title: Part 2: ultrastructural changes of fibrin networks during three phases of pregnancy: a qualitative investigation.
abstract: BACKGROUND
  Normal pregnancy is characterized by significant alterations in the haemostatic system accompanied by an augmented risk of thrombosis.
  
  
  METHODS
  The fibrin network ultrastructure of different phases of pregnancy, namely early pregnancy (week 8-14), late pregnancy (week 36-40) as well as post-partum (week 6-8 after birth) were compared with nonpregnant fibrin networks as well as each other to establish whether differences in fibrin network morphology exist during pregnancy. Scanning electron microscopy was employed to analyse fibrin network morphology.
  
  
  RESULTS
  The fibrin networks from all phases of pregnancy appeared similar to each other, exhibiting prominent coagulant formation, an increase in the formation of minor, thin fibers, and the presence of granular globules. All three phases, however, differ from the typical fibrin network ultrastructure exhibited by the fibrin networks from nonpregnant individuals. The increase in estrogen associated with pregnancy may cause the increase in coagulation factors and ultimately the prothrombotic state characteristic of pregnancy.
  
  
  CONCLUSIONS
  Since no differences were apparent between the different phases of pregnancy it suggests that activation of the coagulation system commences with pregnancy and this pro-thrombotic state continues till at least 8 weeks after birth. These results may shed light on possible pathological mechanisms employed in the development of abnormal or ailing pregnancy.
authors.affiliation: Department of Physiology, School of Medicine, Faculty of Health Sciences, University of Pretoria, Arcadia, 0007, South Africa.
authors.forename: Albe C
authors.initials: AC
authors.lastname: Swanepoel
authors.forename: Barend G
authors.initials: BG
authors.lastname: Lindeque
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Swart
authors.forename: Zeelha
authors.initials: Z
authors.lastname: Abdool
authors.forename: Etheresia
authors.initials: E
authors.lastname: Pretorius
mesh_terms: D000293:Adolescent; D000328:Adult; D004958:Estradiol / Q000097:blood; D005260:Female; D005337:Fibrin / Q000378:metabolism / Q000648:ultrastructure*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D049590:Postpartum Period / Q000097:blood*; D011247:Pregnancy
chemical_list: D004958:Estradiol; D005337:Fibrin
keywords: fibrin network; pregnancy; scanning electron microscopy; thrombosis; ultrastructure