Miscarriage in the first trimester according to the presence or absence of the progesterone-induced blocking factor at three to five weeks from conception in progesterone supplemented women

PURPOSE: To determine if the failure to detect the immonomodulatory protein progesterone induced blocking factor (PIBF) at three to five weeks of seemingly normal pregnancies in women supplemented by extra progesterone is associated with a higher miscarriage rate. METHODS: Progesterone-induced blocking factor expression by lymphocytes was measured by an immunocytochemistry technique. The serum beta human chorionic gonadotropin (hCG) and/or ultrasound were also deemed appropriate so that by these criteria there was no evidence of a poor pregnancy. The minimum progesterone dosage was 200 mg twice daily vaginal suppositories. RESULTS: Progesterone-induced blocking factor was detected in 17/39 (43.5%) of pregnant patients at this early time. There were three miscarriages by 12 weeks in this group (17.6%). The miscarriage rate was 6/21 (28.5%) in those where it was not detected. CONCLUSIONS: There was insufficient power to show significance. However there seems to be a trend for higher rates of miscarriage when PIBF is absent so these preliminary data encourage continuation of the study.