Rh isoimmunization during pregnancy: antenatal prophylaxis.

Of 3533 Rh-negative women who began a pregnancy without detectable Rh antibodies, 62 (1.8%) demonstrated evidence of Rh isoimmunization during pregnancy or within 3 days after delivery. All denied transfusions as well as abortions or previous pregnancies not followed by the administration of Rh immune globulin. Rh isoimmunization during pregnancy or within 3 days after delivery, which will not be prevented by the administration of Rh immune globulin after delivery, is the most important cause of residual Rh isoimmunization. A clinical trial of antenatal administration of Rh immune globulin, initially at 34 weeks's and subsequently at 28 and 34 weeks' gestation, in 1357 Rh-negative pregnant women who were delivered of Rh-positive babies, was effective in preventing the development of Rh isoimmunization during pregnancy or within 3 days after delivery. Antenatal prophylaxis with Rh immune globulin will be necessary if the incidence of Rh isoimmunization is to be reduced to its lowest possible level. Antenatal prophylaxis at 28 weeks' gestation is now an insured service in Manitoba.

Relative positions of chromosome 1 loci Fy, PGM1, Sc, UMPK, Rh, PGD and ENO1 in man.

Ongoing linkage studies of red cell antigens and enzymes in many families along with concentration on a large Mennonite kindred segregating for Sc have resulted in lods, recombinant: nonrecombinant counts and multi-point information which support an order with approximate recombination fractions as measured in the male as follows: Fy--.25--PGM1--.20--Sc--less than .05--UMPK--.15--Rh--.20--PGD, with ENO1 close to PGD. The insertion of Sc and UMPK between PGM1 and Rh allows the recognition of double crossing-over between the latter pair; indications are that this is not a rare event in the female. In the male no evidence of double crossing-over was found in the similar distances PGM1--Rh and Sc--PGD in 13 and 19 opportunities respectively.

Rh isoimmunization, Manitoba, 1963-75.

The number of Rh-isoimmunized pregnancies in Manitoba has been reduced from 223 and 228 in the years ending Oct. 31, 1963 and 1964 to 60 and 62 in the years ending Oct. 31, 1974 and 1975. The number per 1000 total births in the same years has decreased from 10.0 and 10.6 to 3.4 and 3.5 Perinatal mortality rates in those years decreased from 13.8 amd 15.7% to 0 and 2.2%, respectively. The number of perinatal deaths has been reduced from 55 in the first 2 years reported to 1 in the last 2 years. Among the 121 isoimmunized women pregnant in the 2-year period ending Oct. 31, 1975, isoimmunization was due to failure to give Rh immune globulin after delivery in 33 and failure to give it during pregnancy in 48. Of the remaining 40, 37 were immunized before Rh immune globulin became available. Complete prevention of Rh isoimmunization and therefore of all perinatal deaths from Rh erythroblastosis can only be achieved through universal Rh testing prenatally and immediately after delivery, and institution of an antenatal Rh prophylaxis program.

Colton blood groups in Canadian Caucasians: frequencies, inheritance and linkage analysis.

In a series of 726 random Caucasian adults tested with anti-Coa and anti-Cob allele frequencies were Coa 0.9470, Cob 0.0530. The distribution of Colton phenotypes in 205 children of 57 selected families was in accordance with expectation. A linkage analysis of Co and 26 other loci indicates that Co is not closely linked to AcP1, ABO, AK1, Ch, Do, GLO, Gm, GPT, HLA, Hp, K, Lu, MN, PGM1 or Rh and does not lie between PGD and PGM1 on chromosome 1.

The Lutheran and secretor loci: genetic linkage analysis.

Linkage analysis of Lu and Se and 31 other loci indicate that Lu:Se are not closely linked to ABO, ACP1, Co, Do, Est.D,Fy, GC, Gm, GLO:HLA, GPT, Inv, Jk,K,MN,P,PGD,PGM1, Rh,Sc, UMPK OR Yt. Lod scores for 18 families informative for Lu:Se gave no evidence for sex differentiation in recombination fraction: theta for males was 0.07, and for females, .08.

The Diego blood groups: a genetic linkage analysis.

Data are presented which show that the Diego blood groups are not part of the Dombrock or Yt blood group systems and that the locus controlling Di is not closely linked to the loci controlling ABO, Fy, Jk, Kell, MNSs, Rh, Gm, Inv, AcP,ADA, PGD, and UMPK.

An error in Rh testing in pregnancy.

Anti-D (anti-Rho) in the blood of two Rh-negative pregnant women was believed to be due to active immunization. In the first case, however, antibodies were no longer detectable 2 weeks later. In the second case they disappeared by the end of 31 weeks. It was discovered that both women had been given immune globulin (human) because of exposure to rubella. The globulin given to the first woman probably contained about 0.1 mug of anti-D per ml; that given to the second probably contained about 0.6 mug of anti-D per ml. Both babies were O Rh-positive. Both women were given Rh immune globulin after delivery. Both have completed a further pregnancy and no anti-D has been found on many tests. In tests carried out in 1971 all samples of immune globulin (human) examined contained anti-D, but usually in inconsequential trace amounts.