Gestational progesterone suppresses embryotoxic action of the complement system to chick embryo.

OBJECTIVE: In this paper the relation between progesterone levels and embryotoxic effect of serum complement was studied.

DESIGN: The aim of this study was to validate hypothesis that progesterone is strong inhibitor of complement embryotoxic action.

SETTING: We used chick embryo like an experimental model for evidence of our hypothesis. We treated chick embryos by sera acquired from healthy pregnant woman with physiologically elevated levels of progesterone and normal complement activity. We investigated embryotoxicity of these sera.

RESULT: We noticed a significant decrease of sera embryotoxicity inversely related to serum levels of progesterone. The main finding: The embryotoxicity of sera is reversally dependent on progesterone level.

CONCLUSIONS: These findings bring a new knowledge to the role of progesterone and complement system mainly in initial stages of pregnancy and in some cases of spontaneous abortions.