Coagulation Profile Surrounding Normal Cesarean Delivery
Abstract Number: T-33
Abstract Type: Original Research
Introduction: Hypercoagulability of normal pregnancy peaks at the time of delivery.1 The source of the procoagulants may be in the form of microparticles (MPs).2 Tissue-factor containing MPs are known to stimulate coagulation although sometimes pathologically. It has been proposed that TF-containing MPs may be released from the placental bed during normal delivery, and that release may be exaggerated in the setting of post-partum hemorrhage (PPH).3 We hypothesized that an increase in TF-bearing MPs would occur around the time of normal cesarean delivery (CD) and subside over several hours.
Methods: In this IRB-approved study we consented from 9 healthy parturients with a singleton pregnancy, gestational age >/= 36 weeks, who presented for scheduled CD. Exclusion criteria were hypertensive diseases of pregnancy, diabetes, known placental abnormalities, and coagulation disorders. Demographic data were collected. A 16g IV was placed for 5 blood draws: baseline antepartum, immediately after delivery of the placenta, then 1, 4, and 24-36 hours postpartum. Blood was collected in an ACD “yellow top” tube and centrifuged at 2000g for 20 min to separate plasma, which was aliquoted and stored at -800C. Samples underwent flow cytometry, confirmatory image stream microscopy, and staining to determine if MPs were endothelial, placental or leukocyte derived. TF levels were measured using ELISA. Comparisons were made for each assay result using ANOVA for repeated measures.
Results: Median (range) age of the parturient was 32 (24-39) years, BMI was 32 (26-41) kg/m2 and all patients had a gestational age between 39 0/7 to 39 6/7 weeks. There was a significant peak in TF-negative placental-derived microparticles immediately after delivery of the placenta (P = 0.001) (Figure). The other MPs were not different across time points.
Discussion: A peak in TF-negative placental-derived MPs occurs immediately after delivery of the placenta. Further investigation is needed to identify if procoagulant substances other than TF are represented on these placental-derived MPs, if our results can be replicated in laboring patients, how co-morbidities and PPH affect these results, and if presence of certain placental-derived MPs may identify patients at risk for PPH.
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2. Boer K. J of Thrombosis and Haemostasis 2007;5:2415-20
3. Morel O. Arterioscler Thromb Vasc Biol 2006;26:2594-2604