• implantation;
  • embryo transfer;
  • chemical pregnancies;
  • IVF immunopotentiation

PROBLEM: It is unclear how paternal leukocyte immunization prevents pregnancy loss. We investigated whether immunization affects early pregnancy, and whether it increases the rate of implantation and early embryonic development at the time of implantation. METHOD: Three groups of women with possible implantation failure were immunized: (1) recurrent biochemical pregnancies (>3), (2) three or more failed in vitro fertilization (IVF) cycles, and (3) IVF after immunization for recurrent abortion (>3). Patients were immunized if antipaternal complement-dependent antibody (APCA) was negative, and mixed lymphocyte culture hyporeactive to husbands lymphocytes. Immunizations were prepared from 100 ml paternal blood separated by Ficoll Hypaque density centrifugation. IVF was attempted after APCA was produced.

RESULTS: In the women with biochemical pregnancies, 10 to 12 subsequent pregnancies developed normally. Seventy-nine subsequent IVF cycles in 33 patients resulted in 20 pregnancies, 16 of which developed normally. Six pregnancies followed 30 cycles in recurrent failed IVF, and 14 pregnancies from 49 cycles in 23 patients with previous habitual abortion.

CONCLUSIONS: This treatment may prevent further biochemical pregnancies if control studies confirm this preliminary observation, but was not shown to affect recurrent failed embryo transfer.