Expression of an Immunomodulatory Protein Known as Progesterone Induced Blocking Factor (PIBF) Does Not Correlate With First Trimester Spontaneous Abortions in Progesterone Supplemented Women


  • Dr. Jerome H. Check,

    Corresponding author
    1. The University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School at Camden, Cooper Hospital/University Medical Center, Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Camden, New Jersey
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  • Adam Ostrzenski,

    1. Department of Obstetrics and Gynecology, Howard University College of Medicine, Washington, D.C.
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  • Rudolf Klimek

    1. Department of Obstetrics and Gynecology, Jagiellonian University College of Medicine, Krakow, Poland
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PROBLEM: An immunomodulatory protein known as the progesterone induced blocking factor (PIBF) has been found to positively correlate with early pregnancy beta human chorionic gonadotropin (B-hCG) levels. The study presented herein evaluated PIBF levels from conception to the end of the first trimester to determine if lower levels will correlate with first trimester spontaneous abortions (SAB).

METHOD: Progesterone induced blocking factor expression by lymphocytes measured using an immunocytochemistry method was compared in pregnant women with ongoing vs. failed pregnancies.

RESULTS: There were no differences in the proportion of women having lymphocytes expressing PIBF or in the median numbers when comparing ongoing vs. failed pregnancies. There was no B-hCG interval where failed pregnancies were found to have lower frequency of PIBF expressing lymphocytes.

CONCLUSION: Inadequate PIBF expression independent of low P levels does not appear to be an etiologic factor for first trimester SABs; thus measuring this protein in pregnant women lacks practical usefulness.