Decreased fecundability in Hutterite couples sharing HLA-DR.

Area of Science:

• Immunogenetics
• Reproductive Medicine
• Human Population Genetics

Background:

• Parental human leukocyte antigen (HLA) sharing has been previously associated with extended birth intervals in the Hutterite population.
• Specific HLA loci, such as HLA-DR, were implicated in these prolonged intervals.

Purpose of the Study:

• To prospectively investigate the impact of parental HLA sharing on fecundability and fetal loss rates.
• To elucidate the specific contributions of HLA-DR and HLA-B sharing to reproductive outcomes.

Main Methods:

• A prospective, 5-year study involving 104 Hutterite couples and 154 pregnancies.
• Analysis of time to pregnancy (fecundability) and fetal loss rates in relation to HLA sharing.
• Statistical adjustments for age, gravidity, and kinship.

Main Results:

• Couples sharing HLA-DR exhibited significantly longer median intervals to pregnancy (5.1 months) compared to non-sharing couples (2.0 months) when nursing was stopped prior to the first menses (P = .016).
• Fetal loss rates were significantly higher in couples sharing HLA-B (0.23) versus those not sharing HLA-B (0.12) (P = .041), after adjusting for covariates.

Conclusions:

• Parental HLA sharing, specifically HLA-DR, contributes to longer intervals until clinical pregnancy.
• Increased fetal loss rates associated with HLA-B sharing also play a role in extended birth intervals.
• These findings confirm and specify the influence of HLA compatibility on human reproductive success.