Читать книгу Managing Medical and Obstetric Emergencies and Trauma - Группа авторов - Страница 103

During pregnancy there is an increase in circulating blood volume of approximately 40% due to increases in both plasma and red cell volume. In a 70 kg woman, blood volume in pregnancy increases from 70 to 100 ml/kg (from 4900 to 7000 ml). This circulating volume enables the pregnant woman to lose 1200–1500 ml of blood before demonstrating any signs of hypovolaemia (35% of her circulating blood volume). This enhanced ability to compensate for blood loss increases our risk of underestimating the severity of blood loss, occasionally even until the point of maternal collapse.