A woman aged 28 years is in labour when she suddenly collapses. This is her fourth preg- nancy and she has had three previous spontaneous vaginal deliveries at term. This preg- nancy has been uncomplicated and she has been admitted with contractions at 37 weeks and 6 days.
On arrival on the labour ward the fetus was palpated to be normal size, cephalic and 3/5 palpable abdominally. The cervix was 3 cm dilated and the membranes were intact. Blood pressure and urinalysis were normal. Initial auscultation of the fetus was reassuring and the heart rate has continued to be normal (around 140/min) on intermittent auscultation.
Five minutes ago spontaneous rupture of membranes occurred during a contraction, with a large gush of clear fluid from the vagina. The woman reported an urge to push at that stage and then became confused and disorientated saying that she could not breathe and was going to die. Immediately following this she collapsed.
The woman is unconscious and unrouseable to painful stimuli. The blood pressure is 98/40 mmHg and heart rate 120/min. The oxygen saturation is 86 per cent on air and respiratory rate 20/min. The heart sounds are normal but on chest examination there are inspiratory crackles throughout the chest.
The abdomen is soft with intermittent contractions continuing, and in fact the fetal head is now visible at the perineum. There is no vaginal bleeding.
· What is the likely diagnosis and differential diagnosis?
· How would you manage this woman?
The diagnosis is likely to be an amniotic fluid embolism. Differential diagnoses include:
· pulmonary embolism
· myocardial infarction
· vasovagal attack.
The factors leading to the diagnosis of amniotic fluid embolism rather than one of the dif- ferentials are the history of sudden collapse without preceding chest pain, and the fact that this occurred around the time of rupture of membranes. Amniotic fluid embolism is also often preceded by premonitory symptoms, restlessness, confusion or cyanosis. A vasovagal attack is very unlikely as this is usually associated with bradycardia and would not account for the chest signs or decreased oxygen saturation.
Amniotic fluid embolism occurs when amniotic fluid enters the maternal circulation. This is usually during labour but can occur with maternal trauma or very occasionally after delivery. It is rare (five cases in the last Confidential Enquiry into Maternal and Child Health 2000–2002), unpredictable, sudden and commonly fatal. Women who die tend to do so within an hour or so of becoming unwell, having developed acute hypoxia, coagu- lopathy and cardiac arrest.
The baby should be delivered immediately as this will facilitate more effective resuscita- tion of the mother. In this case a simple forceps delivery should be performed. If the baby was not deliverable vaginally then immediate Caesarean section should be performed. Massive postpartum haemorrhage is very likely and syntocinon infusion should be com- menced with further postpartum haemorrhage strategies such as ergometrine, carboprost, embolization or hysterectomy anticipated.