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

To evaluate the distribution of Lewis blood group phenotype and secretor status among women treated for infertility.

In vitro fertilization unit of a university hospital.

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.

Determination of ABO and Lewis blood group phenotypes.

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.

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.