Association of the Length of the Third Stage of Labor and Blood Loss Following Vaginal Delivery.

Abstract

The length of the third stage of labor is correlated with blood loss following a vaginal delivery. We aimed to accurately measure blood loss following a vaginal delivery and examine the relation between blood loss and length of the third stage of labor. This was a prospective observational study of singleton pregnancies ≥24 weeks undergoing a vaginal delivery. Blood loss was meticulously measured and the length of the third stage of labor was recorded. The median blood loss of the 600 women was 125 mL (interquartile range 175) and the median length of the third stage of labor was 5 minutes (interquartile range 4). Total blood loss (P = 0.0263) and length of the third stage of labor (P = 0.0120) were greater in pregnancies ≥37 weeks versus <37 weeks. Women with a third stage of labor ≥15 minutes had a significantly greater risk of blood loss >500 mL (relative risk 5.8, 95% confidence interval 8.36-29.88). The median blood loss following a vaginal delivery is 125 mL and the median length of the third stage of labor is 5 minutes. Total blood loss and the length of the third stage of labor are greater in pregnancies >37 weeks. Women with a third stage of labor >15 minutes are 15.8 times more likely to have total blood loss ≥500 mL. As such, it is prudent to consider manual extraction of the placenta at 15 minutes rather than 30 minutes to minimize the risk of excessive blood loss.