Blood groups are considered concordant among all those groups that may be possible from a biological point of view after the combination of two different blood groups. So, two parents who have, for example, blood group A + and B + respectively, could conceive a child naturally with a group 0 -. That is to say, the “concordance of blood group” does not mean “equality of blood type.” The primary objective when selecting the egg donor is to have phenotypic similarity, which is, physical resemblance to the receptor in order to facilitate the integration of the newborn in the family and social environment, which is consistent with the assisted reproduction law currently in force in Spain.
EUGIN Clinic follows this policy, and in so far as possible, will also try allocating donors of concordant RH factor and blood group. However, this will only be mandatory from a medical point of view in certain cases. One such situation could be when the woman is Rh negative and is isoimmunized (has antibodies against Rh) by a previous pregnancy. In these cases, the allocation of Rh-negative donors would be necessary. In conditions where, for example, the woman is Rh negative and she does not have Rh isoimmunization, or even where her male partner may be Rh positive, the allocation of Rh negative donors would not be necessary. In the remaining cases, there is no medical indication to indicate on a mandatory basis the concordance with the group and Rh, since we must take into account the following considerations:
- The risk to the resulting newborn in the case of non-concordant group or Rh factor is almost nil except in those of isoimmunization as already stated.
- The group and Rh factor is not currently listed on any official document (national ID, passport etc.) because it used to lead to many errors in the transfusion policy. If blood is required, determining the blood group is always done at the same time. So, today this data is only known if the patient communicates it to others as part of the confidential information.
- When there were no reliable paternity tests, the group and Rh factor was a rather imprecise way o being able to suspect that a child was not the biological child of both parents. However, today, paternity tests analyze DNA fragments and are almost totally reliable. These tests cannot be done without the consent of the person involved, except by court order.
For all these reasons, the oocyte donation programme at EUGIN gives priority to the physical resemblance of the donor-recipient over the group and Rh factor when selecting the egg donor or sperm donor.