Comparative assessment of changes ADAMTS-13/von Willebrand factor axis in singleton and bichorial biamniotic pregnancy

Aim : to compare changes in the ADAMTS-13 metalloproteinase/von Willebrand factor (vWF) axis in pregnant women with spontaneous or following in vitro fertilization (IVF) singleton and bichorial biamniotic pregnancies. Materials and Methods . A prospective observational randomized controlled trial was conducted. The examination data of pregnant women with singleton (group 1, n = 34) and multiple bichorial biamniotic spontaneous pregnancies (group 2, n = 17), and with singleton (group 3, n = 34) and multiple bichorial biamniotic pregnancies (group 4, n = 34) following reproductive technologies were analyzed. The studied parameters included quantitation of ADAMTS-13 antigen (ADAMTS-13:Ag), ADAMTS-13 activity (ADAMTS-13:Ac) and vWF antigen (vWF: Ag) by chromogenic enzyme immunoassay. Results . A progressive increase in the vWF:Ag level has been revealed that was proportional to escalating gestational age and a decrease in ADAMTS-13:Ag level from the second trimester of physiological non-induced pregnancy, more profound during twin pregnancy (p < 0.001). In induced pregnancy, vWF:Ag level increased, ADAMTS-13:Ag - decreased starting from 6-7 weeks of gestation (p < 0.001), more prominent in twin pregnancy (p < 0.001). The ADAMTS-13 activity in induced single and multiple pregnancies did not differ significantly by trimester but was lower compared with non-induced pregnancies of matched timeframe. The most pronounced decrease in the ADAMTS-13:Ag/vWF:Ag ratio was observed in multiple induced pregnancies. Conclusion . Stimulation of superovulation and subsequent embryo transfer into the uterine cavity is accompanied by higher procoagulant vascular endothelium properties, vWF release, which activates platelets and the coagulation cascade from the early stages of induced pregnancy. vWF hyperreactivity is compensated by the expenditure of ADAMTS-13, which level declines dramatically during twin pregnancy creating conditions for disruption of hemostasis gestational adaptation and increases a risk of thrombotic complications and obstetric pathology.