This chapter covers a wide spectrum of causes for collapse on the labour ward or in the emergency department, for the first steps in management. The latest guidance on the management of cardiac arrest which the obstetric anaesthetist will be required to immediately attend and initiate in a pregnant woman is described in detail, with the steps needed to progress to perimortem caesarean delivery if resuscitation is not immediately effective. The serious complications of regional anaesthesia; high blocks, total spinals, and local anaesthesia toxicity are emphasized. Anaphylaxis, magnesium toxicity, and management of trauma in the obstetric patient are also outlined.