Maternal collapse is an acute life-threatening event where the mother becomes unconscious due to cardiorespiratory or neurological compromise at any stage in pregnancy or up to 6 weeks postpartum. During resuscitation, aortocaval compression reduces cardiac output during chest compression. The risk of aspiration during resuscitation is increased due to a more relaxed lower oesophageal sphincter muscle and elevated gastric acid volume production. Amniotic fluid embolism (AFE) can also lead to fetal collapse of unknown origin that precedes maternal collapse. Uncontrolled hypertension can lead to intracranial haemorrhage. Typical clinical signs are severe, never-experienced headache preceding maternal collapse. Hypervolaemia, hypoxia, hyperkalaemia/metabolic disorders, hypothermia, thromboembolism, toxicity, cardiac tamponade, tension pneumothorax are some of reversible causes for maternal cardiac arrest. A cardiac arrest trolley and defibrillator, including wedge for left lateral tilt should be available on all maternity units and checked daily.