Association of the Lewis blood-group phenotype with infertility in women

Objective - To evaluate the distribution of Lewis blood group phenotype and secretor status among women treated for infertility. Setting - In vitro fertilization unit of a university hospital. Patients - Forty-seven consecutive infertile women with mechanical (n = 31) or unexplained (n = 16) infertility scheduled for IVF-ET. The control group was formed of 47 fertile women from our database and additional new women matched for age. Main Outcome Measures - Determination of ABO and Lewis blood group phenotypes. Results - Of the 47 subfertile women, 12 had blood type A (25.5%), 10 type B (21.3%), 4 type AB (8.5%), and 21 type O (44.7%); 38 had Le (a^-b⁺) (80.9%), 4 had Le (a⁺b^-) (8.5%), and 5 had Le [a^-b^-) (10.6%). Of the 47 controls, 17 had type A (36.2%), 12 type B (25.5%), 4 type AB (8.5%), 14 type O (29.8%); 26 had Le (a^-b⁺) (55.3%), 11 had Le (a⁺b^-) (23.4%), and 10 had Le (a^-b^-) (21.3%). The difference in the proportions of the A, B, AB, and O phenotypes was not statistically significant. The proportion of combined recessive and nonsecretor phenotypes Le (a⁺/^-b^-) was significantly lower in subfertile women (9/47) as compared with fertile controls (21/47) (P = 0.014). The difference in the proportions of the Lewis blood group phenotypes between the unexplained and the mechanical infertility groups was not statistically significant. Conclusions - Subfertile women have an increased frequency of the Le (a^-b⁺) blood group phenotype. Our hypothesis is that the presence of exposed fucosylated determinants such as Le(b) on the surface of endometrial cells may interfere with implantation.