Embryo transfer failure is defined as ≥3 IVF-embryo transfer failures without pregnancy . In
spite of transfer of 3 good quality embryos , just 20-30% of women undergoing IVF will
achieve ongoing pregnancy . There are multiple factors that influence IVF-failure.
Autoantibodies may be one of the possible causes of IVF-failure , especially in unexplained
and mechanical infertility .
In some studies , antiphospholipid antibody is considered as causative factor on implantation
and embryo failure. However some investigators showed that combination therapy with
heparin/aspirin in women with positive antiphospholipid antibody is not effective in
improving of IVF-outcome . In prospective studies were not confirmed association between
antiphospholipid antibody abnormalities and IVF-failure.
Recently has been relationship between thrombophilia and IVF and implantation failure.
The effect of unfractionated heparin in assisted reproductive technology (ART) cycles is
prevention of thrombosis in implantation site . Although its effect is not restricted to
anticoagulation and also can modulate apposition , adhesion , and penetration of embryo .
Other advantages are decreasing thrombophilic risk in COH ( controlled ovarian
hyperstimulation) cycles with administration of gonadotrophins . So heparin make better
pregnancy rate in repeated IVF-ET failures.
There are few studies in regard to heparin effects on IVF cycles outcome . The purpose of
this study is evaluation of unfractionated heparin effects on improvement of ART outcome .
This study was a prospective randomized controlled trial to assess whether administration of
heparin would increased pregnancy rates in women with repeated ET-IVF failures.