[Immunological aspect of spontaneous and habitual abortion]

Spontaneous and habitual abortions are one of most painful experiences for couples expecting a child. It is an extraction or expulsion from its mother of a fetus weighing 500 g or less or pregnancy termination before 24 completed weeks of gestation. The incidence of spontaneous abortion is 15%-25% of all recognized pregnancies. 1%-2% of all women abort habitually. Beside many recognized causes of spontaneous and habitual abortion, 10%-50% are still unknown etiology. The larger numbers of unexplained abortions have immunological reason. By pre-embryonic reorganization of maternal immune system starts subsequent immunoprotective mechanism. There the key role has PIBF (Progesterone induced blocking factor) whose production depends of sufficient circulating progesterone concentration. PIBF supports Th-2 cytokines, inhibits nuclear killer cells (NK cells), induces an increased production of asymmetric, non-cytotoxic blocking antibodies. The production of pro-inflammatory, cytotoxic cytokines interferon-y (IFN-y), tumor necrosis factor-alpha, (TNF-alpha), interleukin-2 (IL-2) is reduced. There is the controversy about treatment of spontaneous and habitual abortion: from "do nothing" to routine pharmacological "support of every the pregnancy".