Part 2: ultrastructural changes of fibrin networks during three phases of pregnancy: a qualitative investigation

Normal pregnancy is characterized by significant alterations in the haemostatic system accompanied by an augmented risk of thrombosis.

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.

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.

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.