The angiogenesis inhibitor histidine-rich glycoprotein (HRG) constitutes one of several examples of molecules regulating both angiogenesis and hemostasis. The antiangiogenic properties of HRG are mediated via its proteolytically released histidine-and proline-rich (His/Pro-rich) domain.

HRG and fibrinogen might be involved in the hypercoagulability and the angiogenic imbalance seen in early-onset preeclampsia.

Histidine-rich glycoprotein (HRG) is involved in fibrinolysis and coagulation, the immune system and angiogenesis. These processes are all crucial in establishing and maintaining pregnancy. The primary aim of this pilot study was to determine if HRG affects pregnancy outcome. The secondary aim was to investigate if a specific genetic polymorphism (rs9898 C/T) in the HRG gene is associated with pregnancy results. The polymorphism leads to expression of either a serine or proline residue at position 186 in the protein sequence. In this study, women undergoing IVF were included. The genetic polymorphism in the HRG gene was analysed by Western blot and single nucleotide polymorphism analysis. None of the women homozygous for the serine at residue 186 became pregnant whereas the women homozygous for proline at residue 186 had higher than expected pregnancy rates. As far as is known,this is the first study to show that a specific genetic polymorphism in the HRG gene of a woman affects her chances of becoming pregnant after IVF. The results may be essential in improving advice and IVF treatment for couples with unexplained infertility.