Obs Emergencies - Amniotic Fluid Embolism

Question 1

What is amniotic fluid embolism?

Answer 1

Bolus of amniotic fluid enters maternal pulmonary circulation and produces massive perfusion failure, bronchospasm, and shock

Amniotic fluid embolism (AFE) is a recognised, yet rare cause of maternal collapse. It is often a fatal complication of pregnancy and the puerperium, and is a direct cause of maternal death.

The most up to date UK data states that there is an incidence of 2/100,000 pregnancies.

The cause of this phenomenon is still under debate however possible roles have been attributed to strong uterine contractions, excessive amniotic fluid and disruption of vessels supplying the uterus.

It therefore remains a condition that is neither predictable nor preventable, with no established accurate premortem diagnostic test or investigation.

Question 2

What are the risk factors for amniotic fluid embolism?

Answer 2

multiparity, placental abruption, IUFD, precipitate labor, surgical/medical TOP, abdominal trauma, ECV, amniocentesis

Question 3

What are the clinical symptoms of amniotic fluid embolism?

Answer 3

The physiology related to amniotic fluid embolism has been described as similar to anaphylaxis or severe sepsis. As such, the manifestations of this complication of pregnancy resemble these disease processes.

It is characterised as an acute condition with the sudden onset of:

Hypoxia/respiratory arrest
Hypotension
Fetal distress
Seizures
Shock
Confusion
Cardiac arrest
Disseminated intravascular coagulation (this may be the first sign in some cases however nearly all patients will go on to develop this within 4 hours)
The differential diagnosis will include other conditions that present in this way – such as pulmonary embolism, anaphylaxis, sepsis, eclampsia and myocardial infarction. It is therefore difficult to confirm the diagnosis and the focus should therefore revolve around resuscitation and stabilisation of the patient.

Question 4

Definitive diagnosis of amniotic fluid embolism is only definitively confirmed on

Answer 4

post mortem and demonstrates fetal squamous cells along with debris in the pulmonary vasculature