrombophilias

Question 6

What are the consequences of placental abruption?

Answer 6

Placental insufficiency - may cause fetal anoxia or death

Question 7

Compression of uterine muscles by blood causes…

Answer 7

Tenderness and may prevent good contraction at all stages of labour

Question 8

Posterior abruptions may present with…

Answer 8

Backache

Question 9

Can there be more or less contractions?

Answer 9

More - uterine hypercontractility (>5contractions per 10mins)

Question 10

Why does DIC occur in 10%?

Answer 10

Due to thromboplastin release

Question 11

Is it true that abruption is more likely to be related to conditions occurring during pregnancy and placenta praevia is more likely to be related to conditions existing prior to pregnancy?

Answer 11

Yes

Question 12

When does it typically occur?

Answer 12

After 20 w gestation

Question 13

Describe the placenta

Answer 13

Formed from mother and fetus
Role is to permit gas and nutrient exchange between them 
Has 2 layers:
Decidua basalis - maternal part 
Chorion - fetal part

Question 14

What causes it?

Answer 14

Usually due to degeneration of the uterine arteries that supply blood to the placenta - typically from chronic problems such as smoking or HTN
Diseased vessels rupture causing haemorrhage and separation of placenta

Question 15

What happens if the separation is central or near the margin of the placenta?

Answer 15

Near margin - vaginal bleeding (apparent type)

Central - pocket of blood that stays concealed (concealed type)

Question 16

What complications can occur?

Answer 16

Maternal :
Hypovolaemic shock
Sheehan syndrome 
Renal failure 
DIC - the decidua basalis layer is rich in thromboplastin, an abruption cause large quantities to be released, which causes widespread clotting 
Fetal:
Intrauterine hypoxia and asphyxia 
Premature birth

Question 17

How is it diagnosed?

Answer 17

USS - retroplacental collection of blood, but does not exclude abruption as the sensitivity of detection of a retro-placental clot is poor especially during acute phase

Blood or blood stained amniotic fluid fluid from vagina

Question 18

How is it treated?

Answer 18

Depends on physiological status of mother and fetus and gestational age
IV fluids and blood products - support circulation and prevent coagulation disorder
If mother stable and pregnancy not far enough - monitor closely
If haemorrhage severe or evidence of fetal compromise - emergency C section

Question 19

What investigations should be done?

Answer 19

Diagnosis based on symptoms
Investigations to assess extent and physiological consequences of vaginal bleeding
In cases of severe bleeding: FBC, coagulation screen, 4 units of blood cross-matched
Urea, LFTs, electrolytes

CTG after mother stabilised - fetal hypoxia May show repetitive late or variable decelerations, decreased beat to beat variability or bradycardia
Kleihauer-Betke test: detects fetal blood cells in maternal circulation (and help determine the dose of anti D immunoglobulin to give)

Question 20

What differentials are there?

Answer 20

Abnormal vaginal bleeding during second half of pregnancy usually due to abruption or placenta praevia
Chorioamnionitis
Pre term labour
Uterine fibroid degeneration

Question 21

Is the onset of symptoms acute and sudden or insidious?

Answer 21

Acute and sudden

Placenta praevia more insidious

Question 22

Describe the principles of management

Answer 22

Initial resuscitation
Delivery of baby:
- premature delivery before 37 weeks not recommended if no fetal or maternal compromise
- if >37w and bleeding is present as spotting/mucus active intervention unlikely
- antepartum haemorrhage and maternal and/or fetal compromise = immediate delivery
Post natal: active management of third stage of labour (prevent PPH)
Corticosteroids - risk of pre term birth increased, offer single dose between 24-34 weeks
Anti D - to all the non sensitised rhesus neg cases of antepartum haemorrhage (independent of whether routine antenatal prophylactic anti D given)