LAUSR

Introduction Oocyte donation pregnancies are associated with a higher incidence of pregnancy complications, such as pre-eclampsia. In OD pregnancies the fetus may be completely allogeneic to the mother, since the fetus carries paternal and donor derived Human Leukocyte Antigen (HLA) genes. The higher incidence of pregnancy complications might be related to the high level of immunogenetic dissimilarity, reflected by the number of HLA mismatches. Objective/hypothesis We studied the number of HLA mismatches in OD pregnancies in relation to pre-eclampsia. Methods In this retrospective study, HLA typing was performed in 99 women pregnant after OD and 118 children between 2004 and 2017. The HLA-genotype was determined for HLA-A, HLA-B, HLA-C (HLA class I), HLA-DR and HLA-DQ (HLA class II). The number of HLA mismatches of the child was calculated at the national reference laboratory for histocompatibility testing (LUMC). Results Twenty-two women developed preeclampsia in our group of 99 oocyte donation pregnancies. Maternal age and the frequency of twin pregnancies was significantly higher in the pre-eclampsia group, whereas gestational age was significantly lower in OD pregnancies complicated by pre-eclampsia. The number of HLA class II mismatches of the child was significantly higher in the cases with pre-eclampsia (n = 2.35 vs 3.15; p = 0.014; OR = 1.964 (95% CI = 1.149–3.355)), even after correction by logistic regression for maternal age and twin pregnancies. No significant effect of HLA class I mismatches was observed. Discussion This study showed that OD pregnancies with a higher level of HLA class II mismatches have a significantly higher chance to develop pre-eclampsia. Hence, HLA class II matching could be considered in OD pregnancies to decrease the risk of developing pre-eclampsia, and preventive pre-eclampsia treatment (aspirin) could be considered in OD pregnancies with a higher level of HLA class II mismatches.