Maternal critical care can be defined as the specialised care of pregnant and postpartum women whose conditions are life-threatening. This chapter explores the consideration for both the location and care that might be required in the unwell pregnant or postpartum woman. Key learning points: Maternal critical care is required for pregnant and postnatal women with complex medical, surgical and obstetric problems. Maternal critical care requires the collaborative involvement of a multi-professional team of midwives, obstetricians, anaesthetists, intensive care specialists, obstetric physicians, and neonatologists (if the woman is still pregnant). Maternal critical care charts should be used for documenting observations, fluid balance, ongoing clinical investigations, results and medical reviews. Structured review sheets provide a useful framework for multi-professional reviews. Critical care might be provided on the labour ward, an enhanced maternal care unit, or a critical care unit; depending on the woman’s condition, and the capabilities of the units. Women requiring critical care outside of the maternity unit should receive frequent obstetric and midwifery reviews to ensure the maintenance of their routine antenatal, intrapartum and postpartum care. Women with life-threatening conditions should not be denied investigations or treatments simply because they are pregnant or breastfeeding. All healthcare professionals should be aware of the potential long-term effects of critical illness on a woman’s health, in particular her mental health.