Anti-P Allo-Antibodies as a Cause for Recurrent Early Miscarriages & Late Pregnancy Loss

This is a case of a 30 year-old patient, married with no children, after 6 early miscarriages and 2 late abortions, due to anti P allo-antibodies.

The patient has the rare P₁^k phenotype which occurs in less than 0.01% of the population. Cytotoxic IgM and IgG3 antibodies directed against P antigens are associated with a higher than normal rate of spontaneous abortion in women with this rare p₁^k phenotype. Her first pregnancy was at the age of 20, when she presented with a 14/13 weeks of gestation missed hydropic fetus. Upon workup, an A+, DCCcc P₁^k blood type was detected with a titer of 1:256 Anti-P antibodies (IgM and IgG). The products of conception achieved during curettage were frozen for future needs. The patient was urged to cryopreserve her own blood in order to be prepared for a future need of transfusion since only autologous transfusion was recommended.

Upon her second pregnancy, plasmapheresis treatments were given three times weekly since week 5 of gestation. The pregnancy ended at 17 weeks of gestation, again due to missed abortion. Complete recurrent pregnancy loss, thrombophilia workup was negative.

In her third pregnancy, IVIG and plasmapheresis treatments were given alternately three times per week since week 5 of gestation. At 23+5 weeks of gestation the patient presented due to fetal death with disseminated intravascular coagulation, urgent hysterotomy was performed and complete placental abruption was diagnosed. She received 4 units of red packed cells, 20 units of cryoprecipitate and 7 units of fresh frozen plasma.

Her fourth pregnancy was a triplet pregnancy after intrauterine insemination wich ended at 12 weeks of gestation due to missed abortion.

The fifth, sixth, seventh and eigth pregnancies ended at 14-16 weeks of gestation.

In the presented case, after complete workup, anti P antibody was the solitary cause of recurrent pregnancy loss. Early treatments with IVIG and plasmapheresis did not improve the outcome.