Comparison of Hemostasis Parameters in Vaginal versus Cesarean Deliveries

Abstract

Several studies have documented coagulation changes that occur with normal vaginal deliveries, while several others have shown the beneficial effects of epidural analgesia in vascular and orthopedic procedures. One study has documented the beneficial effects of epidural analgesia in normal vaginal deliveries. To date, no studies have been conducted examining in vivo hemostasis activity during cesarean delivery with spinal anesthesia in normal pregnancies. <p>This is a prospective longitudinal study measuring hemostasis markers in healthy parturients having a cesarean section with spinal anesthesia. The sample population consists of 15 patients, aged 18-45, ASA classification of II, and greater than or equal to 34 weeks gestation scheduled for cesarean delivery. Four blood samples were drawn at the following times: prior to cesarean section, immediately following cesarean section, 3 hours and 24 hours postpartum. The hemostasis tests included: D-dimer, fiber-fibrogen degradation products (FDP), beta-thromboglobulin (BTG), platelet factor 4 (PF 4), platelet count, hemoglobin, hematocrit, prothrombin fragments 1+ 2 (PF 1+ 2), antithrombin III (AT III), alpha-2-antiplasmin (A2A), fibrinogen, and thrombin-antithrombin III (TAT) complexes. These results were compared to a previous study which examined healthy parturients who received epidural anesthesia and healthy parturients without epidurals having a vaginal delivery. <p>The sample consisted of a total of 75 patients to detect a 1 standard deviation difference between the three groups. Analysis of Variance for Repeated Measures with Post Hoc T-tests was used to detect differences in descriptive variables and hemostasis markers. A p value < 0.05 was accepted as significant. The power for this study with an effect size of .60 is .59. <p>In the cesarean group, PF 4 and BTG levels showed the greatest increase 3 hours postpartum. Antithrombin III was decreased at delivery and 3 hours postpartum, while PF 1+2 and TAT complex increased at delivery and 3 hours postpartum. Alpha-2-antiplasmin decreased at delivery and 3 hours postpartum. An increased frequency of a positive D-dimer was found with each blood draw, and the percent of FDP in the 10-40 ug/mL range increased successively in the first three draws. These findings suggest an increase in platelet, coagulation, and fibrinolytic activity at delivery and in the immediate postpartum period in the cesarean section group. <p>There was no significant difference in platelet activation among the groups. Platelet factor 4 levels were significantly greater in the non-epidural group at delivery. The cesarean group did show significantly lower AT III levels at delivery, 3 hours and 24 hours postpartum (p < 0.005) when compared to both vaginal groups. While not statistically significant, the cesarean group demonstrated lower levels of fibrinogen, A2A, and platelets at delivery and 3 hours postpartum compared to the vaginal groups. Overall, similar changes in hemostasis occurred among the three groups. However, the greater decrease in AT III, fibrinogen, A2A and platelets in the cesarean group may reflect an increase in platelet, coagulation, and fibrinolytic activity with cesarean section as compared to vaginal delivery.