This review briefly updates issues related to physiology of pregnancy and peripartum period, maternal mortality and obstetric ICU admissions. Maternal mortality (MM) is still a frequent event, occurring mainly in developing countries. Causes of MM vary: in developed countries, complications of anaesthesia/caesarean section (20%), hypertensive disorders (16%), embolism (15%) and hemorrhage (13%) prevail. In developing countries, obstetric hemorrhage, hypertensive disorders and sepsis are the commonest. Other causes are region-specific, as HIV-AIDS in Africa, anemia and obstructed labor in Asia, and unsafe abortion in Latin America and the Caribbean.
Obstetric intensive care unit (ICU) requirement can be considered an indicator of severe maternal morbidity in itself. In high and low-income countries, obstetric patients represent < 5% and 10-15% of ICU admissions, respectively; usually occur in the post-partum period, and reasons are obstetric over medical. The most common obstetric causes are: hypertensive disorders, hemorrhage, and sepsis of pelvic origin, with regional variations in incidences. Medical causes of admission, however, show great disparity. Mechanical ventilation is required in 20-65% of patients, and pulmonary artery catheter is seldom used. ICU maternal mortality is < 5% in high-income countries, but might reach between 10-60% in low-income countries. APACHE II score usually overpredicts ICU mortality.