The Correlation Between Inferior Vena Caval Diameter and the Volume of Postpartum Blood Loss

Excessive bleeding after normal birth or cesarean section is defined as blood loss of 1000 mL or more (clinically estimated) within 24 hours after birth. It occurs in about 5% among postpartum women. Postpartum hemorrhage is a leading cause of morbidity and mortality among women giving birth. Postpartum hemorrhage may lead to hemorrhagic shock, renal failure, respiratory failure, need for surgical intervention, blood transfusion and hysterectomy.

The cornerstone of effective treatment is rapid diagnosis and intervention in time. However, in a number of cases there is an underestimation of the volume of blood loss which may lead to delay in diagnosis and treatment. The consequences are even graver in women who delivered by a cesarean section, since unlike a normal birth in which the bleeding is external and visible, the bleeding is usually intra-abdominal, and so the delay in diagnosis may be even longer.

The Inferior Vena Cava (IVC) is a flexible blood vessel sensitive to intravascular blood volume, and its diameter varies accordingly. Its diameter reflects the pressure in the right atrium, which is a measure of the cardiac preload. A number of studies have shown that the IVC diameter changes, before the variations in vital and clinical signs.

Recently, IVC diameter has been assessed as an assessment of intravenous fluid balance in hemodynamically stable patients with a risk of sub-volume shock. The authors concluded that the IVC measurement is a good noninvasive method, compared to catheter insertion into the right atrium, and it is available as a bedside procedure.

In obstetrics the use of IVC to determine blood loos was not widely examined and there is no information regarding the use of IVC diameter as a predictor or as a detection method of postpartum bleeding.

In this study the investigators aim to examine the correlation between IVC diameter and the volume of postpartum blood loss.