Interaction between oral estrogen plus progestogen therapy and ABO blood groups on coagulation activation in postmenopausal women.

OBJECTIVE

The aim of this study was to investigate the effect of postmenopausal hormone therapy on coagulation and whether this effect differs according to ABO blood groups.

METHODS

This was a prospective observational study to evaluate factor VIII (FVIII) activity, factor von Willebrand (vWF), and D-dimer (D-Di) levels and ABO blood groups in 61 postmenopausal women using oral estrogen plus progestogen therapy (EPT; 2 mg estradiol + 1 mg norethisterone acetate) for 3 months and in 101 women not using EPT. After 3 months, all eligible women who had completed the treatment scheme proposed for the EPT group or those who opted to participate but had not undergone EPT had a blood sample collected for analysis.

RESULTS

Significant differences were observed in FVIII activity and vWF levels in the control group between those carrying group O and non-group O blood. For EPT users, significant differences were observed for FVIII activity, vWF, and D-Di levels. After a multivariate regression analysis, FVIII activity and ABO blood groups were independently associated with vWF levels, whereas interaction between ABO blood groups and EPT were independently associated with FVIII activity. Besides diabetes, the ABO × EPT interaction was also noted to be independently associated with D-Di levels.

CONCLUSIONS

These findings suggest an interactive effect between oral EPT and non-O blood groups, contributing to the mechanism by which estrogen triggers the hypercoagulability state and increased risk for venous thrombosis in women undergoing oral EPT.